An approach to the problems of diagnosing and treating adult smear-negative pulmonary tuberculosis in high-HIV-prevalence settings in sub-Saharan Africa

The overlap between the populations in sub-Saharan Africa infected with hum an immunodeficiency virus (HIV) and Mycobacterium tuberculosis has led to a n upsurge in tuberculosis cases over the last 10 years. The relative increa se in the proportion of notified sputum-smear-negative pulmonary tuberculos is (PTB) cases is greater than that of sputum-smear-positive PTB cases. Thi s is a consequence of the following: the association between decreased host immunity and reduced sputum smear positivity; the difficulty in excluding other HIV-related diseases when making the diagnosis of smear-negative PTB; and an increase in false-negative sputum smears because of overstretched r esources. This article examines problems in the diagnosis and treatment of smear-negative PTB in high-HIV-prevalence areas in sub-Saharan Africa. The main issues in diagnosis include: the criteria used to diagnose smear-n egative PTB; the degree to which clinicians actually follow these criteria in practice; and the problem of how to exclude other respiratory diseases t hat can resemble, and be misdiagnosed as, smear-negative PTB. The most impo rtant aspect of the treatment of smear-negative PTB patients is abandoning 12-month "standard" treatment regimens in favour of short-course chemothera py. Operational research is necessary to determine the most cost-effective appr oaches to the diagnosis and treatment of smear-negative PTB. Nevertheless, substantial improvement could be obtained by implementing the effective mea sures already available, such as improved adherence to diagnostic and treat ment guidelines.