Community-acquired pneumonia (CAP) in adults

SITE OF CARE


• 90% of patients with CAP are treated as outpatients.


• Severity of illness drives all other treatment decisions.


• Severity-of-illness scores will both predict increased mortality risk for patients with high scores and avoid unnecessary hospitalization for patients with low scores. 


• Scoring systems are generally used to determine need for hospitalization: 


– CURB-65: Evaluate the patient for confusion, uremia, respiratory rate (>30 breaths/min), BP (90/60 mm Hg or lower), and age older than 65 years. Criteria totals drive treatment setting.


• 0-1: outpatient treatment 

• 2: hospitalize on general medical floor

• 3-5: ICU admission


– Pneumonia Severity Index: Class system based on


• Demographic factors (age, gender, nursing-home resident)

• Comorbid conditions (heart failure, neoplastic disease, cerebrovascular disease, renal disease, liver disease) 

• Physical examination findings (altered mental state, tachycardia, tachypnea, hypotension, fever) 

• Diagnostic test findings (acidotic state, hyperglycemia, hyponatremia, anemia, 
elevated BUN, low Po₂, 
pleural effusion)


– Class I patients (lowest risk) are typically younger than 50 years, with no coexisting conditions or abnormalities listed above.


– Classes II to V are determined by tabulating points assigned to each risk factor (see "Scoring system for prediction model" and "Stratification of risk score for prediction model" at www.ahrq.gov/clinic/pneuclin.htm). 


• Class II (<1% of cases) can 
be safely treated as an 
outpatient 

• Class III (1%-4% of cases) re­quires brief inpatient observation

• Class IV (4%-10% of cases) 
and class V (>10% of cases) need hospitalization.


TREATMENT


• Antibiotics should be started as soon as possible after diagnosis; delays of >8 hours increase mortality. 


• Empiric regimens adequately treat infections caused by most of the CAP pathogens.


• Use prevalence of drug resistance in the community as a guide, particularly for S pneumoniae strains. 


• Outpatient treatment


– Patients with no medical conditions and no risk for drug resistance: a macrolide or, if allergic, doxycycline 


– Patients with comorbidities, antibiotic treatment in the past 3 months, or risk for drug resistance: respiratory fluoroquinolone or, if allergic, beta-lactam plus a macrolide


• Inpatient treatment (non-ICU)


– Respiratory fluoroquinolone or beta-lactam plus a macrolide


• ICU treatment


– Monotherapy is not acceptable. 


– Beta-lactam plus either azithromycin or a fluoroquinolone


• Subjective response should be seen in 1 to 3 days with defervescence and improvement in respiratory symptoms and oxygen saturation. 


• If treated with IV antibiotics, switch to oral therapy as soon as fever subsides (usually after 3 days). 


– Oral administration of the same drug as IV therapy or one closely related is preferred 


• Antibiotics should be continued 
for 5 days or more and for a minimum of 72 hours after the patient is afe­brile. 


• Treatment for 14 days is indicated for infections caused by Legionella species, M pneumoniae, C pneumoniae.


PREVENTION AND PATIENT EDUCATION


• Patients who smoke should be counseled on the risks of pneumonia and offered appropriate smoking cessation strategies. 


• All persons 65 years or older should receive the pneumococcal vaccine.


• All persons 50 years or older should be vaccinated annually against influenza. JAAPA


Bill Kohlhepp is Associate Professor of Physician Assistant Studies, Quinnipiac University, Hamden, Connecticut, and a physician assistant at Saint Raphael's Occupational Health Plus in Hamden. The author has indicated no relationships to disclose relating to the content of this article.