Non-infectious mimics of community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common cause of presentation to healthcare facilities. The diagnosis of CAP is usually made in patients with suggestive symptoms, signs, and radiological features. A number of non-infectious conditions, including neoplastic lesions, pulmonary oedema, pulmonary embolism, drug-induced pneumonitis, diffuse alveolar haemorrhage syndromes, cryptogenic organising pneumonia and acute eosinophilic pneumonia, may present in a similar way and mimic CAP. These other conditions are often only thought of after patients that are being treated as CAP fail to respond to therapy. The non-infectious mimics of CAP require early diagnosis and appropriate treatment to decrease patient morbidity and mortality. This article is intended to create an awareness of the non-infectious mimics of CAP and highlight some of the more frequent conditions as well as those that require early diagnosis and treatment to prevent a poor outcome.