Comparative clinical and laboratory features of legionella with pneumococcal and mycoplasma pneumonias.

The clinical and laboratory features of 83 cases of community-acquired pneumococcal pneumonia (PP), 79 cases of legionella pneumonia (LP) and 62 cases of mycoplasma pneumonia (MP) have been compared. No unique features have been found in any group. Patients with MP were younger, were more likely to have had prior antibiotics before hospital referral, had a predominance of upper respiratory tract symptoms, low total white cell counts and lacked features of multisystem involvement. Multisystem features were common in both PP and LP with confusion, high fever, hyponatraemia, hypoalbuminaemia and abnormalities of liver function occurring more often in LP. A high leucocyte count was especially common in PP. Antibiotic therapy in community-acquired pneumonia must remain empirical until a definite microbiological diagnosis is made.