Tuberculosis Chapter 158 offers a concise overview of the pathophysiology and treatment of TB, which is closely linked to HIV infection in much of the world. Indeed, a substantial proportion of the resurgence of TB registered in southern Africa may be attributed to HIV co-infection. Even before the advent of HIV, however, it was estimated that fewer than half of all cases of TB in developing countries were ever diagnosed, much less treated. Primarily because of the common failure to diagnose and treat TB, international authorities devised a single strategy to reduce the burden of disease. The DOTS strategy (directly observed. | Chapter 002. Global Issues in Medicine Part 6 Tuberculosis Chapter 158 offers a concise overview of the pathophysiology and treatment of TB which is closely linked to HIV infection in much of the world. Indeed a substantial proportion of the resurgence of TB registered in southern Africa may be attributed to HIV co-infection. Even before the advent of HIV however it was estimated that fewer than half of all cases of TB in developing countries were ever diagnosed much less treated. Primarily because of the common failure to diagnose and treat TB international authorities devised a single strategy to reduce the burden of disease. The DOTS strategy Jirectly observed therapy using .vhort-course isoniazid- and rifampin-based regimens was promoted in the early 1990s as highly cost-effective by the World Bank the WHO and other international bodies. Passive case-finding of smear-positive patients was central to the strategy and an uninterrupted drug supply was of course deemed necessary for cure. DOTS was clearly effective for most uncomplicated cases of drug-susceptible TB but it was not long before a number of shortcomings were identified. First the diagnosis of TB based solely on smear microscopy a method dating from the late nineteenth century is not sensitive. Many patients with pulmonary TB and all patients with exclusively extrapulmonary TB are missed by smear microscopy as are most children with active disease. Second passive case-finding relies on the availability of health care services which is uneven in settings where TB is most prevalent. Third patients with multidrug-resistant MDR TB are by definition infected with strains of Mycobacterium tuberculosis resistant to isoniazid and rifampin thus exclusive reliance on these drugs is ineffective in settings in which drug resistance is an established problem. The crisis of antibiotic resistance registered in . hospitals is not confined to the industrialized world or to bacterial infections. In some settings a .
