[Pulmonary infection in patients with lung cancer]

To determine the frequency of pneumonia in patients with primary lung cancer requiring hospital admission, the etiologic diagnosis, probable production mechanisms, and the factors which may condition the evolution.

A prospective study was carried out in patients with primary lung cancer requiring hospital admission between 1986-1990. The diagnosis of pneumonia was performed by clinical and radiologic criteria and the etiology, in all cases, by hemocultures, pulmonary aspiration puncture, transtracheal aspiration and bronchoscopic techniques.

The frequency of pneumonia was 12%. Etiologic diagnosis of the pulmonary infection was achieved in 16 patients and the most frequent etiologic agents were Gram negative (56%), anaerobic (31%) and Pneumocystis carinii (31%). Mortality was 16%. Community or nosocomial infection was not related with the evolution of the lung infection. Neither did diagnosis of the etiologic agent condition mortality attributable to the pneumonia but facilitated treatment.

Pulmonary infection is a frequent and severe disease in patients with primary lung cancer. Bronchial obstruction may be the related pathogenic mechanism in the greatest number of cases with pneumonia. Due to the etiologic spectrum of these infections the practice of reliable diagnostic techniques is recommended to obtain etiologic diagnosis in addition to the administration of initial wide spectrum empiric antibiotherapy against the mentioned germs.