Percutaneous transthoracic needle aspiration of the lung. Diagnosing Pneumocystis carinii pneumonitis.

Percutaneous transthoracic needle aspiration was performed on 228 occasions to obtain lung specimens from 202 patients with suspected Pneumocystis carinii pneumonitis. In 121 patients the diagnosis was established by identifying P carinii organisms in lung aspirates. Six patients whose aspirates did not contain P carinii were found to have the organism at autopsy. Findings from toluidine blue O and Gomori methenamine silver nitrate stains were equally satisfactory for detecting P carinii, but the percentage of specific diagnosis was higher when specimens were stained with both. Pneumothorax that required a thoracotomy tube occurred in 39 patients. Other infectious agents, either bacteria or fungi, were found in only four patients. Percutaneous pulmonary needle aspiration--when performed under fluoroscopic guidance--is a rapid and effective method for the diagnosis of P carinii pneumonitis.