(2023), pneumonia incidence has reemerged in more unpredictable and unusual patterns. Further, there is a striking rise in childhood pneumonia in China, although no novel pathogens have been identified thus far.

 

To learn more about COVID-19, refer to the COVID-19 NursingCE course.

Pathophysiology and Etiology

Pneumonia is an infection of one or both lungs that causes fluid or pus buildup in the alveoli. It results from an inflammatory process and most commonly affects the alveoli, interstitial spaces, and bronchioles (Ignatavicius & Workman, 2018; NCI, n.d.d). Pneumonia may be noninfectious or infectious. Noninfectious pneumonia can result from the inspiration of irritants (toxic gases, chemicals, smoke) or the aspiration of water, food, or fluid, including saliva and vomit. Infectious pneumonia can be caused by fungi, bacteria, viruses, and parasites, whereby the organism enters the airway mucosa and multiplies within the alveolar spaces. Transmission can occur through one's environment, direct contact with others, invasive devices, and contaminated medical equipment or supplies (Ignatavicius & Workman, 2018).

The most common causes of pneumonia can be grouped into three categories: typical bacteria, atypical bacteria, and respiratory viruses. Typical and atypical pneumonia organisms are classified in terms of ease of culture positivity. Typical bacteria can be cultured on standard media or seen on a traditional Gram's stain and include Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus pyogenes (group A strep or GAS), Haemophilus influenzae, Moraxella catarrhalis, anaerobes, and aerobic gram-negative bacteria. Atypical pneumonia cannot be cultured on standard media or viewed consistently on a Gram stain. These include Legionella pneumophila, Mycoplasma pneumoniae, Chlamydia pneumoniae, and Chlamydia psittaci. Respiratory viruses responsible for pneumonia may include influenza A and B, coronaviruses, rhinoviruses, parainfluenza viruses, respiratory syncytial virus (RSV), and adenoviruses (Ramirez, 2024; Sattar & Sharma, 2023).

The severity of pneumonia and the extent of lung involvement depends on the patient's immune response. Primary host mechanisms, such as hair in the nasal passages and mucus in the nasopharynx and oropharynx, are in place to prevent infection. Alveolar epithelial cells produce surfactants A and D, proteins that opsonize bacteria that make it past these initial defenses. Alveolar macrophages are then able to engulf and eliminate the bacteria by phagocytosis. Alveolar macrophages initiate the inflammatory cascade, which leads to the release of cytokines such as interleukin-1, tumor necrosis factor, and granulocyte colony-stimulating factor. Fluid collects in and around the alveoli, with few neutrophils and macrophages (white blood cells [WBCs]) initially. The inflammatory cytokine interleukin-8 drives chemotaxis (movement of motile WBCs), while granulocyte colony-stimulating factor accelerates neutrophil maturation. Bacteria can multiply quickly in immunocompromised patients, such as those with cancer or HIV (Sattar & Sharma, 2023).

Additional WBCs migrate to the infected area, which causes capillary leakage, edema, and exudate. As the lobe becomes consolidated with serous exudate and fibrin, the alveolar walls thicken. This consolidation and thickening reduce gas exchange and interfere with oxygenation. Red blood cells migrate into the alveoli as capillary leakage facilitates the spread of infection to other lung regions and, in some cases, leads to hemoptysis (bloody sputum). Fibrin and tissue edema cause the lungs to stiffen, leading to reduced compliance and decreased vital capacity. Atelectasis further reduces the ability of the lungs to oxygenate the circulating blood, worsening hypoxemia (decreased arterial oxygen levels). The constitutional symptoms of pneumonia are primarily related to cytokine release, such as fever caused by the release of interleukin-1 and tumor necrosis factor. In lobar pneumonia, consolidation occurs in a segment or lobe of the lung. Bronchopneumonia consists of diffuse patches of consolidation around the bronchi. If the infection spreads into the pleural cavity, empyema results. Septicemia results if the organism moves into the bloodstream (Ignatavicius & Workman, 2018; Sattar & Sharma, 2023).

Types of Pneumonia

There are dozens of causes of pneumonia, which may be grouped by causative agent (antigen) or by acquisition site. Pneumonia types acknowledged by the American Thoracic Society and Infectious Diseases Society of America (ATS/IDSA) clinical practice guidelines include community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP), and ventilator-associated pneumonia (VAP; Kalil et al., 2016; Metlay et al., 2019). CAP is any type of pneumonia contracted outside of a health care setting. CAP is one of the most common diagnoses in the US, responsible for more than 45 million outpatient and emergency department visits annually (Ramirez, 2024). HAP occurs 48 hours or more after hospital admission (it is not present on admission) in a non-intubated patient. VAP is a subset of HAP that develops 48 to 72 hours after tracheal intubation or within 48 hours of extubation. VAP is a preventable and costly complication of mechanical ventilation, accounting for 22% of all hospital-acquired infections. VAP is estimated to occur in 10% to 20% of patients receiving mechanical ventilation for more than 48 hours. While all-cause mortality estimates for VAP patients range from 20% to 50%, the direct mortality rate for VAP was recently estimated at 13%. Studies also estimate that VAP prolongs the hospital length of stay by 11.5 to 13.1 days, extends ventilation time by 7.6 to 11.5 days, and increases costs by approximately $40,000 per patient (Ignatavicius & Workman, 2018; Kalil et al., 2016; Metlay et al., 2019; Sattar & Sharma, 2023; Shebl & Gulick, 2023; Wu et al., 2019).

The term health care-associated pneumonia (HCAP) was introduced in the 2005 version of the ATS/IDSA clinical practice guidelines to denote pneumonia contracted from a health care facility such as long-term care, skilled nursing facility, dialysis center, or outpatient clinic. HCAP was considered a distinct clinical entity to identify patients at higher risk of acquiring antibiotic-resistant pathogens. In an effort to minimize patient harm and exposure to unnecessary antibiotics and reduce antibiotic resistance, the updated 2016 and 2019 ATS/IDSA guidelines no longer recommend using HCAP as a distinct category. Pneumonia acquired in other health care-related facilities is considered CAP, and a hospital setting is required to classify pneumonia as HAP. The rationale for this change is based on several high-quality studies demonstrating that the factors used to define HCAP do not predict the high prevalence of multidrug-resistant (MDR) pathogens in most settings. Research has shown that the increased use of broad-spectrum antibiotics such as vancomycin (Vancocin) and antipseudomonal β-lactams has not led to an improvement in patient outcomes. Despite these changes, some research continues to utilize HCAP. In contrast, other sources include both HAP and VAP under the category of HCAP, making some data and statistics more complex and problematic to extrapolate accurately (Kalil et al., 2016; Metlay et al., 2019; Sattar & Sharma, 2023).

There are various etiologies of pneumonia, and research has demonstrated that less than 10% of pneumonia cases have a single cause. In the US, CAP is most commonly caused by S. pneumoniae. Other common etiologies include H. influenzae, M. catarrhalis, and S. aureus. Atypical bacteria causes include legionella and M. pneumoniae. Viral etiologies include RSV, influenza A and B, acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and rhinoviruses. Fungal etiologies typically occur in immunocompromised states such as organ transplant recipients, and the most common include histoplasma, coccidioides, and blastomyces. 

HAP and VAP have overlapping etiologies. The most common causes include gram-positive cocci such as S. aureus, methicillin-resistant S. aureus (MRSA), S. pneumoniae, H. influenzae, and gram-negative bacilli such as Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumonia. The most important pathogens causing VAP are P. aeruginosa, S. aureus, and MRSA. Sensitivity testing should be performed consistently with bacterial cultures, as MDR organisms associated with VAP are of concern (Jain et al., 2023; Kalil et al., 2016; Klompas, 2023a; Metlay et al., 2019; Ramirez, 2024; Sattar & Sharma, 2023; Shebl & Gulick, 2023; Wu et al., 2019).

Risk Factors 

There are several risk factors for pneumonia, with age ranking among the highest. Children younger than 5 years and adults 65 years and older are the most susceptible. People who have chronic health conditions such as chronic obstructive pulmonary disease (COPD), emphysema, a weakened immune system, diabetes, or heart disease are at increased risk (National Heart, Lung, and Blood Institute, 2022a). Some risk factors may vary depending on the setting in which the pneumonia was contracted. For CAP, specific risk factors include lack of pneumococcal vaccination for protection against S. pneumoniae, pneumococcal vaccination more than five years ago, lack of influenza vaccination, recent exposure to a respiratory virus such as influenza, alcohol use disorder (AUD), smoking, and exposure to secondhand smoke (Ignatavicius & Workman, 2018; Ramirez, 2024).

Risk factors for HAP include chronic lung disease, gram-negative colonization of the upper gastrointestinal (GI) tract, altered level of consciousness, aspiration, poor nutritional status, paralysis, immunocompromised status, use of medications that increase gastric pH such as histamine-2 antagonists (H2 blockers), or alkaline tube feedings. Factors that increase a patient's risk for aspiration include dysphagia, altered mental status, drug abuse/AUD, gastroesophageal reflux, and seizure disorders (Sattar & Sharma, 2023). The presence of a nasogastric (NG) tube, endotracheal tube (ETT), and tracheostomy also heighten the risk for HAP. Mechanical ventilation is the primary risk factor for VAP, especially if it is indicated for acute respiratory distress syndrome (ARDS; Ignatavicius & Workman, 2018; Klompas, 2023b; Sattar & Sharma, 2023; Sethi, 2024).

Endotracheal intubation and mechanical ventilation are the most significant risk factors for VAP. An ETT or tracheostomy tube bypasses the body's normal filtering process and provides direct access for pathogens to enter the lower respiratory system. An artificial airway will be colonized with bacteria within 48 hours, provoking pneumonia development. Risk factors for VAP may be separated into three categories: host-related, device-related, and personnel-related. Host-related risk factors include previous hospitalization and pre-existing conditions such as immunosuppression, COPD, ARDS, malnutrition, chronic renal failure, and anemia. Host-related factors also involve the patient's body positioning, advanced age, decreased level of consciousness, multiple or prolonged intubations, receipt of blood transfusions, and certain medications (sedatives, opioids, muscle relaxants, broad-spectrum antibiotics, and glucocorticoids). Supine positioning facilitates pulmonary aspiration and should be avoided, as secretions will pool above the cuff of the ETT (Ignatavicius & Workman, 2018; Klompas et al., 2022; Klompas, 2023b; Sattar & Sharma, 2023; Sethi, 2024).

Device-related risk factors come from the equipment that is being used during ventilation. VAP is a risk for all patients using mechanical ventilation, and rates increase the longer the patient is intubated. Other device-related factors include ETTs, frequent ventilator circuit changes, and NG or orogastric tubes. Low-pressure cuffs can allow micro-aspiration of fluids or leakage of bacteria into the trachea, so a cuff pressure of 20 to 30 cm H₂O should be maintained. Drainage of subglottic secretions and the application of positive end-expiratory pressure (PEEP) may also reduce the risk of aspiration. According to the CDC (2024b), PEEP is "a technique used in respiratory therapy in which airway pressure greater than atmospheric pressure is achieved at the end of exhalation by the introduction of a mechanical impedance to exhalation" (p. 10-7). PEEP is one of the primary parameters that can be adjusted in patients on mechanical ventilation depending on the patient's oxygenation needs. Orogastric and NG tubes disrupt the gastroesophageal sphincter and provoke reflux, which increases a patient's risk of VAP.

Personnel-related risk factors include insufficient handwashing, not changing gloves between patient contacts, and not wearing appropriate personal protective equipment when caring for patients with MDR infections. Poor handwashing before suctioning or manipulating the ventilator circuit increases the likelihood of cross-contamination between patients (Klompas et al., 2022; Klompas, 2023b; Osti et al., 2017).

