Pneumocystis carinii pneumonia presenting as a fever of unknown origin in a patient without AIDS

Pneumocystis Carinii pneumonia (PCP) remains an opportunistic infection that causes substantial morbidity and mortality in patients who have impaired immune function. PCP in patients who do not have AIDS usually manifests in a more fulminant manner than in patients with AIDS. In recent years, PCP has been reported increasingly in patients with connective tissue disorders. The role of corticosteroids in inducing PCP is well established in humans and animals, though information is currently lacking about the exact mechanism of induction, frequency, dosage, and duration of corticosteroid therapy that predisposes the development of PCP across a variety of patient groups. Until earlier diagnosis and a better understanding of who is at risk are readily available, health care providers need to consider the diagnosis of PCP early in the clinical course of any patient who receives systemic steroid therapy. We report a case of PCP in a patient who took oral steroid treatment for 2 months for suspected connective tissue disorder. The patient presented with a fever of unknown origin. The case is unusual because the patient's serial chest x-ray and gallium scan yielded normal findings and no suggestive respiratory signs or symptoms were found. The only suggestive finding was a consistently elevated serum lactate dehydrogenase level. The diagnosis was established by the identification of Pneumocystic carinii in bronchoalveolar lavage fluid.