Pathophysiology
Clinical meaning
Outpatient management of CAP is appropriate for low-risk patients identified by CRB-65 score of 0 (no confusion, RR < 30, BP systolic >= 90 and diastolic > 60, age < 65) or PSI class I-II. The clinician must confirm adequate oxygenation (SpO2 >= 94%), oral medication tolerance, reliable follow-up, and social supports. Clinical reassessment at 48-72 hours (in-person or telephone) evaluates antibiotic response: fever should resolve within 72 hours, cough improvement within 5-7 days. Failure to improve by 72 hours requires diagnostic re-evaluation (repeat CXR, blood cultures, atypical pathogen testing) and consideration of hospitalization. Return-to-work guidance generally allows return when afebrile 24 hours and symptoms are improving. Complete symptomatic recovery typically takes 4-6 weeks for healthy adults.