A close and complex association exists between tuberculosis and human immunodeficiency virus (HIV). Tuberculosis is the leading cause of death in people with HIV and also has an adverse effect on HIV progression. The recurrent epidemic of HIV in many African countries has increased the burden of tuberculosis many folds leading to an epidemic of tuberculosis so to say, in those countries. Similarly, in several developed countries where there had been a regular decline in the prevalence of tuberculosis, the situation has reversed due to the pandemic of HIV/AIDS.
HIV infection has been identified as the highest risk factor that triggers the reactivation of latent infection with tuberculosis. This is because decrease in immunological control of latent TB infection greatly increases the risk of reactivation of active infection.
Also a decrease or impairment in the body immunological status exposes an individual to infection with atypical mycobacteria. Sentinel surveillance in Nigeria in 2001 showed the prevalence of HIV among TB patients to be 19.1%. The HIV sero-prevelance in TB-patients world wide has underscored the urgent need to screen all suspected TB patients for HIV infection. Consequently, all suspects and TB patients should be offered voluntary counseling and testing (VCT).
- SPUTUM MICROSCOPY/CULTURE: Confirmation of diagnosis is by demonstration of tubercle bacilli in sputum smear or by culture. Whenever pulmonary tuberculosis is suspected, three sputum specimen should be collected and sent for direct smear microscopy for acid fast bacilli (AFB). This is usually demonstrated by the ziehl-Neelsen method, using hot carbol fuschsin stain.
- CHEST X-RAY: X-ray diagnosis of pulmonary tuberculosis is unreliable because several chest diseases can produce radiographic shadows that look like tuberculosis. The frequent habit of treating radiographic shadows should be discouraged.
- RADIOGRAPHY AND CULTURE: Extra pulmonary tuberculosis is diagnosed by radiography and culture or histology of specimen from the affected site.
- TUBERCULIN TEST:- Tuberculin test is of limited value in the diagnosis of tuberculosis in adults in highly endemic areas. A positive tuberculin test (10mm and more) is useful in the diagnosis of tuberculosis in unvaccinated children. A negative tuberculin test is an indication that the patient has had no previous exposure to tubercle bacilli, although occasionally the test is negative in certain conditions with suppressed immunological response and in patients with overwhelming infection who have no acquired immunity.
PROBE DETECTION METHODS:- New diagnostic tests based on probe detection methods targeting mycobacteria DNA and RNA have been identified. This method is rapid and simple to perform, giving results in adults in 1-2 hours with accuracy estimated to be above 90%.