Community-Acquired Pneumonia

Infectious Diseases

Acute lower respiratory infection with consolidation on imaging, acquired outside hospital.

Causes

  • S. pneumoniae (most common)
  • H. influenzae
  • Mycoplasma, Chlamydia, Legionella
  • Influenza, RSV, SARS-CoV-2

Clinical features

  • Fever, productive cough
  • Pleuritic chest pain
  • Dyspnoea

Examination

  • Tachypnoea, dull percussion
  • Bronchial breathing, crackles
  • Increased vocal resonance

Investigations

  • CXR (consolidation)
  • FBC, U&E, CRP
  • Sputum + blood cultures if severe
  • Pneumococcal + Legionella urinary antigen
  • Viral PCR

Diagnosis

  • CURB-65 0–1 outpatient, 2 ward, ≥3 ICU consideration

Management

  • Mild: amoxicillin 500 mg–1 g TDS PO
  • Moderate: amoxicillin + clarithromycin
  • Severe: co-amoxiclav + clarithromycin IV
  • 5–7 days typically

Complications

  • Para-pneumonic effusion / empyema
  • Sepsis, ARDS
  • Lung abscess

Clinical pearls

  • Atypical cover (macrolide) for moderate–severe CAP
  • Re-image at 6 weeks if persistent symptoms

References

  • NICE NG138
  • BTS CAP 2009

Educational — verify locally.

WardRound

WardRound

Clinical Decisions in Seconds