Epidemiology and diagnosis of tuberculosis. Recognition of at-risk patients is key to prompt detection.

The increasing incidence of TB and HIV infection and the emergence of drug resistance worldwide poses a major threat, particularly in developing nations. In an era with an increasing number of Americans living with HIV infection or with immunosuppression associated with chemotherapy or organ transplants, the possibility of primary M tuberculosis and of unusual clinical and radiographic presentations of reactivation disease is becoming more common. The primary care physician plays a crucial role in recognizing high-risk patients and initiating prompt isolation and evaluation.