Management of pulmonary tuberculosis suspects with negative sputum smears and normal or minimally abnormal chest radiographs in resource-poor settings

SETTING: Queen Elizabeth Central Hospital, Blantyre, Malawi. OBJECTIVES: 1) To determine the proportion of pulmonary tuberculosis (PTB) suspects with negative sputum smears and a normal/minimally abnormal chest radiograph (CXR) who are culture-positive for Mycobacterium tuberculosis, and 2) to determine how many develop smear or radiographic evidence of PTB (TB CXR) during follow-up. METHODS: PTB suspects with negative sputum smears and a normal/minimally abnormal CXR were given a second course of antibiotics and followed up at 3-week intervals over 3 months with repeat sputum smears and chest radiography. RESULTS: Of 79 patients (38 men and 41 women, mean age 33 years) with negative smears and a normal/minimally abnormal CXR, 16 (21%) were culture-positive for M. tuberculosis. Of 15 culture-positive patients who were alive and attended follow-up, seven (47%) developed a TB-CXR by 3 months. Of 41 culture-negative patients who were alive and attended follow- up, 13 (32%) developed a TB-CXR, including one patient who became sputum smear-positive. TB-CXRs were found only in patients with a cough. CONCLUSION: TB suspects with negative smears and normal/minimally abnormal CXRs in high human immunodeficiency virus (HIV) prevalent countries should be given a second course of antibiotics. If cough improves, patients can be advised not to return for further follow-up. If cough continues, patients should return for further follow-up with sputum smear examination and chest radiography. Approximately 50% of those who have culture-positive PTB will develop a TB- CXR by 3 months and can be identified if radiographic facilities are available.