chest xray in community acquired pneumonia (CAP)

Last edited 03/2019 and last reviewed 11/2020

When should a chest radiograph be performed in the community?

  • not necessary to perform a chest radiograph in patients with suspected community acquired pneumonia (CAP) unless (1,2):
    • the diagnosis is in doubt and a chest radiograph will help in a differential diagnosis and management of the acute illness
    • progress following treatment for suspected CAP is not satisfactory at review
    • the patient is considered at risk of underlying lung pathology such as lung cancer

  • when should the chest radiograph, if previously undertaken, be repeated during recovery?
    • the chest radiograph need not be repeated prior to hospital discharge in those who have made a satisfactory clinical recovery from CAP
    • guidance suggests that a chest radiograph should be arranged after about 6 weeks for all those patients who have persistence of symptoms or physical signs or who are at higher risk of underlying malignancy (especially smokers and those aged >50 years) whether or not they have been admitted to hospital (1,2)
      • note though that some expert opinion suggests (3):
        • in some series up to 10% of pneumonia has an underlying lung cancer
          • therefore all consolidation on CXR should be followed to resolution
          • it takes 6 weeks for radiological clearance of pneumonia on CXR (longer with COPD)
          • If not cleared at 6 weeks then refer as two week wait (TWW) with persistent consolidation
    • further investigations which may include bronchoscopy should be considered in patients with persisting signs, symptoms and radiological abnormalities at around 6 weeks after completing treatment (1,2)
    • it is the responsibility of the hospital team to arrange the follow-up plan with the patient and the general practitioner for those patients admitted to hospital (1,2)

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