Patient History

              A combination of patient history, physical examination, and diagnostic findings are required to support a diagnosis of pneumonia. A thorough patient history for suspected pneumonia should include an exploration of all potential risk factors, including the patient's age, diet, exercise habits, sleep routine, social environment, use of a tracheostomy or NG tube, and current or historical use of tobacco, alcohol, or recreational drugs. It is important to ask about past respiratory illnesses, recent exposure to individuals with known or suspected influenza or pneumonia, and influenza, pneumococcal, and COVID-19 vaccination status. Clinicians should inquire about recent travel, as L. pneumophila, Blastomyces dermatitidis, coccidioides, hantavirus, Middle East respiratory syndrome, and avian influenza can cause pneumonia in national and international travelers. Recent travel aboard a cruise ship may indicate L. pneumophila (Grief & Loza, 2018; Ignatavicius & Workman, 2018; Ramirez, 2024).

              Eliciting a patient history of risk factors, behaviors, and environmental exposures can help establish potential pathogens and etiologies. A history of asthma, COPD, immunodeficiency, and tobacco use can indicate an H. influenzae infection. Contaminated air conditioners and water systems can harbor L. pneumophila, causing pneumonia, often referred to as Legionnaires' disease. Crowded spaces—such as jails, dorms, and shelters—can expose a person to S. pneumoniae, Mycobacterium tuberculosis (TB), M. pneumoniae, and Chlamydia trachomatis. Animals, particularly cats, sheep, and cattle, can expose patients to Coxiella burnetii. Birds like chickens, turkeys, and ducks can expose patients to C. psittaci. In patients with chronic respiratory diseases, the history should include the use of respiratory equipment within the home, including the cleaning and storing of this equipment (Grief & Loza, 2018; Ignatavicius & Workman, 2018; Sattar & Sharma, 2023).

Signs and Symptoms

The most common clinical presentation of pneumonia includes fever, dyspnea, shortness of breath or difficulty breathing, and cough. The cough may be nonproductive or productive (phlegm or sometimes blood). Generalized symptoms such as fatigue, chills, sweating, myalgias (muscle pain), anorexia (loss of appetite), and headache may also be present (Radiologyinfo.org, 2023; Sattar & Sharma, 2023). In patients who present with coughing, the probability of pneumonia is only 5%. If they do not have changes in blood pressure (BP), heart rate (HR), or respiratory rate (RR), the probability declines to 1% (Grief & Loza, 2018). Patients with severe coughing may report chest muscle weakness. Some patients will demonstrate findings that indicate damage to the underlying pulmonary tissue. Pleuritic chest pain can be sharp, stabbing, burning, intense, or sudden and occurs with respiration, especially inspiration. Pleuritic pain is caused by inflammation of the underlying parietal pleura. Coughing is due to fluid accumulation in the receptors of the trachea, bronchi, and bronchioles. Purulent, bloody, or rust-colored sputum is due to the inflammatory process, which causes fluid from the pulmonary capillaries and red blood cells to move into the alveoli. Confusion manifests earlier in older patients with pneumonia. Patients who live in nursing homes are immunocompromised or are of advanced age typically display fewer symptoms, so pneumonia should be suspected even without overt symptoms (Grief & Loza, 2018; Ignatavicius & Workman, 2018; Radiologyinfo.org, 2023; Sattar & Sharma, 2023).

Physical Exam

Vital signs should be compared to the patient's baseline values. Tachypnea (increased RR above 18/min) and dyspnea can result from the stimulation of chemoreceptors in pneumonia, but anxiety and pain can also contribute to these manifestations. Hypotension is common in patients with pneumonia due to vasodilation and dehydration, especially in older adults. Fevers manifest when phagocytes release pyrogens and cause the hypothalamus to increase body temperature above 100.4° F (38° C). Tachycardia (HR above 100/min) is often seen in patients with pneumonia. A rapid, weak pulse can indicate hypoxemia (deficiency in the amount of oxygen reaching the tissues), dehydration, sepsis, or septic shock. Oxygen saturation (SpO₂ or pulse oximetry) should be assessed to evaluate for hypoxemia (low level of oxygen in the blood). Cardiac tissue hypoxia can cause dysrhythmias (abnormal cardiac rhythm). A decreased body temperature below 95° F (35° C) or bradycardia (HR below 60/min) may also indicate pneumonia, sepsis, or shock (Grief & Loza, 2018; Ignatavicius & Workman, 2018; Sattar & Sharma, 2023).

              Individuals with pneumonia may appear flushed, anxious, or cyanotic. The patient's breathing pattern should be carefully observed, as they may demonstrate abnormal respiratory movement and accessory muscle use. Labored breathing occurs in response to decreased lung compliance. Hypoxia can cause patients to feel uncomfortable in a reclining position, prompting them to sit upright or lean forward while sitting and place their hands on their knees, referred to as the tripod position. On auscultation of the lungs, rales (short, high-pitched, intermittent crackles most often heard in the lung bases) can be heard when fluid is in the alveolar and interstitial areas. Breath sounds may also be diminished. Wheezing (a high-pitched, coarse whistling sound) may be heard if exudate, mucus, or inflammation narrows the airways. Over areas of density or consolidation, bronchial breath sounds (high-pitched and hollow or tubular, as would typically be heard over the central airways) may be heard due to sound transmission from the trachea. A pleural friction rub (a raspy, grating, or creaky sound due to inflammation within the pleural cavity) may be audible (Ignatavicius & Workman, 2018; Sattar & Sharma, 2023).

Egophony can be assessed by asking the patient to say the letter "e" while auscultating with a stethoscope. The sound being audibly altered, becoming more high-pitched, nasal, and sounding more like an "a," indicates potential consolidation. Similarly, whispered pectoriloquy can be assessed by asking the patient to whisper "99" several times. If the patient can be heard clearly, this indicates potential consolidation. Tactile fremitus (palpable vibration of the chest wall with breathing) will be increased over pneumonia-affected regions, and chest percussion will be flat or dulled over consolidated areas. Chest expansion may be diminished or asymmetrical during inspiration. Tracheal deviation and lymphadenopathy may be evident on the exam (Grief & Loza, 2018; Ignatavicius & Workman, 2018; Sattar & Sharma, 2023).

Atypical pneumonia can cause clusters of specific clinical manifestations, which may help identify the underlying etiology. Several of these are outlined below.

• Rigors (excessive shivering due to a steep rise in body temperature and often accompanied by a feeling of cold and profuse sweating) and rust-colored sputum are seen more frequently with pneumococcal pneumonia (caused by S. pneumoniae).
• P. aeruginosa or H. influenzae are associated with green sputum.
• Klebsiella pneumoniae is associated with "red currant jelly" sputum.
• Foul-smelling and bad-tasting sputum or a recent history of dental infection is associated with anaerobic bacteria.
• Legionnaires' disease often causes alterations in mental status, GI symptoms, and bradycardia.
• Aspiration pneumonia is associated with an impaired gag reflex.
• Nocardia, a gram-positive bacterium found in the water and soil, will often cause cutaneous nodules.
• Bullous myringitis (bullae or vesicles found on the tympanic membrane) can accompany mycoplasma (Sattar & Sharma, 2023).

Pneumonia Severity Scale

Pneumonia severity scales assist in determining disease severity and optimal treatment setting and predicting patient mortality. The most commonly used scales include the Pneumonia Severity Index (PSI) and the CURB-65. Both scales reasonably predict 30-day mortality, but the PSI is more accurate and better validated. The PSI coalesces a patient's demographics, comorbidities, physical examination, and laboratory values, yielding a score that determines the severity of pneumonia. The patient's score is then used to assign them a risk class that determines inpatient or outpatient treatment (Ignatavicius & Workman, 2018; Murillo-Zamora et al., 2018; Patel & Makwana, 2021; Ramirez, 2024).

Diagnostic Imaging

The most common diagnostic tool for pneumonia is a chest x-ray, which will typically demonstrate new or worsening pulmonary infiltrates. However, pneumonia-related changes may not be seen on x-ray until 2 or more days after symptom onset. Consolidation creates an opaque area of increased density on a chest x-ray. The increased density can affect a lung segment, an entire lobe, an entire lung, or both lungs. A chest x-ray is essential for a pneumonia diagnosis in older adults since clinical manifestations can be vague. Two-view chest x-rays should be obtained in patients with appropriate indications, including posteroanterior and lateral views (Ignatavicius & Workman, 2018; Metlay et al., 2019).

Chest x-rays are recommended in patients with abnormal vital signs (a temperature greater than 100° F [37.8° C], HR greater than 100/min, or RR greater than 20/min) and in the presence of crackles or diminished lung sounds in patients without asthma. The ATA/IDSA guidelines state that infiltrates on an x-ray can confirm the diagnosis of pneumonia and exclude other possible causes of symptoms, such as bronchitis. If the physical exam indicates pneumonia but no infiltrates are seen on the chest x-ray, the clinical findings should be used to determine treatment and imaging studies should be repeated in 24 to 48 hours (Kalil et al., 2016; Metlay et al., 2019). According to Grief & Loza (2018), 1 in 10 patients admitted to a hospital with symptoms of pneumonia and a negative chest x-ray will develop evidence of pneumonia on repeat x-rays within 72 hours. Abnormal findings on chest x-rays in patients with pneumonia include lobar consolidation (usually indicative of a typical bacterial pathogen), interstitial infiltrates (infiltrates located within the connective tissue surrounding the air spaces), or cavitation (thick-walled, gas-filled cavities in the lung that may have a visible fluid level). Cavitary pneumonia may indicate an underlying etiology of TB, nocardia, or a fungal pathogen (Ramirez, 2024). If a patient with pneumonia has symptoms that improve within 5 to 7 days of treatment, follow-up chest x-rays are not routinely recommended (Metlay et al., 2019).

A computed tomography (CT) scan of the chest may be indicated for selected patients with a negative chest x-ray. CT provides an enhanced image showing the finer details within the lungs and can detect pneumonia that is more difficult to identify on chest x-ray. CT chest scan is particularly recommended in immunocompromised patients, those with emphysema and other underlying lung conditions, and those exposed to epidemic pathogens such as L. pneumophila. A CT scan shows the airway in greater detail and can help determine if pneumonia may be related to a problem within the airway. A CT scan can also show complications of pneumonia, such as abscesses, pleural effusions, and lymphadenopathy (enlarged lymph nodes). However, CT chest imaging is costly, and there is no high-quality or direct evidence to support its routine use in patients with pneumonia (Radiologyinfo.org, 2023; Ramirez, 2024).

The Clinical Practice Guidelines for the management of CAP in infants and children older than 3 months of age were published in 2011 and are still used in clinical practice today. However, there is an ongoing update (guidelines in development) estimated to be published by the end of 2024 (Bradley et al., 2011). For children receiving inpatient care for pneumonia, two-view chest x-rays with posteroanterior and lateral views should be obtained to document the presence, size, and character of infiltrates. Repeated follow-up chest x-rays are not routinely required. Still, they should be performed for children who deteriorate or do not demonstrate clinical improvement within 48 to 72 hours after starting antibiotic therapy. While routine chest x-rays are not necessary to confirm all suspected pneumonia diagnoses in children in the outpatient setting, two-view chest x-rays should be obtained for pediatric patients with hypoxemia or respiratory distress. Chest x-rays are also indicated for pediatric patients who fail initial antibiotic treatment or have suspected complications of pneumonia. For patients with recurrent pneumonia, follow-up chest x-rays should be obtained (Bradley et al., 2011; Tannous et al., 2020).

 

Laboratory Assessments

For patients with confirmed or suspected mild pneumonia, sputum and blood cultures are not recommended for routine outpatient use. Sputum is often obtained in the inpatient setting for Gram stain, culture, and sensitivity testing. However, the offending organism is not identified in many cases. Although a sputum sample can be obtained relatively easily from patients who can cough into specimen containers, these specimens are contaminated with upper airway organisms. Patients who are extremely ill or unable to cough for collection may need suctioning to obtain a sputum sample (Ignatavicius & Workman, 2018; Metlay et al., 2019). There are several steps that the medical team can take to optimize the quality of a sputum sample: The specimen should be obtained before antibiotic administration. The mouth should be rinsed before expectoration. The patient should avoid eating or drinking for 1 to 2 hours before expectoration, and the specimen should be inoculated onto the culture media immediately after collection (Boruchoff & Weinstein, 2024).

