Pulmonary Tuberculosis in HIV-Infected Patients Presenting with Normal Chest Radiograph and Negative Sputum Smear

Abstract

Background: HIV-infected patients with pulmonary tuberculosis exhibit atypical radiological presentation and negative sputum smear more frequently than their HIV-negative counterparts.

Patients and Methods: We performed a retrospective study based on a chart review of 146 HIV-infected patients with pulmonary symptoms and culture-proven pulmonary tuberculosis. We compared clinical characteristics and the outcome in 71 patients (49%) with positive sputum smear (SS+), 62 patients (42%) with negative sputum smear/abnormal chest X-ray (SS−/CXR+) and 13 patients (9%) with negative sputum smear/normal chest X-ray (SS−/CXR−). Patients were enrolled form January 1987 to December 1998, and were followed up until December 1999.

Results: On hospital admission the three groups of patients examined did not differ significantly in demographic characteristics, degree of immunosuppression or Mycobacterium tuberculosis drug-susceptibility pattern. SS−/CXR− patients were significantly less likely to present with prolonged fever and dyspnea. Median survival was shorter for SS−/CXR− patients (6.4 months vs. 20.2 and 18.8 months in the other two groups). In multivariate analysis, SS−/CXR− patients had a significantly increased risk of death (hazard ratio 3.0, 95% confidence interval, 1.4 to 6.4, p = 0.004) compared to SS+ patients. This increase in risk was no longer statistically significant when initiation of antituberculous therapy within 8 weeks from the collection date of the first specimen yielding M. tuberculosis was included in the multivariate model.

Conclusion: Decreased survival was observed in HIV-infected patients with pulmonary tuberculosis and with both negative sputum smear and normal chest X-ray presentation. This may primarily be a result of delayed tuberculosis diagnosis and initiation of antituberculous therapy. The latter delay may also lead to a faster progression of HIV infection in SS−/CXR patients, in whom diagnostic oversight may be common.