[Pneumocystis carinii infections]

In children, Pneumocystis carinii pneumonias occur mainly in cases of congenital or acquired immunodeficiencies. Definitive diagnosis rests on the visualization of the parasites, ideally by broncho-alveolar lavage. If the lavage is negative and the patient deteriorates, an open lung biopsy is the next best diagnostic method. Serological methods are unreliable. Treatment with trimethoprim-sulfamethoxazole (TMP) should be instituted as early as possible: a serum level of TMP between 5 and 10 micrograms/ml should be attained. If no improvement occurs after three days, pentamidine should be substituted. Systematic chemoprophylaxis should be given to all high-risk patients.