The 2019 ATS/IDSA guidelines recommend Gram staining and culturing (both blood and sputum cultures) for hospitalized patients with HAP or severe CAP with risk factors for MRSA and P. aeruginosa, as well as those being empirically treated for possible infections with these pathogens. Cultures are not routinely recommended for hospitalized patients with mild to moderate CAP. Risk factors for MRSA and P. aeruginosa include a history of respiratory infections with MRSA or P. aeruginosa, hospitalized patients who have received parenteral antibiotics in the last 90 days, and those on mechanical ventilation. Endotracheal aspirates yield better samples of microbiological organisms than standard sputum cultures (Boruchoff & Weinstein, 2024; Bradley et al., 2011; Metlay et al., 2019; Ramirez, 2024).

Blood cultures are not routinely performed for children with pneumonia who are fully immunized and receiving outpatient care. Blood cultures should be obtained when a child fails to demonstrate clinical improvement with treatment within 48 hours or demonstrates progressive symptoms or clinical deterioration after starting antibiotic therapy. For children admitted for inpatient treatment of suspected moderate to severe bacterial pneumonia, blood cultures and sputum cultures should be obtained. If a child improves on appropriate antimicrobial therapy, a positive blood culture should not prevent discharge, especially if a follow-up visit with a health care provider is scheduled. Repeat blood cultures are unnecessary if the child demonstrates clear clinical improvement unless the blood culture shows bacteremia due to S. aureus. Testing (such as urine antigen) for pneumococcal infections is not recommended in children, as false-positive results are common (Bradley et al., 2011).

Fiber optic bronchoscopy for microbiologic testing can be considered for hospitalized and severely ill patients if the potential benefits of this testing, such as confirmation of microbiologic diagnosis, outweigh the risks. Risks include bleeding, pneumothorax, need for intubation, and bronchospasm. A bronchoscopy specimen should be sent for aerobic culture, L. pneumophila culture, fungal stain/culture, and testing for respiratory viruses such as influenza, adenovirus, parainfluenza, RSV, and human metapneumovirus (Ramirez, 2024). This specimen may be obtained via bronchoalveolar lavage, routine brushing, washing, or protected specimen brushing with a double-sheathed catheter to minimize contamination. It is considered most useful in patients with an underlying etiology of TB, Pneumocystis jirovecii, fungal or viral pathogens, or noninfectious cases such as malignancy (Boruchoff & Weinstein, 2024).

More invasive tests, such as transtracheal aspiration and direct needle aspiration, are rarely performed on patients with pneumonia. Transtracheal aspiration involves using a large (15-gauge) needle to access the trachea by entering approximately 0.4 in (1 cm) beneath the cricoid cartilage. The access needle is then replaced with a catheter attached to a syringe. The patient is encouraged to cough while suction is applied to the attached syringe. A sterile saline wash can also be injected to obtain a sample for culture/sensitivity testing. Thoracentesis (fluid removal from the chest cavity) may assist patients who are suffering from accompanying pleural effusions (Ignatavicius & Workman, 2018; Mohanty et al., 2017; Radiologyinfo.org, 2023).

A complete blood count (CBC) should be obtained in hospitalized patients to assess for an elevated WBC count (leukocytosis), a common finding among most patients with pneumonia, except in older adults (Ignatavicius & Workman, 2018). Specifically, leukocytosis with a leftward shift is expected. A leftward shift refers to an increase in the number of immature WBCs. Arterial blood gas analysis determines the patient's baseline arterial oxygen and CO₂ levels. Serum lactate levels are recommended to evaluate for possible sepsis. Serum electrolytes, blood urea nitrogen (BUN), and creatinine levels should be used to assess fluid status and organ function. Labs such as an erythrocyte sedimentation rate, C-reactive protein (CRP), or serum procalcitonin are often elevated in pneumonia patients. These lab values should not be used to determine whether pneumonia has a bacterial or viral origin, though procalcitonin is specific primarily to bacterial infections (Ignatavicius & Workman, 2018; Ramirez, 2024). Empiric antibiotic therapy should be initiated in patients with clinical features and radiographic findings consistent with pneumonia, regardless of serum procalcitonin results. These labs also indicate the clinical response to therapy in patients with moderate to severe pneumonia who require hospitalization (Metlay et al., 2019).

Routine laboratory testing is not necessary for all pediatric pneumonia patients with suspected CAP managed in the outpatient setting, as an elevated WBC count does not reliably distinguish bacterial from viral pneumonia. However, in those with severe disease, a CBC can provide useful information for clinical management, such as the presence of anemia or thrombocytopenia. These findings can help guide therapeutic interventions and potentially heighten suspicion of hemolytic-uremic syndrome, a rare complication of pneumococcal pneumonia in this population (Bradley et al., 2011). Further, children with severe disease and those who appear toxic should have additional testing, including an electrolyte panel, liver function tests, a renal panel, and blood cultures (Ebeledike & Ahmad, 2023).

              Patients presenting with weight loss, persistent coughing, night sweats, and hemoptysis should also be tested for TB. Patients who immigrated from countries with TB outbreaks, reside in homeless shelters, inject illicit drugs, or have HIV should also be considered at high risk for TB (Grief & Loza, 2018). Some bacteria will demonstrate specific biochemical evidence found in laboratory evaluation. An example of this is L. pneumophila, which can present with hyponatremia and microhematuria (Sattar & Sharma, 2023). Immunocompromised patients should be tested for opportunistic infections such as P. jirovecii, fungal or parasitic infections, and less common viral pathogens such as cytomegalovirus (Ramirez, 2024).

              During influenza season, patients with CAP or suspected CAP should be tested for influenza with a rapid molecular assay (nucleic acid amplification test). The rapid molecular assay is preferred over a rapid influenza diagnostic test (antigen test). During periods of lower influenza activity in a community, influenza testing can be considered but is not recommended. Testing for influenza and other respiratory viruses should be used routinely to evaluate children with suspected pneumonia. For children with positive influenza tests, antibacterial therapy is not necessary unless a bacterial co-infection is suspected. Antiviral agents should be used according to the current guidelines for pediatric influenza patients (Bradley et al., 2011; Metlay et al., 2019).

CAP Management

              The medical management and treatment of pneumonia depend on the type and severity of the illness. Pneumonia, especially CAP, can be treated in the outpatient setting most of the time. The previously discussed severity assessment tools can help determine if a patient requires hospitalization. There are separate guidelines and recommendations for the inpatient treatment of pneumonia (Metlay et al., 2019).

 

Outpatient Pediatric Treatment

Antimicrobial therapy is not always required for preschool-aged patients with pneumonia, as these children often experience pneumonia caused by viral pathogens. If children need antibiotic therapy, amoxicillin (Amoxil) should be used as first-line treatment for healthy, fully immunized infants, children, and adolescents with mild to moderate pneumonia. Amoxicillin (Amoxil) generally provides appropriate coverage for S. pneumoniae, the most common bacterial pathogen. As outlined in Table 1, alternatives include second- or third-generation cephalosporins such as cefpodoxime (Vantin), cefuroxime (Zinacef), and cefprozil (Cefzil). Oral levofloxacin (Levaquin) or linezolid (Zyvox) can also be used. Macrolide antibiotics (azithromycin [Zithromax], erythromycin [Erythrocin], and clarithromycin [Biaxin]) should be used to treat children with pneumonia that may be caused by atypical pathogens such as M. pneumoniae, C. pneumoniae, and C. trachomatis (Bradley et al., 2011). Since atypical pneumonia is common in young infants up to 3 months old, they should be hospitalized and given additional antibiotic treatment with erythromycin (Erythrocin) or clarithromycin (Biaxin; Ebeledike & Ahman, 2023). Longer treatment courses such as antibiotics lasting 10 days have been studied the most, but shorter periods may be effective in those with mild disease (Bradley et al., 2011; Kowalska-Krochmal & Dudek-Wicher, 2021).

Table 1

Preferred and Alternate Oral Agents for Susceptible Microorganisms in Pediatric Pneumonia

 

Pathogen	Preferred Oral Agent	Alternate Oral Agent
S. pneumoniae	Amoxicillin (Amoxil)	2nd- or 3rd-generation cephalosporin or levofloxacin (Levaquin) or linezolid (Zyvox)
S. pneumoniae	Levofloxacin (Levaquin) or linezolid (Zyvox)	Clindamycin (Cleocin)
GAS	Amoxicillin (Amoxil) or penicillin V	Clindamycin (Cleocin)
S. aureus (methicillin-susceptible)	Cephalexin	Clindamycin (Cleocin)
MRSA (clindamycin [Cleocin]-susceptible)	Clindamycin (Cleocin)	Linezolid (Zyvox)
MRSA (clindamycin [Cleocin]-resistant)	Linezolid (Zyvox)	None available
H. influenzae	Amoxicillin (Amoxil) or amoxicillin/clavulanate (Augmentin) if ß-lactamase-producing	Cefdinir, cefixime (Suprax), cefpodoxime, or ceftibuten (Cedax)
M. pneumoniae, C. pneumoniae, or C. trachomatis	Azithromycin (Zithromax)	Clarithromycin (Biaxin) or erythromycin (Erythrocin); children over 7 may use doxycycline (Vibramycin); adolescents with skeletal maturity may use levofloxacin (Levaquin) or moxifloxacin (Avelox)

(Bradley et al., 2011; Kowalska-Krochmal & Dudek-Wicher, 2021)

Outpatient symptom management is critical and includes antipyretics for fever and fluids to treat and prevent dehydration. Children who fail to respond to antibiotics and supportive treatments within 72 hours should be re-assessed for complications. Clinicians should pay close attention to potential complications, especially in pediatric outpatients returning for repeat evaluation (Ebeledike & Ahmad, 2023).

Inpatient Pediatric Treatment

Guidelines recommend hospitalization in infants younger than 90 days old (or those with bacterial CAP less than 6 months old), patients with atypical or highly virulent pathogens such as MRSA, and those with moderate to severe CAP based on clinical presentation (respiratory distress and hypoxemia [SpO₂ less than 90%]). In addition, hospitalization and intravenous (IV) antibiotics are typically required for immunocompromised children and those with underlying chronic diseases such as sickle cell anemia, cardiac disease, and cystic fibrosis. Hospital-based care is also recommended if there is concern regarding the caregiver's ability to provide sufficient supervision and comply with the prescribed treatment plan. Pulse oximetry should be monitored in all children hospitalized with pneumonia. Admission to an ICU is recommended for patients who require positive pressure ventilation (either invasive or noninvasive), have impending respiratory failure (SpO₂ less than 92% on 0.5 [50%] fraction of inspired oxygen [FiO₂]), demonstrate sustained tachycardia, hypotension, altered mental status due to hypercarbia or hypoxemia, or need vasopressor support to maintain perfusion. According to the CDC (2024b), FiO₂ is defined as the fraction of oxygen in inspired gas. In patients receiving mechanical ventilation, FiO₂ is one of the primary parameters that can be adjusted depending on the patient's oxygenation needs. The severity scores described within this activity should not be used as the sole determining factor regarding the optimal treatment setting for pediatric patients. Still, they may be included as a component of the decision-making process along with clinical, laboratory, and imaging findings (Bradley et al., 2011; Ebeledike & Ahmad, 2023).

If IV antibiotics are required for healthy, fully immunized pediatric patients due to a lack of clinical improvement within the first 24 to 72 hours, the preferred treatment for S. pneumoniae is ampicillin (Omnipen) or penicillin unless the sensitivity testing indicates that the MIC for penicillin is greater than 4 mcg/mL. In that case, alternatives include ceftriaxone (Rocephin) or cefotaxime (Claforan). These third-generation cephalosporins should also be used for pediatric patients who are not fully immunized, live in areas with a high rate of penicillin resistance, have life-threatening infections, or develop empyema. Combination therapy with an oral or parenteral macrolide and a ß-lactam antibiotic (penicillins, cephalosporins, and carbapenems) may be indicated for pediatric patients with pneumonia caused by an atypical pathogen. Vancomycin (Vancocin) or clindamycin (Cleocin) should be administered with a ß-lactam (cefazolin [Ancef], oxacillin [Bactocill]) for infections caused by S. aureus. Prescribers should be aware that clindamycin (Cleocin) resistance has increased in some geographic regions among S. pneumoniae and S. aureus. While treatment courses for antibiotics lasting 10 days have the highest level of evidence, infections caused by MDR pathogens may require prolonged treatment. Pediatric patients receiving appropriate therapy should show clinical and laboratory improvements within 48 to 72 hours of antibiotic initiation. For pediatric patients who demonstrate signs of clinical deterioration after admission or no improvement within 48 to 72 hours, further investigation is needed to determine the reason for the lack of response and whether higher-level care is necessary. Table 2 outlines the antibiotic agents by susceptible microorganisms (Bradley et al., 2011).

