Community-Acquired Pneumonia (CAP)

CAP is one of the most common infectious causes of hospitalization and death worldwide. The 2019 ATS/IDSA guidelines provide evidence-based recommendations for diagnosis, severity assessment, and antimicrobial therapy.

• 1Severity assessment: PSI/PORT score or CURB-65 (confusion, urea >7, RR ≥30, BP <90/60, age ≥65)
• 2CURB-65: 0–1 = outpatient; 2 = consider hospitalization; 3–5 = hospitalize (ICU if ≥4)
• 3Outpatient: amoxicillin ± doxycycline or azithromycin (low comorbidity); respiratory FQ or β-lactam + macrolide (comorbidities)
• 4Inpatient non-ICU: β-lactam + macrolide OR respiratory fluoroquinolone
• 5ICU CAP: β-lactam + azithromycin OR β-lactam + respiratory FQ
• 6Steroids: hydrocortisone for severe CAP (CAPE COD trial: reduced 28-day mortality)

• Legionella: urine antigen test (detects serogroup 1 only); treat with FQ or azithromycin
• Pneumococcal urine antigen: useful for severe CAP; positive in ~50% of bacteremic pneumococcal CAP
• MRSA CAP: post-influenza, cavitary, hemoptysis, leukopenia — add vancomycin or linezolid
• Aspiration pneumonia vs aspiration pneumonitis: pneumonitis is chemical, self-limited; antibiotics only if infection suspected