HIV-TB: epidemiology, clinical features and diagnosis of smear-negativeTB.

TB remains an important public health problem in the world that has been exacerbated by the HIV epidemic. In 2000, while 9% of new TB infections worldwide were attributable to HIV, in Sub-Saharan Africa--a region with higher HIV prevalence--about 31% of new TB cases were attributable to HIV. Clinical presentation of TB in HIV-infected individuals depends on the severity of the suppression of immunological functions. In patients in early stages of HIV infection, TB clinical presentation resembles that of HIV-negative individuals with more pulmonary involvement and localized lesions. With the progressive suppression of immunological functions, TB tends to be more generalized affecting more than one organ. Classic TB symptoms are non-specific and may result in delayed diagnosis or misdiagnosis. Diagnosis of smear negative pulmonary TB is based on clinical and radiological features. Sputum culture and rapid diagnostic tests based on polymerase chain reaction can be used where available.