Investigations

Chest radiology is highly variable. The most frequent pattern is one of bronchial thickening with areas of interstitial infiltration and subsegmental atelectasis involving one of the lower lobes; sometimes, there may be dramatic shadowing in both lower lobes. Often there is no correlation between radiologic appearance and the clinical state of the patient.

White cell count is usually normal but ESR may be raised and C reactive proteins may be elevated.

Diagnosis is confirmed by: (1)

• a rise of specific antibody titre - occurs in most instances, but, obviously, requires paired samples separated by a week or more, and is therefore not useful in the initial diagnosis
• cold haemagglutination serology - present in about 50% of cases but may produce false positives in measles, infectious mononucleosis, adenovirus pneumonias, certain tropical diseases and collagen vascular disease
• isolation of Mycoplasma pneumoniae

1. British Thoracic Society. BTS guidelines for the management of community acquired pneumonia in adults: update 2009. Jan 2015