Table 2

Preferred and Alternate Parenteral Agents for Susceptible Microorganisms in Pediatric Pneumonia

 

Pathogen	Preferred Parenteral Agent	Alternate Parenteral Agent
S. pneumoniae	Ampicillin (Omnipen) or penicillin G	Ceftriaxone (Rocephin) or cefotaxime (Claforan) or clindamycin (Cleocin) or vancomycin (Vancocin)
S. pneumoniae	Ceftriaxone (Rocephin)	Ampicillin (Omnipen) or levofloxacin (Levaquin) or linezolid (Zyvox) or clindamycin (Cleocin) or vancomycin (Vancocin)
GAS	Penicillin or ampicillin (Omnipen)	Ceftriaxone (Rocephin) or cefotaxime (Claforan) or clindamycin (Cleocin) or vancomycin (Vancocin)
S. aureus (methicillin-susceptible)	Cefazolin (Ancef) or oxacillin (Bactocill)	Clindamycin (Cleocin) or vancomycin (Vancocin)
MRSA (clindamycin [Cleocin]-susceptible)	Vancomycin (Vancocin) or clindamycin (Cleocin)	Linezolid (Zyvox)
MRSA (clindamycin [Cleocin]-resistant)	Vancomycin (Vancocin)	Linezolid (Zyvox)
H. influenzae	Ampicillin (Omnipen) or ceftriaxone (Rocephin) or cefotaxime (Claforan)	Ciprofloxacin (Cipro) or levofloxacin (Levaquin)
M. pneumoniae, C. pneumoniae, or C. trachomatis	Azithromycin (Zithromax)	Erythromycin lactobionate or levofloxacin (Levaquin)

(Bradley et al., 2011)

For children with moderate to severe pneumonia during influenza season and suspected influenza co-infection, antiviral therapy should be administered as soon as possible. Oseltamivir (Tamiflu) is the first-line recommended agent and is available in liquid or tablet form. Pediatric dosing recommendations are based on the infant or child's age and weight and are given. Other medications include zanamivir (Relenza), amantadine (Symmetrel), and rimantadine (Flumadine). Amantadine (Symmetrel) and rimantadine (Flumadine) are only recommended for prophylactic treatment during influenza seasons in which most influenza A strains are determined to be susceptible to adamantine (Symmetrel) due to a rapid emergence of resistance. For patients who require adamantane (Symmetrel) therapy, a course of 7 days is recommended or until signs and symptoms have resolved for 24 to 48 hours. Early antiviral treatment provides the maximum benefit, so treatment should not be delayed while awaiting the confirmation of a positive influenza test result (Bradley et al., 2011).

              In hospitalized patients, repeat chest x-rays should be performed for children who do not demonstrate clinical improvement or deteriorate within 48 to 72 hours after starting antibiotic therapy to assess the progression of pneumonia or the development of complications. Repeat sputum cultures may be needed to identify whether the original pathogen persists or if it has developed resistance to the antimicrobial; this can also reveal a new secondary infection. For seriously ill children on mechanical ventilation, a percutaneous lung aspiration or open lung biopsy may be required if previous cultures did not indicate a microbiologic etiology (Bradley et al., 2011).

              Pediatric patients may be eligible for discharge if they have demonstrated an overall clinical improvement in activity level, appetite, and absence of fever for at least 12 to 24 hours. Patients should consistently demonstrate a SpO₂ over 90% on room air for at least 12 to 24 hours and a stable or returned-to-baseline mental status. For children with a chest tube, discharge is appropriate once the tube has been removed for 12 to 24 hours and there is no evidence of clinical deterioration. Patients should not demonstrate increased labor of breathing, sustained tachypnea, or tachycardia to be eligible for discharge. Documentation should indicate that the patient has tolerated their antimicrobial and oxygen regimens before release. Parents or caregivers should demonstrate an ability to comply with the prescribed antibiotic regimen before discharge. Any issues or concerns about home care, ability to comply with therapy, or availability for follow-up care should be addressed before release. Outpatient parenteral antibiotic therapy is appropriate in patients who no longer require skilled nursing care but need ongoing parenteral treatment. The therapy can be offered through a pediatric home health program or daily intramuscular injections in an outpatient facility. Transitioning pediatric patients to oral antibiotics before discharge is preferred when possible (Bradley et al., 2011).

Outpatient Adult Treatment

              For healthy adult patients without comorbidities, outpatient monotherapy is recommended with amoxicillin (Amoxil), doxycycline (Vibramycin), or a macrolide antibiotic such as azithromycin (Zithromax) or clarithromycin (Biaxin) if the local pneumococcal resistance is below 25%. Patients with comorbidities are more vulnerable to poor outcomes when initial antibiotic therapy has failed. Thus, if the patient has a chronic disease of the heart, lung, liver, or kidneys, diabetes mellitus, AUD, cancer, or asplenia, combination therapy with either amoxicillin/clavulanate (Augmentin) or a cephalosporin plus either a macrolide or doxycycline (Vibramycin) is recommended. This combination helps target possible MDR organisms, such as S. pneumoniae, in these patients due to their previous exposure to antibiotics or contact with the health care system. Alternately, monotherapy in these patients using a respiratory fluoroquinolone (levofloxacin [Levaquin], ciprofloxacin [Cipro], moxifloxacin [Avelox], gemifloxacin [Factive]) is an acceptable option. Current treatment recommendations outline antibiotic options but do not specify a preference order. However, monotherapy using amoxicillin (Amoxil) in those without comorbidities and monotherapy using a fluoroquinolone in those with comorbidities are both strong recommendations, whereas the remaining regimens were conditional. The antibiotic choice should be based on a risk assessment for the individual patient, such as allergies, cardiac arrhythmias, current medications, vascular disease, and a history of Clostridium difficile. Patients with recent exposure to one class of antibiotics should be given a different class. Macrolide antibiotics should be considered cautiously for patients with cardiac arrhythmias, and fluoroquinolones should be used carefully for those with vascular disorders (Metlay et al., 2019). Table 4/3 summarizes adult outpatient treatment recommendations.

Table 3

 

Recommended Outpatient Treatments for Adults With Pneumonia 

 

Pneumonia with no comorbidities or no risk factors for MRSA and P. aeruginosa (choose 1)		Amoxicillin (Amoxil)
		Doxycycline (Vibramycin)
		Azithromycin (Zithromax)
		Clarithromycin (Biaxin)
		Clarithromycin (Biaxin) extended-release
Pneumonia with comorbidities but no risk factors for MRSA and P. aeruginosa  (1 antibiotic chosen from section A with another from section B or monotherapy with a fluoroquinolone from section C alone)	A	Amoxicillin/clavulanate (Augmentin)
		Cefpodoxime (Vantin)
		Cefuroxime (Zinacef)
	B	Azithromycin (Zithromax)
		Clarithromycin (Biaxin)
		Clarithromycin (Biaxin) ER
		Doxycycline (Vibramycin)
	C	Levofloxacin (Levaquin)
		Moxifloxacin (Avelox)
		Gemifloxacin (Factive)

(Metlay et al., 2019)

              Patients with CAP who are treated in the outpatient setting should be seen for follow-up by their clinician 2 days after starting antibiotic therapy to assess for symptom improvement and the potential development of complications (Sattar & Sharma, 2023). During an ordinary course of pneumonia, tachycardia and hypotension should begin to improve within 2 days of antibiotic initiation. Fever, oxygenation, and tachypnea are expected to improve within 3 days. Most patients typically report feeling better within 3 to 5 days of starting treatment. Coughing, fatigue, and visible infiltrates on chest x-ray can take 2 to 4 weeks to improve, even in mild pneumonia (Gronthoud, 2020). However, in adults whose symptoms have resolved within 5 to 7 days, routine follow-up chest imaging is not advised (Metlay et al., 2019).

Inpatient Adult Treatment

The decision to admit a patient for treatment should be based on a validated severity score described earlier and the patient's overall clinical picture. Patients with a PSI class of III or higher or a CURB-65 score of 2 or higher should be admitted. Generally, a patient with pneumonia and a SpO₂ of less than 92% on room air requires admission to the hospital (Ramirez, 2024). Those with respiratory failure requiring mechanical ventilation or sepsis requiring vasopressor support should be admitted to an ICU, as these are the major criteria for severe pneumonia established by the ATS/IDSA. Otherwise, three minor criteria are required for classification as severe pneumonia, including the following.

• RR greater than 30/min
• partial pressure of arterial oxygen (PaO₂)/FiO₂ ratio less than 250
• multilobar infiltrates on chest imaging (infiltrates involving two or more lobes)
• confusion/disorientation
• uremia (BUN greater than 20 mg/dL)
• leukopenia (WBC less than 4,000 cells/mcL)
• thrombocytopenia (platelets less than 100,000 mm³)
• hypothermia (core temperature less than 96.8° F [36° C])
• hypotension requiring aggressive fluid resuscitation (Metlay et al., 2019)

Clinicians should rely on more than clinical severity to determine the need for inpatient treatment. Underlying health conditions and psychosocial conditions should also be considered, including substance use disorder, tobacco use, cognition, functional status, and the ability to maintain oral intake (Metlay et al., 2019). Hospitalized adults requiring inpatient treatment should receive combination antibiotic therapy, such as a ß-lactam and a macrolide. If combination therapy is not used, monotherapy with a respiratory fluoroquinolone is recommended. An alternative for those unable to tolerate macrolides or fluoroquinolones is dual treatment with a ß-lactam antibiotic and doxycycline (Vibramycin). Antibiotic recommendations for inpatient pneumonia target the most likely pathogens that cause pneumonia. Separate recommendations are made for those who are at risk for infection with MRSA or P. aeruginosa. The highest risk factors for these organisms are a prior diagnosed infection with documented cultures, a recent hospitalization, or recent use of parenteral antibiotics. Hospitalized patients with severe pneumonia should be treated empirically for MRSA or P. aeruginosa if these risk factors are present; blood and sputum Gram stain/cultures should also be performed. Hospitalized patients with a history of MRSA or P. aeruginosa infections should be treated empirically while awaiting culture results, regardless of disease severity. Treatment options for MRSA include vancomycin (Vancocin) or linezolid (Zyvox) (Metlay et al., 2019; Ramirez, 2024).

IV antibiotics should be started as soon as pneumonia is determined to be the appropriate diagnosis, ideally within 4 hours (Metlay et al., 2019; Ramirez, 2024). In a landmark study, Houck and colleagues (2004) retrospectively assessed the data regarding the timing of the initial antibiotic dose in Medicare patients admitted with CAP. They found reduced mortality and length of stay when the initial dose of antibiotics was administered within 4 hours of admission. A loading dose of vancomycin (Vancocin) may be necessary (Klompas, 2024). Treatment options for P. aeruginosa include piperacillin-tazobactam (Zosyn), cefepime (Maxipime), ceftazidime (Fortaz), aztreonam (Azactam), meropenem (Merrem), or imipenem (Primaxin). Table 4 summarizes inpatient recommendations for adults with non-severe CAP, while Table 5 summarizes adults with severe CAP (Metlay et al., 2019; Ramirez, 2024).

