EM · Community-acquired pneumonia
Community-acquired pneumonia
Also known as CAP · Pneumonia · Lobar pneumonia
Community-acquired pneumonia — CURB-65 with NICE site-of-care judgement (consider home at 0 or 1, hospital at 2 or more, intensive-care assessment at 3 or more), ATS/IDSA 2019 empiric regimens by severity, the septic-shock hour-1 antimicrobial clock, parapneumonic effusion drainage, and Legionella and aspiration caveats. ACEM-primary, globally tagged.
Checked against its sources on 4 Sept 2026
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Red flags
- A CURB-65 of 3 or more prompts intensive-care assessment; septic shock needs effective antimicrobials within the first hour of hypotension
- Never delay the first antibiotic for cultures; routine blood cultures are not required in non-severe CAP
- A rising urea with pneumonia is a sign of sepsis severity, not a primary renal problem — it is one of the CURB-65 criteria for this reason
- Legionella pneumonia presents with hyponatraemia, gastrointestinal symptoms, neurological features and deranged liver function tests — cover it with a macrolide and notify public health
- A parapneumonic effusion that is loculated or purulent is an empyema and needs a chest drain, not just antibiotics
Meet the patient
A 68-year-old smoker with diabetes arrives with three days of fever, rusty sputum, right-sided pleuritic pain, and worsening breathlessness. He is alert, respiratory rate 26, blood pressure 124 over 72, oxygen saturations 93 per cent on room air, and his urea is 8.4. The chest X-ray shows right lower-lobe consolidation. Urea above 7 mmol/L and age 65 or older give him CURB-65 of 2; NICE considers hospital-based care at score 2 or more, not automatic intensive care.[4][15]
The two questions that decide every CAP are two bedside answers in a minute: how sick is he? (CURB-65) and which drug, how fast? (the antibiotic ladder). Hold those two questions and everything below slots into place.[4][8]
References16ShowHide
- [1]Lim WS, Baudouin SV, George RC, et al. BTS guidelines for the management of community acquired pneumonia in adults: update 2009. Thorax, 2009.PMID 19783532
- [2]Lim WS. British Thoracic Society community acquired pneumonia guideline and the NICE pneumonia guideline: how they fit together. Thorax, 2015.PMID 25977290
- [3]Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia. An official clinical practice guideline of the American Thoracic Society and Infectious Diseases Society of America. Am J Respir Crit Care Med, 2019.PMID 31573350
- [4]Lim WS, van der Eerden MM, Laing R, et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax, 2003.PMID 12728155
- [5]Fine MJ, Auble TE, Yealy DM, et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med, 1997.PMID 8995086
- [6]Charles PG, Wolfe R, Whitby M, et al. SMART-COP: a tool for predicting the need for intensive respiratory or vasopressor support in community-acquired pneumonia. Clin Infect Dis, 2008.PMID 18558884
- [7]Evans L, Rhodes A, Alhazzani W, et al. Executive summary: Surviving Sepsis Campaign: International Guidelines for the Management of Sepsis and Septic Shock 2021. Crit Care Med, 2021.PMID 34643578
- [8]Kumar A, Roberts D, Wood KE, et al. Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med, 2006.PMID 16625125
- [9]Meehan TP, Fine MJ, Krumholz HM, et al. Quality of care, process, and outcomes in elderly patients with pneumonia. JAMA, 1997.PMID 9403422
- [10]Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis, 2007.PMID 17278083
- [11]Davies HE, Davies RJ, Davies CW, et al. Management of pleural infection in adults: British Thoracic Society Pleural Disease Guideline 2010. Thorax, 2010.PMID 20696693
- [12]Seymour CW, Gesten F, Prescott HC, et al. Time to treatment and mortality during mandated emergency care for sepsis. N Engl J Med, 2017.PMID 28528569
- [13]Barbash IJ, Davis BS, Yabes JG, et al. Treatment patterns and clinical outcomes after the introduction of the Medicare sepsis performance measure (SEP-1). Ann Intern Med, 2021.PMID 33872042
- [14]Rahman NM, Maskell NA, West A, et al. Intrapleural use of tissue plasminogen activator and DNase in pleural infection. N Engl J Med, 2011.PMID 21830966
- [15]National Institute for Health and Care Excellence Pneumonia in adults: diagnosis and management (CG191) NICE, 2014.Source
- [16]Porcel JM. [Parapneumonic pleural effusions and empyema in adults:current practice]. Rev Clin Esp, 2009.PMID 19889319