What are the possible causes of cough in an HIV-infected patient?
The CD4 cell count is crucial information in determining the cause of cough. In patients with CD4 cell counts >200/mm3, viral upper respiratory infections, bacterial pneumonia (caused by S. pneumoniae or H. influenzae most commonly), tuberculosis (TB), and sinusitis with post-nasal drip are all important causes of cough. Bacterial bronchitis is more common in patients with HIV than in non-HIV-infected patients. In patients with low CD4 cell counts (<200/mm3) Pneumocystis carinii pneumonia must be considered. The risk of PCP is markedly diminished if the patient is taking trimethoprim-sulfamethoxazole for PCP prophylaxis. The cough that occurs with PCP is usually dry and persistent and will usually have been present for several weeks before a patient seeks evaluation. Fungal disease due to cryptococcus, histoplasmosis, or coccidioidomycosis is more common with lower CD4 cell counts. What workup is appropriate? In patients with CD4 cell counts >200/mm3 the history and physical exam shoul