Table 4

 

Inpatient Treatment Recommendations for Adults With Non-Severe CAP

 

Diagnosis	Regimen
1) Non-severe pneumonia (a ß-lactam and a macrolide in combination OR a respiratory fluoroquinolone alone)	Ampicillin/sulbactam (Unasyn)
	Cefotaxime (Claforan)
	Ceftriaxone (Rocephin)
	Ceftaroline (Teflaro)
	PLUS
	Azithromycin (Zithromax)
	Clarithromycin (Biaxin)
	Doxycycline (Vibramycin)
	OR
	Levofloxacin (Levaquin)
	Moxifloxacin (Avelox)
2) If recent hospitalization and parenteral antibiotics and locally validated risk factors for MRSA or P. aeruginosa	Obtain cultures but withhold MRSA or P. aeruginosa treatment unless culture results are positive. If rapid nasal polymerase chain reaction testing for MRSA is obtained, withhold treatment for negatives and initiate if positive.
3) If prior respiratory isolation of MRSA or P. aeruginosa	Add coverage for MRSA (vancomycin [Vancocin] or linezolid [Zyvox]) and obtain cultures to inform further treatment OR Add coverage for P. aeruginosa (piperacillin-tazobactam [Zosyn], cefepime [Maxipime], ceftazidime [Fortaz], imipenem [Primaxin], meropenem [Merrem], or aztreonam [Azactam]) and obtain cultures to inform further treatment.

(Metlay et al., 2019)

Table 5

 

Inpatient Treatment Recommendations for Adults With Severe CAP

 

Diagnosis	Regimen
Severe pneumonia (a ß-lactam in combination with a macrolide or a fluoroquinolone)	Ampicillin/sulbactam (Unasyn)
	Cefotaxime (Claforan)
	Ceftriaxone (Rocephin)
	Ceftaroline (Teflaro)
	PLUS
	Azithromycin (Zithromax)
	Clarithromycin (Biaxin)
	Levofloxacin (Levaquin)
	Moxifloxacin (Avelox)
	Doxycycline (Vibramycin)
If recent hospitalization and parenteral antibiotics, locally validated risk factors for MRSA or P. aeruginosa, or prior respiratory isolation of MRSA or P. aeruginosa	Add coverage for MRSA (vancomycin [Vancocin] or linezolid [Zyvox]) and obtain cultures to inform further treatment OR Add coverage for P. aeruginosa (piperacillin-tazobactam [Zosyn], cefepime [Maxipime], ceftazidime [Fortaz], imipenem [Primaxin], meropenem [Merrem], or aztreonam [Azactam]) and obtain cultures to inform further treatment.

(Metlay et al., 2019)

The patient's clinical improvement should guide the duration of antibiotic treatment for CAP, but a minimum of 5 days is recommended. While most patients may reach clinical stability within 48 to 72 hours of antibiotic initiation, treatment should continue for at least 5 days. The same medication or drug class should be used when transitioning from IV to oral antibiotics. For patients with suspected MRSA or P. aeruginosa and those with HAP/VAP, the recommended course of treatment is 7 days (Kalil et al., 2016). Some studies have shown that procalcitonin levels can influence the duration of antibiotic therapy, but concerns persist regarding the use of procalcitonin to determine the duration of treatment. In many studies, the average length of therapy guided by procalcitonin levels was much longer than recommended in the US standards of practice and current guidelines. Procalcitonin levels may not appropriately rise when a patient has a viral and bacterial infection simultaneously. Longer courses of antibiotics are recommended for patients with complications such as meningitis, endocarditis, or infections related to less common pathogens. Routine follow-up chest imaging is not required in hospitalized patients who improve clinically within 5 to 7 days (Metlay et al., 2019).

Patients with aspiration pneumonia should not receive routine anaerobic coverage unless a lung abscess or empyema is suspected or diagnosed. Historically, aspiration pneumonia involved anaerobic organisms in studies. However, more recent studies demonstrate that anaerobes are uncommon in patients with aspiration pneumonia. Routine corticosteroids are not recommended for adult pneumonia infections and should not be used routinely for adults with severe CAP or influenza pneumonia. However, corticosteroids are advised for those with pneumonia compounded by septic shock in accordance with the Surviving Sepsis Campaign recommendations, which are endorsed by ATA/ISDA guidelines (Metlay et al., 2019). While two randomized controlled trials demonstrated reductions in mortality, length of stay, and organ failure using corticosteroids in patients with CAP, other studies have not replicated these findings. The results of these studies are criticized for potentially overestimating the true impact of corticosteroids on treatment outcomes for pneumonia. Corticosteroids carry additional risks and side effects, such as hyperglycemia, increased rehospitalization rates, and potentially increased complications in the first 90 days following treatment. Corticosteroids remain clinically appropriate for COPD, asthma, and autoimmune diseases (Metlay et al., 2019).

Adult patients who are diagnosed with an influenza co-infection should receive antiviral treatment with oseltamivir (Tamiflu). Patients treated in the outpatient setting should receive a prescription for anti-influenza medication regardless of the duration of illness. Treatment with anti-influenza medications is most beneficial within 2 days of symptom onset, but benefits may occur for up to 4 or 5 days after symptoms begin. S. aureus is the most common bacterial infection associated with influenza pneumonia, as well as S. pneumoniae, H. influenzae, and GAS. The same antibiotics recommended as first-line therapy for pneumonia are appropriate for these pathogens (Metlay et al., 2019).

 

Pneumonia Bundles

The British Thoracic Society (2016) proposes a care bundle consisting of four areas to improve care outcomes in patients hospitalized with CAP. The priorities include patient safety, timely antimicrobial prescription, prompt oxygen administration, and a chest x-ray. The CAP bundle is indicated for the inpatient treatment of lower respiratory tract infection with new infiltrates on chest x-ray and no prior hospital admission within the last 10 days. According to the care bundle, patients should have a SpO₂ assessment completed within 1 hour of admission. The goal for patients over 16 years is a SpO₂ of 94% to 98%. If a patient needs supplemental oxygen, it should be prescribed and administered within 1 hour of admission. All patients admitted with suspected CAP should undergo a chest x-ray quickly enough to allow the diagnosis to be confirmed and antibiotics to be prescribed within 4 hours. IV antibiotics should be administered for patients with a CURB-65 score equal to or greater than 3. Antibiotics should be ordered and administered within 4 hours of hospital admission. Similarly, ventilator bundles have been developed to reduce VAP incidence and are discussed in the next section (British Thoracic Society, 2016; Ignatavicius & Workman, 2018).

HAP/VAP Diagnosis and Management 

Diagnosing HAP/VAP is challenging because the clinical findings are nonspecific. Chest x-rays should not be used to diagnose the illness without additional clinical criteria being met, as pulmonary infiltrates can be caused by atelectasis, alveolar hemorrhage, aspiration, ARDS, pulmonary embolism, pulmonary edema, or pulmonary infarction in these patients (Ignatavicius & Workman, 2018). Clinical criteria for the diagnosis of HAP or VAP include the presence of new lung infiltrates on imaging plus clinical evidence that the infiltrates are related to an infectious organism, such as purulent sputum, elevated body temperature (above 100.4° F [38° C]), leukocytosis or leukopenia, and decline in oxygenation (Kalil et al., 2016; Klompas, 2023a; Klompas et al., 2022). Still, no distinct signs or symptoms or any specific combination of these signs have been found to be highly sensitive or specific for diagnosis (Fernando et al., 2020).

Clinicians typically rely on clinical, radiographic, and laboratory indicators to diagnose VAP and initiate empiric antibiotics. Semiquantitative lower respiratory secretion cultures should be obtained before starting antibiotics. Noninvasive sampling of endotracheal aspirates with methods such as protected specimen brush (PSB or bronchoalveolar lavage (BAL) is recommended. Re-evaluation based on lower respiratory tract cultures and serial clinical evaluations should occur within 3 days of antibiotic initiation. PSB and BAL are less sensitive but more specific, with an increased risk of false-negative findings, especially in patients with a recent antibiotic change (within 24 to 72 hours). Therefore, all cultures should be obtained before any change to the antibiotic regimen. Alternatively, a modified clinical pulmonary infection score (CPIS) may be used. This score combines clinical, radiographic, and physiological (PaO₂/FiO₂) data for a subjective score. The modified CPIS does not rely on culture results. A CPIS score of 6 or less for 3 consecutive days is an objective method to identify patients at low risk for early discontinuation of empiric antibiotic treatment. Regardless of the diagnostic approach, all patients with suspected VAP should have extrapulmonary sources of infection excluded (such as a urinary tract infection) and a lower respiratory sample evaluated for culture. Initiation of treatment should not be delayed for diagnostic testing in patients with suspected HAP or VAP who are clinically unstable (Kalil et al., 2016).

              Patients with HAP and mechanically ventilated patients with VAP should be regularly cultured. Noninvasive sampling via endotracheal aspiration with semiquantitative cultures is recommended over invasive sampling methods or quantitative cultures in patients with suspected VAP. The guidelines endorse antibiotic discontinuation if the quantitative culture results are below the diagnostic threshold for VAP (BAL with less than 10⁴ colony-forming units/mL or PSB with less than 10³ colony-forming units/mL) if invasive sampling methods were utilized. Patients with suspected HAP should be treated based on the results of noninvasive sampling (spontaneous expectoration, sputum induction, nasotracheal suctioning) rather than being treated empirically. The clinical criteria described above should be used to decide whether to initiate treatment for HAP/VAP independent of the results of procalcitonin, CRP, soluble triggering receptor expressed on myeloid cells, and CPIS (Kalil et al., 2016).

The CDC (2024b) defines the presence of a ventilator-associated condition (VAC) as at least 2 days of stable or decreasing daily minimum PEEP or FiO₂ followed by a 2-day increase of at least 3 cm H₂O in PEEP or at least 0.2 points (20%) FiO₂. On or after calendar day 3 of mechanical ventilation and within 2 calendar days before or after the onset of worsening oxygenation, the patient meets the following criteria.

• elevated temperature greater than 100.4° F (38° C) or less than 96.8° F (36° C), OR WBC greater than or equal to 12,000 cells/mm³ or less than or equal to 4,000 cells/mm³, and
• a new antimicrobial agent(s) is started and is continued for greater than or equal to 4 days

Infection-related VAC (IVAC) occurs on or after day 3 of mechanical ventilation and within 2 calendar days before or after the onset of worsening oxygenation. In addition, one of the following criteria must be met to support a diagnosis of IVAC (CDC, 2024b).

• Criterion #1: positive culture of one of the endotracheal aspirate, BAL, or PSB specimens, meeting quantitative or semi-quantitative thresholds depending on the specimen source
• Criterion #2: purulent respiratory secretions from the lungs, bronchi, or trachea that contain greater than or equal to 25 neutrophils and less than or equal to 10 squamous epithelial cells and an organism identified from sputum, endotracheal aspirate, BAL, PSB, or lung tissue specimens
• Criterion #3: one of the following positive tests:
  • organisms identified from pleural fluid where the specimen was obtained during thoracentesis or within 24 hours of chest tube placement (pleural fluid specimens collected after a chest tube is repositioned or from a chest tube in place longer than 24 hours are not eligible for possible VAP)
  • lung histopathology (abscess formation, lung parenchyma invasion by fungi, or evidence of infection with the viral pathogens based on results of immunohistochemical assays, cytology, or microscopy)
  • diagnostic test for legionella
  • diagnostic test on respiratory secretions for influenza, RSV, adenovirus, parainfluenza virus, rhinovirus, human metapneumovirus, or coronavirus

Possible VAP is defined as evidence of IVAC in combination with purulent pulmonary secretions based on Gram's stain or pulmonary culture results indicating a pathogen. These definitions and the above criteria are meant to be used for surveillance and quality improvement purposes and not for diagnosis and treatment at the bedside (CDC, 2024b; Klompas et al., 2022).

 

HAP/VAP Treatment

The ADA/ISDA guidelines strongly recommend that hospitals regularly create and disseminate antibiograms to inform empiric regimens with the distribution of pathogens and their susceptibilities within specified units of their facility, particularly the ICU (Kalil et al., 2016). After the initial dosing regimen, antibiotics should be dosed based on pharmacokinetic and pharmacodynamic data, not the manufacturer's prescribing information. Susceptibility cultures should be used to focus or de-escalate antibiotic therapy once available. A total of 7 days of antibiotic treatment is recommended for both HAP and VAP if patients are clinically stable. Support from procalcitonin levels and clinical criteria (not CPIS) can be used to help determine timing beyond that (Kalil et al., 2016). Oral antibiotics should be started once patients are stable clinically and able to tolerate them. A procalcitonin level below 0.25 ng/mL, or a decrease of at least 80% from the peak level, typically indicates that the antibiotic treatment can be safely discontinued in a clinically improving patient (Klompas, 2024).

