How does HIV Infection influence the diagnosis of TB?
In most cases, the clinical presentation of tuberculosis among patients with HIV is indistinguishable from other cases. However, some may show a bizarre pattern with a higher proportion of cases tending to have a negative sputum smear. In spite of that, sputum smear examination remains an essential component in the diagnosis of tuberculosis in countries where HIV infection is common becauseof its ability to identify infectious cases. The diagnosis of TB in HIV-positive patients is more difficult for three main reasons: 1. The sensitivity of the direct sputum smear examination is a reduced in HIV-positive patients. Compared to HIV-negative patients with pulmonary TB, a lesser proportion of HIV-positive patients with pulmonary TB will have positive sputum smears; 2. X-ray abnormalities, which are not specific for TB in HIV-negative patients, are even more non-specific in HIV-infected with only minor abnormalities on chest X-ray orwith abnormalities which do not look like classical TB, an
