The relationship between disease pattern and disease burden by chest radiography, M. tuberculosis Load, and HIV...

We evaluated the impact of HIV coinfection on the chest radiographic pattern and extent of disease and its relation to the load of Mycobacterium tuberculosis in Ethiopian out-patients with pulmonary tuberculosis.

A total of 168 patients with cultureverified pulmonary tuberculosis had their chest X-rays (CXR) reviewed for the site, pattern, and extent of disease and the findings were correlated to (a) the mycobacterial culture count and bacillus load after sputum concentration and (b) the HIV status of the patients.

HIV-positive patients were less likely to have cavitary disease (p < 0.001) and more likely to have pleural effusion (p = 0.08), miliary (p < 0.05), and interstitial (p < 0.01) patterns. A total of 15 (9.2%) patients had normal chest X-rays. HIV-infected patients had a CXR classified as normal or with minimal involvement (p = 0.059) and a reduced mycobacterial colony count (p = 0.002) compared to HIV-negative patients. Middle and lower lung involvement were more common in HIV-positive patients.

CXR findings in the setting of an underlying HIV infection tend to be more atypical and could present as either normal or with minimal involvement. In general, HIV-positive patients had lower colony count of M. tuberculosis than HIV-negative patients. Of particular interest is the finding of a large number of normal chest X-rays in HIV-infected patients. With the rising incidence of both tuberculosis and HIV infection in Ethiopia, the finding of a normal chest X-ray and a negative smear poses a challenge for the diagnosis of pulmonary tuberculosis.