All empiric regimens for HAP/VAP should include coverage for S. aureus, P. aeruginosa, and other gram-negative bacilli. However, recommendations are based on the patient's risk for MDR pathogens. MDR risk categories are outlined in Table 7/6 (Kalil et al., 2016; Klompas, 2024).

Table 6

Risk Factors for MDR Pathogens

General risk factors for MDR pathogens  (P. aeruginosa, other gram-negative bacilli, MRSA)

IV antibiotic use within 90 days septic shock at the time of VAP ARDS preceding VAP 5 or more days of hospitalization prior to VAP onset acute renal replacement prior to VAP onset

Risk factors specific to MDR P. aeruginosa

VAP treatment in an ICU setting where the prevalence of resistance among gram-negative cultures associated with VAP is greater than 10% treatment in an ICU in which local antimicrobial susceptibility rates among gram-negative bacilli are unknown prior history of colonization with MDR P. aeruginosa from any site, but especially from the respiratory tract structural lung disease (bronchiectasis, cystic fibrosis)

Risk factors specific to MRSA

treatment in a unit where the prevalence of methicillin resistance is unknown or greater than 20% of S. aureus isolates are methicillin-resistant prior history of colonization with MRSA or prior isolation of MRSA on culture from any site, but especially from the respiratory tract

(Klompas, 2024)

Low-risk patients with HAP/VAP with no known general risk factors for MDR pathogens and no increased mortality risk may be treated with a single agent that is effective against both methycillin-susceptible S. aureus (MSSA) and gram-negative bacilli such as piperacillin-tazobactam (Zosyn), cefepime (Maxipime), imipenem (Primaxin), or meropenem (Merrem). Levofloxacin (Levaquin) is another option, particularly if there is suspicion of legionella and local resistance rates of S. aureus, P. aeruginosa, and other gram-negative bacilli to fluoroquinolones are low (Klompas, 2024). Risk factors for MDR gram-negative bacilli increase the risk for extended-spectrum β-lactamase-producing pathogens. According to the 2023 ATS/IDSA guidance on the treatment of antimicrobial-resistant gram-negative infections, patients infected with MDR pathogens have demonstrated better clinical outcomes when treated with carbapenems instead of broad-spectrum antibiotics, such as piperacillin-tazobactam (Zosyn) or cefepime (Maxipine; Tamma et al., 2023).

Empiric coverage for patients with suspected VAP or HAP at increased risk for MDR P. aeruginosa only but without any risk factors for MRSA should include two agents for pseudomonal coverage, ensuring one of those is also active against MSSA. Preferably, a ß-lactam and a non-ß-lactam agent should be selected. A patient with suspected VAP or HAP who is determined to be at increased risk for MRSA only but without any risk factors for MDR P. aeruginosa can be given a single agent for gram-negative coverage in combination with either vancomycin (Vancocin) or linezolid (Zyvox). Providers should avoid combining vancomycin (Vancocin) and piperacillin-tazobactam (Zosyn) due to an increased risk of kidney injury; a cephalosporin can be paired with vancomycin (Vancocin) or piperacillin-tazobactam (Zosyn) with linezolid (Zyvox) instead. A patient with suspected VAP who is at increased risk of MDR infection due to the general risk factors listed in Table 6 should be given three agents total: two agents for pseudomonal coverage, preferably using a ß-lactam and a non-ß-lactam agent, in combination with either vancomycin (Vancocin) or linezolid (Zyvox). This same regimen should be initiated for suspected HAP patients at increased risk of mortality or with risk factors of MDR gram-negative pathogens and MRSA. Once culture sensitivity results are confirmed, empiric treatment for MSSA can often be completed using oxacillin (Bactocill) or cefazolin (Ancef) (Klompas, 2024).

Table 7 outlines the recommendations from the ATA/IDSA guidelines on empiric treatment for VAP in units where MRSA coverage and double antipseudomonal/gram-negative coverage are appropriate. Patients should be given one gram-positive option from Row A, one gram-negative option from Row B, and one gram-negative option from Row C (Kalil et al., 2016).

Table 7

 

ATA/IDSA Empiric Antibiotic Regimen Recommended for HAP/VAP

 

Row A Coverage for gram-positive organisms with MRSA activity	Vancomycin (Vancocin) or linezolid (Zyvox)
Row B Coverage for gram-negative organisms with antipseudomonal activity (β-lactam-based agents)	Piperacillin-tazobactam (Zosyn), cefepime (Maxipime), ceftazidime (Fortaz), imipenem (Primaxin), meropenem (Merrem), or aztreonam (Azactam)
Row C Coverage for gram-negative with antipseudomonal activity (non-β-lactam based agents)	Ciprofloxacin [Cipro], levofloxacin [Levaquin], amikacin [Amikin], gentamicin [Gentak] or tobramycin [Nebcin], colistin [Coly Mycin M], or polymyxin B [Poly Rx]

 (Kalil et al., 2016)

 

Complications

Bacterial pneumonia creates many complications, most commonly coagulopathy, exacerbation of preexisting comorbidities, multiorgan failure, respiratory failure, and sepsis (Sattar & Sharma, 2023). Other complications include:

• cavitation
• destruction of lung parenchyma
• empyema
• pulmonary abscess
• lung fibrosis
• meningitis
• death (Sattar & Sharma, 2023)

About half of HAP patients develop severe complications, such as respiratory failure, septic shock, empyema, renal failure, or pleural effusion. VAP is associated with prolonged

duration of mechanical ventilation, increased ICU length of stay, higher costs, and increased mortality (Fernando et al., 2020). Complications due to pneumonia chiefly affect children, older adults, and patients with comorbidities. Damage to the kidneys, liver, and heart can occur from hypoxia. Abscess formation can perforate the bronchial wall, leading to tissue necrosis (or necrotizing pneumonia). Necrotizing pneumonia is very difficult to treat, potentially requiring surgery to remove the purulent drainage. Sepsis can occur if the pathogen from the lungs escapes into the bloodstream, causing systemic inflammatory response syndrome (Ignatavicius & Workman, 2018; National Heart, Lung, and Blood Institute, 2022a, 2022b).

Antimicrobial treatment for pneumonia can also lead to complications such as C. difficile infection. Fluoroquinolones and broad-spectrum cephalosporins are the most common culprits of C. difficile infections. Cefepime (Maxipime) and imipenem (Primaxin) increase the risk of seizures in those with renal insufficiency. Fluoroquinolones can lead to QT prolongation, tendinitis or tendon rupture, and neurotoxicity (Klompas, 2024).

Non-Resolving Pneumonia

              Although the rate of pneumonia resolution is not clearly defined and often varies based on the underlying cause, pneumonia tends to resolve more slowly in some patients than in others. In these cases, it can be challenging to differentiate between non-resolving pneumonia and a slower recovery process. Most uncomplicated pneumonia cases are expected to see an improvement in the resolution of symptoms within 3 to 5 days of treatment. Coughing and fatigue may take up to 2 weeks or longer to improve, and chest x-rays can take up to a month (sometimes longer) to demonstrate an improvement in infiltrates, even in mild cases. Elements that can contribute to non-resolving pneumonia include pathogen type (TB or MDR organisms) and host factors (increased age, immunodeficiency, airway disease, cancer, AUD, or tobacco use), which can complicate the disease course (Gronthoud, 2020; Ost et al., 2023).

              If a patient has difficult-to-treat or non-resolving pneumonia, MDR organisms or atypical pathogens should be of priority concern. Recent travel should be re-evaluated with the patient and caregiver. Patients living in the Mississippi region are at risk for histoplasma, and patients residing in the remainder of the southern US are at risk for coccidioidomycosis. Rare pathogens may affect patients with cavitary lesions or allogeneic bone marrow transplants. Patients with HIV, immune deficiencies, asplenia, AUD, seizures, poor oral hygiene, a history of aspiration, and COPD have increased host-related factors for non-resolving pneumonia. They should be monitored for effusions, empyema, and lung abscesses. Pulmonary aspergillosis should be considered if the patient is immunocompromised (AIDS, severe neutropenia, or chronic corticosteroid use). Non-infectious causes of non-resolving pneumonia include pulmonary embolisms, malignancy, sarcoidosis, pulmonary vasculitis syndromes, eosinophilic pneumonia, and alveolar damage (Gronthoud, 2020; Ost et al., 2023).

              If a patient is slowly improving, they should be carefully monitored for 4 to 8 weeks, and referral to a pulmonologist for specialty evaluation is encouraged. A more aggressive diagnostic approach should be initiated if no resolution or improvement occurs or if the illness progresses. An extensive medical history and physical examination should be repeated. Antibiotics should be changed per recommendations, and the patient should be evaluated for possible signs of malignancy. A high-resolution chest CT scan should be obtained, and a CT pulmonary angiogram should be considered to rule out a pulmonary embolism. If the CT imaging demonstrates worsening infiltrates and symptoms are progressing, bronchoscopy or other forms of invasive testing should be considered, followed by further evaluation with a thoracoscopic or open lung biopsy. Neoplastic pulmonary lesions may cause a blocked airway (either directly or through compression), resulting in non-resolving pneumonia (Gronthoud, 2020; Ost et al., 2023).

Sepsis

Sepsis starts with an infection—most often pneumonia—that triggers a dysregulated host response. Pneumonia patients should be monitored closely for indications of sepsis, and SpO₂ should be evaluated with every vital sign assessment. Systemic inflammatory response syndrome criteria for sepsis include suspected or diagnosed infection with at least two of the following.

• temperature greater than 101° F (38.3° C) or less than 96.8° F (36° C)
• HR greater than 90/min
• RR greater than 20/min
• arterial hypotension (systolic blood pressure less than 90 mm Hg, mean arterial pressure [MAP] less than 70 mm Hg)
• arterial hypoxemia (PaO₂/FiO₂ less than 300)
• absent bowel sounds
• decreased capillary refill or presence of mottling
• unexplained change in mental status
• significant edema or positive fluid balance
• abnormal WBC count (greater than 12,000/mm³ or less than 4,000/mm³)
• normal WBC count with greater than 10% bands
• platelets less than 100,000/mm³
• international normalized ratio greater than 1.5 or activated partial thromboplastin time greater than 60 seconds
• plasma CRP greater than 2 standard deviations above normal
• elevated lactic acid (lactate) level (greater than 2.0 mmol/L)
• plasma procalcitonin greater than 2 standard deviations above normal
• urine output less than 0.5 mL/kg/hr for 2 hours despite adequate fluid resuscitation
• creatinine increase greater than 0.5 mg/dL
• elevated total bilirubin (greater than 4 mg/dL)
• hyperglycemia (plasma glucose greater than 140 mg/dL) in the absence of diabetes (Gauer et al., 2020)

The Third International Consensus for Sepsis and Septic Shock defines sepsis as "life-threatening organ dysfunction caused by a dysregulated host response to infection" (Singer et al., 2016, p. 1). They suggest assessing for organ dysfunction using the Sequential (sepsis-related) Organ Failure Assessment (SOFA) score (Marik & Taeb, 2017; Singer et al., 2016). SOFA is a simple scoring system that notes the number and severity of failure in six organ systems (the respiratory system, coagulative function, cardiovascular system, liver, kidneys, and neurological system). It was developed in 1994 to describe the degree of organ failure over time (Lambden et al., 2019). The score ranges from 0 to 24, and higher scores predict a higher possibility of mortality (Vafaei et al., 2019). The SOFA score should be calculated on admission (before initiating treatment) and then every 24 hours for daily monitoring of acute morbidity in ICU patients. Clinical guidelines define multiorgan dysfunction as acute changes in the SOFA score of 2 or more points due to the infection (CDC, 2018). While initially developed to measure morbidity and not outcomes, the developers acknowledge that measurements of morbidity are associated with predicting mortality (Lambden et al., 2019). Respiratory function is assessed using the ratio of partial pressure of oxygen in the arterial blood (PaO2) to the fraction of inspiratory oxygen (FiO2), or the P/F ratio. Hematologic dysfunction is assessed using the patient's platelet count. Liver function is assessed using bilirubin level (in mg/dL). Cardiovascular function is assessed using the patient's mean arterial pressure (MAP) with additional points added if catecholamines (dopamine) were required to maintain perfusion/pressure. The Glasgow coma scale is included as an assessment of neurological function, and creatinine included to represent renal function (Lambden et al., 2019; Marik & Taeb, 2017; Vincent et al., 1996). An increase of 2 or more points in the patient's SOFA score is generally considered to represent dysfunction (Marik & Taeb, 2017; Singer et al., 2016). For additional information regarding the risk factors, diagnosis, and management of sepsis, refer to the NursingCE course Overview of Sepsis.

