Bedside Rounds

Community-acquired pneumonia: workup and management

Community-acquired pneumonia: acute respiratory symptoms with a new infiltrate. Use CURB-65 or PSI with clinical judgement to choose site of care, and ATS/IDSA criteria to identify severe CAP.

Working diagnosis Adult · US guidelines Draft · awaiting physician review
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01Orient

What's new in the evidence

  • SCCM 2024 focused update: strong recommendation for corticosteroids in hospitalized adults with severe bacterial CAP (no benefit in less severe CAP)
  • CAPE COD (2023): hydrocortisone 200 mg/day for 4–7 days then tapered reduced 28-day mortality in severe CAP
  • PTC (2021): stopping beta-lactam after 3 days in stable, improving ward patients was noninferior to 8 days
  • MRSA nasal PCR has a high negative predictive value for stopping empiric anti-MRSA therapy

Differential diagnoses

  1. Bacterial CAP (S. pneumoniae, H. influenzae, atypicals)
  2. Viral pneumonia (influenza, COVID-19, RSV)
  3. Aspiration pneumonia
  4. Pulmonary embolism with infarction
  5. Heart failure
  6. Lung cancer with post-obstructive pneumonia
  7. Tuberculosis
  8. Organizing pneumonia, eosinophilic pneumonia

02Assess

Risk scores and decision tools

  • CURB-65 or PSI for site of care
  • ATS/IDSA severe CAP criteria (1 major or ≥3 minor)
  • Clinical stability criteria (temperature, HR, RR, SBP, SpO₂, mental status, oral intake) to stop antibiotics or switch to oral

Key history questions

  • Cough, sputum, fever, pleuritic pain, dyspnea duration
  • Recent hospitalization or IV antibiotics (MRSA/Pseudomonas risk)
  • Prior MRSA or Pseudomonas in respiratory cultures
  • Swallowing problems, alcohol, reduced consciousness (aspiration)
  • TB exposure, travel, immunosuppression
  • Smoking and weight loss

Examination findings

  • RR, SpO2, BP, confusion
  • Focal crackles, bronchial breathing, dullness
  • Signs of effusion

03Investigate

Initial investigations

  • Chest X-ray
  • CBC, BMP (urea for CURB-65)
  • SpO2; blood gas if hypoxic
  • Influenza and SARS-CoV-2 testing in season

Advanced investigations

  • Blood and sputum cultures for severe CAP or MRSA/Pseudomonas risk
  • Legionella and pneumococcal urinary antigen in severe CAP
  • MRSA nasal PCR (high negative predictive value to stop vancomycin)
  • CT chest if X-ray unclear; ultrasound for effusion

04Treat

Immediate management

  • Oxygen to target SpO2
  • Antibiotics promptly; sepsis pathway if organ dysfunction

First-line treatment

  • Outpatient, no comorbidity: amoxicillin 1 g three times daily, or doxycycline 100 mg twice daily
  • Outpatient with comorbidity: amoxicillin-clavulanate plus macrolide or doxycycline, or respiratory fluoroquinolone
  • Inpatient non-severe: ceftriaxone 1-2 g IV daily plus azithromycin 500 mg daily
  • Minimum 5 days, stopping once clinically stable for 48 h

Second-line treatment

  • Severe CAP meeting CAPE COD criteria (ventilation, high-flow O₂ with P/F <300 and FiO₂ ≥50%, or PSI >130): hydrocortisone 200 mg/day for 4–7 days then taper over 8 or 14 days total; not studied in influenza or aspiration
  • Add vancomycin or linezolid if MRSA risk; piperacillin-tazobactam or cefepime if Pseudomonas risk
  • Drain complicated parapneumonic effusion or empyema

Specialist referrals

  • ICU for severe CAP (vasopressors or mechanical ventilation, or 3+ minor criteria)
  • Pulmonology for non-resolving pneumonia

05Disposition

Admission criteria

  • CURB-65 of 2 or more, or PSI class IV-V
  • Hypoxia (SpO2 under 92%)
  • Unable to take oral therapy or unsafe at home

Safe discharge criteria

  • CURB-65 0-1 with normal oxygenation
  • Tolerating oral intake and medication
  • Clinically stable: afebrile, HR under 100, RR under 24, SBP ≥90

Follow-up timing

  • Clinical review at 48-72 h if outpatient
  • Follow-up chest imaging at 6-8 weeks only if symptoms persist or malignancy risk

Patient instructions

  • Fatigue and cough can last weeks
  • Return if breathless, confused or not improving at 72 h

Monitoring

  • Daily clinical stability criteria for IV-to-oral switch

Clinical pearls and pitfalls

  • Pneumococcal and influenza vaccination at discharge
  • Fluoroquinolones carry tendon, aortic and QT risks

RefGuidelines and landmark evidence

For education only. Typical adult starting points; confirm doses against renal function, allergies, interactions and your institution's protocols. Not a substitute for clinical judgment or senior review.

Calculators for this workup

CURB-65
Acetaminophen overdoseAcute abdominal painAcute aortic dissectionAcute cholangitis and choledocholithiasisAcute decompensated heart failureAcute diverticulitisAcute dizziness and vertigoAcute ischemic stroke and TIAAcute kidney injuryAcute pancreatitisAcute pericarditisAdrenal crisisAlcohol withdrawalAlcohol-associated hepatitisAnaphylaxisAnemia in hospitalized adultsAsthma exacerbationAtrial fibrillation with rapid ventricular responseBacterial meningitisCellulitisChest painClostridioides difficile infectionCOPD exacerbationDecompensated cirrhosis (ascites, SBP, hepatic encephalopathy)Deep vein thrombosisDelirium / acute confusionDiabetic foot infection and osteomyelitisDiabetic ketoacidosisFebrile neutropeniaFirst seizure and status epilepticusHypercalcemiaHyperglycemia in hospitalized adultsHyperkalemiaHypernatremiaHyperosmolar hyperglycemic state (HHS)Hypertensive emergencyHypoglycemiaHypokalemiaHyponatremiaInfective endocarditisLower GI bleedMajor bleeding on anticoagulants (reversal)Malignant spinal cord compressionNSTEMI and non-ST-elevation ACSOpioid overdose and opioid use disorderPulmonary embolismPyelonephritis and complicated UTIRhabdomyolysisSepsisShortness of breathSickle cell vaso-occlusive crisisStaphylococcus aureus bacteremiaSymptomatic bradycardia and heart blockSyncopeThrombocytopenia (including TTP, HIT and ITP)Thunderclap headache (rule out subarachnoid hemorrhage)Thyroid stormTumor lysis syndromeUpper GI bleed