Refractory hypoxia in an HIV-infected patient--a diagnostic challenge

A 39-year-old man with HIV presented to the emergency department for evaluation of dyspnea accompanied by fever, diffuse chest discomfort, dry cough, and fatigue for past 1 week. The patient described his dyspnea as exertional progressing over 1 week to rest dyspnea. He was prescribed antiretroviral therapy but was noncompliant. He had no paroxysmal nocturnal dyspnea, orthopnea, rash, oral thrush, or diarrhea. His last record CD4+ lymphocyte count and HIV viral load were 43 cells/mm3 and 178,0000 copies/mL, respectively. Vital signs included a temperature of 101°F, heart rate of 115 beats per minute, respiratory rate of 16 per minute, and pulse oxygenation of 91% on room air. Lung examination revealed decreased breath sounds bilaterally, and the remainder of the examination was unrevealing. Laboratory findings revealed leukocytosis and increased serum lactate dehydrogenase of 577 U/L (90-190 U/L), and chest radiograph showed a right lower lobe infiltrate and perihilar, bilateral interstitial infiltrates (Fig. 1A).