 

Health Promotion and Prevention

For pneumonia prevention among pediatric patients, all vaccinations should be encouraged, especially for S. pneumoniae, H. influenzae type B, and pertussis. Yearly influenza vaccines are recommended, and parents and caretakers should be immunized against influenza and pertussis (Metlay et al., 2019). CAP prevention in adults can be accomplished via smoking cessation, annual influenza vaccination, and pneumococcal vaccination administration (Ramirez, 2024). Handwashing is a prevention technique that applies at home and in health care settings. Patients with respiratory symptoms should visit a health care provider for a fever lasting more than 24 hours, a respiratory or other systemic sickness that persists for more than a week, or worsening symptoms despite rest. Respiratory therapy equipment should be decontaminated and replaced as per manufacturer guidelines. Sterile water should be used instead of tap water for GI tubes. Patients must be screened for aspiration risk, and aspiration precautions should be initiated as indicated. Thorough assessments and the use of patient care bundles in the ICU environment can significantly reduce the risk for VAP. Patients who smoke and are diagnosed with pneumonia should also receive smoking cessation education (Ignatavicius & Workman, 2018).

 

Vaccination

              Vaccination for pneumococcal disease has been available since 1983, prompting a decline in CAP caused by pneumococcus in the US. While S. pneumoniae is the most common cause of CAP, the organism may also cause otitis media, meningitis, and bacteremia. The pneumococcal vaccines (PCVs) are divided into whole-cell and subunit types. Whole-cell vaccines consist of live attenuated and inactivated forms. Subunit types include polysaccharide, conjugate, and protein-based vaccines. Whole-cell live attenuated vaccines provide superior protection against various pneumococcal serotypes, while inactivated vaccines use pathogens that are treated with chemicals or physical processes to enhance safety (Micoli et al., 2023).

According to the CDC (2023c), there are two kinds of PCVs recommended in the US: pneumococcal polysaccharide vaccine (PPSV23) and pneumococcal conjugate vaccines (PCVs [PCV15 and PCV20]). A polysaccharide is comprised of long chains of sugar molecules that appear similarly to the surface of certain types of bacteria to help the immune system mount a response. A polysaccharide (subunit) vaccine uses the polysaccharide capsule from encapsulated bacteria. The polysaccharide interacts with B-cells and directly induces antibodies without a T-cell response. The PPSV includes polysaccharides from 23 serotypes of pneumococcal bacteria, responsible for 80% to 90% of pneumococcal infections worldwide. While PPSV23 (Pneumovax 23) vaccination does not prevent CAP, it does alleviate its severity. It is effective against invasive pneumococcal disease. The PPSV23 (Pneumovax 23) vaccine is usually given as a one-time dose in adults over the age of 65. However, some experts have suggested that older patients and those with chronic health problems might benefit from a second vaccination at least 5 years after their first dose (Micoli et al., 2023).

A conjugate is a type of vaccine that attaches a protein to an antigen to improve the amount of protection the vaccine delivers. A weakened form of the pathogen is used in a live attenuated vaccine. A conjugate (subunit) vaccine uses polysaccharide antigens conjugated with carrier proteins. Unlike the polysaccharide vaccine, the conjugate vaccine can elicit a T-cell response, creating superior immunogenicity and longer-lasting immunity. The pneumococcal conjugate vaccine with seven polysaccharides (PCV7) was commercially available as Prevnar. The pneumococcal conjugate vaccine with 10 polysaccharides (PCV10) is called Synflorix. Finally, the polysaccharide vaccine with 13 polysaccharides (PCV13) is known as Prevnar 13. Because of the different serotypes included in these vaccines, some work better for specific populations than others. PCV7 (Prevnar) has demonstrated protective effects against invasive pneumococcal disease, pneumonia, and otitis media. PCV7 (Prevnar) can also protect HIV-infected adults from pneumococcal infection. PCV13 (Prevnar 13) decreased the incidence of pneumococcal pneumonia in children because it contains the two serotypes that cause about half of childhood pneumococcal cases. Unfortunately, PCV13 (Prevnar 13) is more expensive than the PPSV23 (Pneumovax 23) vaccine. Currently, PCV15 (Vaxneuvance) and PCV20 (Prevnar 20) are available and recommended for use within the US (CDC, 2023b; Micoli et al., 2023).

Pneumococcal Vaccination in Children

The CDC (2023c) recommends the PCV15 (Vaxneuvance) or PCV20 (Prevnar 20) for all children younger than 5 years. Infants should routinely receive the PCV15 or PCV20 as a series of four doses, with one dose administered at each of the following ages: 2 months, 4 months, 6 months, and 12 through 15 months. Children younger than 5 years who missed their shots or started the series later than the ages outlined above should still be vaccinated. However, the number of doses recommended and the intervals between doses vary depending on the child's age when vaccination begins. The CDC (2023b) offers catch-up guidance for healthy children 4 months through 4 years who require PCV. Children must be at least 2 years old to receive the PPSV23 (Pneumovax23) vaccine (CDC, 2023b). Children with a cerebrospinal fluid (CSF) leak, diabetes, chronic heart, liver, kidney, or lung disease, or a cochlear implant with no history of PPSV23 (Pneumovax 23) or PCV20 should receive a dose of either PPSV23 or PCV20 at least 8 weeks after their most recent PCV vaccine. Those aged 6 to 18 may need a second dose 5 years later. Children with sickle cell disease, other hemoglobinopathies, asplenia, congenital or acquired immunodeficiency, HIV, chronic renal failure, nephrotic syndrome, malignant neoplasms, leukemias, lymphomas, Hodgkin's disease, immunosuppressive or radiation therapy, solid organ transplants, or multiple myeloma should receive a dose of PPSV23 (Pneumovax 23) or PCV20 at least 8 weeks after any previous PCV doses and then repeated 5 years later. A summary of PCV and PPSV23 (Pneumovax 23) vaccine recommendations for children appears in Table 8 (CDC, 2023b).

Table 8

 

PSV15 (Prevnar15) and PPSV23 (Pneumovax 23) Vaccine Recommendations for Children

 

Healthy Children	Children with CSF leak, chronic heart disease, chronic lung disease, diabetes, or cochlear implant	Children with sickle cell, hemoglobinopathies, asplenia, congenital or acquired immunodeficiency, HIV, chronic renal failure, nephrotic syndrome, malignant neoplasms, leukemias, lymphomas, Hodgkin's disease, immunosuppressive or radiation therapy, solid organ transplants, or multiple myeloma
PCV20 (Prevnar 20) or PVC15 (Vaxneuvance)
Ages 6 weeks to 2 years
Four doses given at: 2 months 4 months 6 months 12 to 15 months
Ages 2 to 5 years
A single dose if the series is not completed before age 2	If the patient previously received: three doses, need one more two or fewer, need two more	If the patient previously received: three doses, need one more two or fewer, need two more
Ages 6 to 18 years
No recommendations	If no prior PCV, need one dose	If no prior PCV, need one dose
PPSV23 (Pneumovax 23)
No recommendations	One dose after completing the PCV series	Two doses after completing the PCV series, 5 years apart

(CDC, 2023b)

Pneumococcal Vaccination in Adults

If a patient receives the PPSV23 (Pneumovax 23) vaccine before age 65, they should repeat the vaccine at least 5 years later when they are over age 65. For patients ages 19 to 64 years with cochlear implant, congenital or acquired asplenia, CSF leak, generalized malignancy, HIV infection, Hodgkin's disease, immunodeficiencies, iatrogenic immunosuppression, leukemia, lymphoma, multiple myeloma, nephrotic syndrome, solid organ transplant, sickle cell disease, chronic heart conditions, lung disease, liver disease, renal failure, diabetes, AUD, or a history of smoking, a single dose of PCV15 or PCV20 should be administered. If PCV15 (Vaxneuvance) is given, a single dose of PPSV23 (Pneumovax 23) should be given at least 1 year later. The use of PCV20 (Prevnar 20) negates the need for a follow-up dose of PPSV23. Those who have previously received PCV13 should be given a single dose of PCV20 or PPSV23 at least 1 year after their last dose of PCV13. Those who previously received a dose of PPSV23 may be given a single dose of either PCV15 or PCV20 1 year after PPSV23 administration. Those who received PCV13 and PPSV23 may receive a repeat dose of PPSV23 (Pneumovax 23) or PCV20 at least 5 years later (CDC, 2023a, 2023c).

The CDC recommends a dose of PPSV23 (Pneumovax 23) for all adults ages 65 years and older. Health care professionals should discuss the risks and benefits of getting the PCV20 (Prevnar 20) or PVC 15 (Vaxneuvance) vaccine with healthy adult patients 65 and older who have never received a conjugate vaccine or received only the PCV7. If a patient receives the PCV15 (Vaxneuvance), this should be given first, and the provider should administer the PPSV23 (Pneumovax 23) 1 year later (minimum of 8 weeks for immunocompromised adults or those with cochlear implant or CSF leak). The use of PCV20 (Prevnar 20) negates the need for a follow-up dose of PPSV23. Those who have previously received PCV13 should be given a single dose of PCV20 or PPSV23 at least 1 year after their last dose of PCV13. A single PCV20 (Prevnar 20) dose is recommended for adults over 65 with immunosuppression, a CSF leak, or a cochlear implant. For immunosuppressed patients aged 65 and over, a repeat dose of PPSV23 (Pneumovax 23) should be given at least 5 years later. Only a single dose of PPSV23 (Pneumovax 23) should be given to healthy patients 65 or older (CDC, 2023a, 2023c).

 

H. Influenzae Type B Vaccine (Hib)

The CDC (2021) recommends the Hib vaccine for infants at the following ages: 2 months, 4 months, and 6 months (depending on the brand), followed by a booster at 12 to 15 months. The Hib vaccine brand PedvaxHib is a two-dose series with the third booster given between 12 and 15 months. The Hib vaccine is also recommended for all children under 5 years. Older children and adults may not need a Hib vaccine. These vaccines are contraindicated in people who have experienced anaphylaxis or another severe reaction to a previous Hib dose, those who are allergic to any of the vaccine components, and those under the age of 6 weeks. For patients with moderate to severe acute illness with or without fever, the provider and the patient should weigh the risks and benefits of vaccination (CDC, 2021). Adults with asplenia or sickle cell disease should receive a Hib vaccine if they did not receive it as a child. If an elective splenectomy is performed, the patient should receive a dose at least 14 days before the scheduled procedure. Six to 12 months after hematopoietic stem cell transplant, a three-dose series should be given, regardless of the patient's Hib vaccination history (CDC, 2023a).

Influenza Vaccination

Pneumonia is a common coinfection with influenza, especially in the older adult population. Thus, the CDC (2023e) recommends routine annual influenza vaccination for all persons aged 6 months and older who do not have contraindications. Most people only need one dose of influenza vaccine each season. For these persons, the vaccination dose should ideally be offered during September or October but can continue throughout the season as long as the influenza virus is circulating (CDC, 2023e).

 

HAP/VAP Prevention Strategies

Implementing prevention measures for aspiration and oral bacterial translocation to the lower respiratory tract is critical to reduce the risk for HAP/VAP. Infection can be prevented through strict adherence to infection control, such as handwashing and aseptic technique during suctioning and caring for ETTs or tracheostomy tubes. Ventilator bundles are order sets designed to prevent VAP by preventing aspiration. These ventilator bundles usually include orders to:

• Keep the head of the bed elevated to at least 30°.
• Perform oral care per agency policy, usually brushing teeth every 8 hours and using an antimicrobial rinse such as chlorhexidine every 2 hours.
• Maintain pulmonary hygiene, which includes chest physiotherapy, postural drainage, and turning and positioning (Ignatavicius & Workman, 2018).

