Community-acquired pneumonia in adults

Community-acquired pneumonia (CAP) is typically characterized by a new lung infiltrate on chest x-ray, together with one or more of the following: fever, chills, cough, sputum production, dyspnea, myalgia, arthralgia, pleuritic pain.

Order a chest x-ray in all patients with suspected CAP who are admitted to hospital to confirm or exclude diagnosis.

Order sputum and blood cultures in all hospitalized patients treated empirically for methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa, as well as in patients with severe CAP.

Use a validated clinical prediction rule for prognosis (e.g., Pneumonia Severity Index), along with clinical judgment, to determine whether the patient should be treated as an inpatient or outpatient.

Treat with empiric antibiotics. Broader-spectrum regimens are required in patients with comorbidities. Add antibiotic cover for MRSA and P aeruginosa if locally validated risk factors for either pathogen are present.

CAP is defined as pneumonia acquired outside of hospital or healthcare facilities. Clinical diagnosis is based on a group of signs and symptoms related to lower respiratory tract infection with presence of fever >100ºF (>38ºC), cough, expectoration, chest pain, dyspnea, and signs of invasion of the alveolar space. However, older patients in particular are often afebrile and may present with confusion and worsening of underlying diseases. This topic focuses on the diagnosis and management of CAP in immunocompetent adults; it does not cover pneumonia due to COVID-19 or in children. See Coronavirus disease 2019 (COVID-19) and Community-acquired pneumonia in children.