Diagnosis and treatment of atypical pneumonia in critically-ill patients

'Atypical' pneumonia can be defined as pneumonia that is caused by bacteria lacking a typical cell wall, and those resistant to β-lactam and cephalosporin antibiotics. Therefore, 'atypical' pneumonia caused by Mycoplasma pneumoniae, Chlamydia pneumoniae, Chlamydia psittaci, Chlamydia trachomatis, Coxiella burnetti, and Legionellae are discussed. 'Atypical' pneumonia cannot be reliably distinguished from 'typical' pneumonia on clinically grounds, and simple tests are not usually helpful in the case of 'atypical' pneumonia. In severely ill patients with community-acquired pneumonia an agent with activity against the causes of 'atypical' pneumonia should always be included in the empiric antibiotic regimen. At present a macrolide antibiotic such as erythromycin is a reasonable choice. Rapid diagnostic tests are expensive, not widely available, and not yet shown to affect outcome. Antibiotic therapy may be rationalized or adjusted once a specific aetiological agents is identified. The best therapy for each cause of 'atypical' pneumonia is discussed. The newer fluoroquinolones may play an increasing role in treatment in the future, but clinical data in critically ill patients is awaited.

Duke Scholars

Author John Andrew Crump Medicine, Infectious Diseases