The most recent VAP prevention guidelines published by the Society for Healthcare Epidemiology of America and ATA/IDSA (Klompas et al., 2022) recommend avoiding intubation whenever possible via noninvasive ventilation methods, minimizing the transport of ventilated patients, using weaning protocols to extubate ventilated patients more efficiently, minimizing sedation (use sparingly, with daily sedation vacations in adults and spontaneous breathing trials without sedation in adults and pediatrics), maintaining the physical conditioning of critically ill and ventilated adults, minimizing pooling of secretions at the ETT cuff, elevating the head of the bed in adults and pediatrics, and maintaining ventilator circuits (changing circuits when visibly soiled or malfunctioning). In ventilated neonates, the recommended positioning to reduce VAP risk is the lateral recumbent or reverse Trendelenburg positions, and daily sedation vacations/spontaneous breathing trials are not recommended. Combining these prevention measures into a bundle may be a practical method of enhancing HAP/VAP prevention efforts, although the evidence regarding their effectiveness is mixed (Klompas et al., 2022).

ETTs that can drain subglottic secretions continuously or intermittently have been developed to avoid pooled secretions that may lead to aspiration. They are more expensive and not consistently available but are recommended if available in adults expected to require more than 48 hours of mechanical ventilation (Klompas, 2023b). ETTs with subglottic drainage ports are not recommended for use in ventilated neonates or younger pediatric patients. The use of ultrathin polyurethane ETT cuffs or automated control of ETT cuff pressure may decrease the VAP rate. Still, the available evidence is low-quality and insufficient to determine if this impacts the duration of mechanical ventilation, length of stay, or mortality. Similarly, saline instillation before tracheal suctioning may decrease the rate of VAP, but the low-quality evidence was insufficient to determine if this reduces the duration of mechanical ventilation or length of stay or improves mortality (Klompas et al., 2022).

Oral care is also a component of VAP prevention, although policies vary regarding timing, products, and application methods. VAP prevention efforts initially targeted the prevention of aspiration. However, many studies showed that oral care improvement contributed to VAP reduction significantly. Even though oral care may contribute to VAP prevention, a best-practice protocol has not yet been identified. Some oral care methods include toothbrushing or sponge swabs, and products consist of a chlorhexidine rinse or a sodium chloride solution. Most recommended oral care frequencies range from twice daily to every 2 hours (Ignatavicius & Workman, 2018). In neonates, the guidelines recommend regular oral care with sterile water. In pediatrics, regular oral care with a toothbrush or gauze is recommended over the use of chlorhexidine. Routine oral care with chlorhexidine in ventilated adults may decrease the rate of VAP. However, moderate-quality evidence was insufficient to determine if this impacts the duration of mechanical ventilation, length of stay, or mortality. Similar assessments were made by the recently updated 2022 guidelines regarding mechanical tooth brushing (Klompas et al., 2022).

Probiotics were previously thought to decrease the rate of VAP but are no longer recommended in the updated 2022 guidelines (Klompas et al., 2022). Selective oral or digestive decontamination with nonabsorbable antibiotics was reviewed, but the data on the associated risks (increase in antimicrobial resistance) and benefits were deemed insufficient. The 2022 pneumonia prevention guidelines recommend against silver-coated ETTs, kinetic beds, and prone positioning due to a lack of impact on the duration of mechanical ventilation, length of stay, or mortality. They also recommend against stress ulcer prophylaxis, early tracheotomy, monitoring residual gastric volumes, early parenteral nutrition, and closed/inline endotracheal suctioning in adults due to a lack of evidence that these reduce the VAP rate. Closed/inline suctioning may prevent VAP in neonates (Klompas et al., 2022).

 

Patient Education

              According to the CDC (2023d), handwashing is one of the most important actions people can take to avoid getting sick and reduce the transmission of illnesses to others. Research shows that proper handwashing with soap and water could protect about 1 in 5 young children with respiratory infections like pneumonia. Handwashing reduces the rate of respiratory infections by eradicating respiratory pathogens from the hands and preventing them from entering the body. Patients should receive education on their risk factors for pneumonia, especially those over 65 years old or those with comorbid chronic respiratory conditions or limited mobility. Available vaccinations, including the annual influenza and pneumococcal vaccines, should be encouraged. Patients should be educated on strategies to reduce the transmission of respiratory illnesses, such as avoiding contact with sick people and crowded places during flu and holiday seasons. They should also be taught how to cough, turn, and breathe deeply, especially in the context of mobility problems. Incentive spirometry should be provided when available. If a patient uses at-home respiratory equipment, proper disinfecting and storage methods should be clearly communicated and demonstrated. Patients should also receive education and support for smoking cessation and be counseled to avoid indoor pollutants like dust, smoke (firsthand or secondhand), and chemicals such as aerosol sprays. Proper nutrition and fluid intake are also crucial aspects of patient teaching (Ignatavicius & Workman, 2018).

              Prior to discharge from hospitalization for pneumonia, patients and caregivers must receive adequate education on proper discharge instructions and a follow-up plan. All prescribed medications should be reviewed with the patient or caregiver. Clinicians should emphasize the importance of completing the entire course of antibiotics or antifungals as prescribed. Patients and caregivers must also receive education on when to notify their health care provider, such as if they experience fevers, chills, persistent or worsening cough, dyspnea, hemoptysis, increased sputum production, wheezing, chest discomfort, or progressive fatigue. Patients recovering from pneumonia should be instructed to rest, stay hydrated, and increase activity gradually as tolerated (Ignatavicius & Workman, 2018).

 

Case Study

The nurse is caring for Mrs. Mitchell, a frail 82-year-old woman. Mrs. Mitchell was admitted to the hospital from an assisted living facility for surgery to repair a bowel obstruction. Her surgery concluded 49 hours ago. She currently has an NG tube set to low suction. All of her medications are administered through the NG tube, including warfarin (Coumadin), cimetidine (Tagamet), and lisinopril (Zestril). Mrs. Mitchell receives oxygen at 1 liter per minute via nasal cannula at home while sleeping. She currently has an indwelling urinary catheter and a saline-locked peripheral IV in the right forearm that was placed 72 hours ago. She reports increased weakness, fatigue, and chest pain unrelieved by IV opioids and refuses physical therapy participation. Most of her time each day has been spent in bed. Her most recent vital signs are as follows: BP 100/72 mm Hg, heart rate 98/min, oral temperature 100.5° F (38.1° C), respiratory rate 24/min, and SpO₂ 91%. Her most recent lab results include WBC 6,000/mm³, BUN/creatinine 29/1.4, sodium 146 mEq/L, and lactic acid 5 mmol/L. Upon pulmonary assessment, the nurse auscultates diminished breath sounds and dull percussion over the right upper lobe. Mrs. Mitchell has no accessory muscle use and denies dyspnea.

What risk factors does Mrs. Mitchell have for developing pneumonia?

Mrs. Mitchell's advanced age, residence in an assisted living facility, recent surgery, NG tube placement, use of an H2 blocker (Tagamet), use of home respiratory equipment, and decreased mobility are all risk factors for pneumonia.

What physical findings, vital signs, and laboratory results suggest possible pneumonia?

Physical assessment findings consistent with pneumonia include decreased breath sounds and dull percussion. Mrs. Mitchell’s BP is on the lower end of normal and should be compared to her baseline. Her respiratory rate is high, and her SpO₂ is low. She has a mild temperature elevation; however, 49 hours after surgery, this could be due to the inflammatory process. Mrs. Mitchell’s WBC is normal, but this often occurs in older adults with pneumonia. Her BUN/creatinine and sodium levels are all slightly elevated. These findings suggest possible dehydration. Subjectively, the patient reports chest pain, increased weakness, and fatigue.

With which classification of pneumonia would Mrs. Mitchell most likely be diagnosed?

Mrs. Mitchell lives in an assisted living facility, which puts her at increased risk for MDR pathogens (see Table 6). She has developed symptoms over 48 hours after admission for an invasive abdominal procedure, so she would most likely be diagnosed with HAP.

One day later, Mrs. Mitchell's NG tube is removed. Her diet is advanced to ice chips and clear liquids. The nurse notices that when Mrs. Mitchell drinks liquids, she repeatedly swallows and coughs. What is the medical team most concerned about currently? What action should they take?

Mrs. Mitchell's coughing and frequent swallowing with thin liquids suggest aspiration. She should receive a referral for a swallow function study with a speech and language pathologist. Thin liquids should be withheld until the study can be performed.

Another day passes, and Mrs. Mitchell becomes more fatigued. Her family is concerned that she is not acting like herself. A chest x-ray is obtained, but the results are inconclusive for pneumonia. What should be done at this time?

Chest x-ray findings for older adults may be inconclusive for pneumonia, especially early in the process. Sputum and blood cultures should be considered, and a CBC and lactic acid should be repeated. Broad-spectrum antibiotics should be initiated after sputum and blood cultures are collected until culture sensitivities are available.

Mrs. Mitchell begins IV levofloxacin (Levaquin) and shows an improvement in symptoms within 24 hours. She is being prepared for discharge back to her long-term care facility. She is no longer tachypneic, and her SpO₂ is consistently 94% or higher. The patient reports feeling slightly better. What should be done in preparation for discharge?

Her dosage of IV antibiotics should be changed to an equivalent oral dosage in preparation for discharge to ensure she receives a total duration of 7 days of antimicrobial therapy. If Mrs. Mitchell tolerates the change and her condition continues to improve, she can be discharged home safely on the oral regimen.

When should Mrs. Mitchell be instructed to follow up for a repeat chest x-ray?

If Mrs. Mitchell's symptoms continue to improve after discharge and she completes the 7 days of treatment, a follow-up chest x-ray is not recommended. Further chest x-rays may not show improvement for a month or longer, even for mild pneumonia. While Mrs. Mitchell does not need a follow-up chest x-ray, she should still be scheduled for a follow-up evaluation with her primary care provider after completing the antibiotic course.

References

American Thoracic Society. (2019). Top 20 pneumonia facts-2019. https://www.thoracic.org/patients/patient-resources/resources/top-pneumonia-facts.pdf

Boruchoff, S. E. & Weinstein, M. P. (2024). Sputum cultures for the evaluation of bacterial pneumonia. UpToDate. Retrieved March 3, 2024, from www.uptodate.com/contents/sputum-cultures-for-the-evaluation-of-bacterial-pneumonia

Bradley, J. S., Byington, C. L., Shah, S. S., Alverson, B., Carter, E. R., Harrison, C., Kaplan, S. L., Mace, S. E., McCracken, G. H., Jr, Moore, M. R., St Peter, S. D., Stockwell, J. A., & Swanson, J. T. (2011). The management of community-acquired pneumonia in infants and children older than 3 months of age: Clinical practice guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America. Clinical Infectious Diseases, 53(7), e25–e76. https://doi.org/10.1093/cid/cir531

British Thoracic Society. (2016). Adult community-acquired pneumonia: CAP care bundle. https://www.brit-thoracic.org.uk/document-library/quality-improvement/adult-cap/cap-care-bundle/

Centers for Disease Control and Prevention. (2018). Hospital toolkit for adult sepsis surveillance. https://www.cdc.gov/sepsis/pdfs/Sepsis-Surveillance-Toolkit-Aug-2018_508.pdf

Centers for Disease Control and Prevention. (2021). Haemophilus influenzae disease vaccination. https://www.cdc.gov/vaccines/vpd/hib/index.html

Centers for Disease Control and Prevention. (2022). Haemophilus influenzae disease (including Hib). https://www.cdc.gov/hi-disease/index.html

Centers for Disease Control and Prevention. (2023a). Immunization schedules: Adult immunization schedule. https://www.cdc.gov/vaccines/schedules/hcp/imz/adult-index.html

Centers for Disease Control and Prevention. (2023b). Immunization schedules: Child and adolescent immunization schedule. https://www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html

Centers for Disease Control and Prevention. (2023c). Pneumococcal vaccine recommendations. https://www.cdc.gov/vaccines/vpd/pneumo/hcp/recommendations.html#routine-vaccination

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