The aetiology of pulmonary infections among AAFB sputum smear negative HIV adults presenting to Mulago hospital

Abstract

Background: Pulmonary infections are an important cause of complications in up to 60% of HIV infected patients during the course of their disease. Tuberculosis (TB) is a common cause of such infections. Sub-Saharan Africa has two thirds of the world's infection (21 million people infected). Dual infection with HIV and TB is common and sputum smear negative TB is a common finding in advanced AIDS disease. Thirty percent of sputum Acid Alcohol Fast Bacilli (AAFB) smear negative patients have been found to have TB. A previous bronchoscopic study by serwadda and others on 4a AIDS patients with pulmonary disease found TB in 9 (22.5%), Kaposia's sarcoma in 6 (15%), Pyogenic bacteria in 4 (10%) and Cryptococcus in 3 (7.5%) of the patients, leaving 45% of patients without identifiable cause of their pulmonary disease. Similarly other African studies have not been able to identify up to 45% causes of respiratory disease. Purpose: This study was conducted to determine the prevalence and pattern of pulmonary infections among sputum smear AAFB negative HIV seropositive patients with pulmonary symptoms and pulmonary infiltrates on chest radiograph. The causative agents were to be identified and their relative proportions determined. Materials and Methods: Consecutive adult patients admitted to Mulago Hospital medical wards with respiratory symptoms of at least 3 weeks with infiltrates on chest radiograph and no previous history of TB treatment were enrolled into the study. Two spot and one early morning sputa were screened for AAFB. Pre-test counselling was done before HIV serology and post-test counselling was done before giving the results. Chest radiographs were done and reported on by a radiologist. Patients who were AAFB negative and HIV positive were requested to participate in the study. Consenting patients had bronchoscopy done on them and bronchoalveolar lavage (BAL) fluid obtained. The BAL fluid was stained for AAFB and for P.carinii organisms. It was also cultured for pyogenic bacteria, fungi and for mycobacteria. Data collection was done using predesigned forms, after which the data was entered and analysed using the Epi lNFO 6 statistical programme. Results: One hundred and ninety eight patients were screened for entry into the study. Forty eight of these patients were sputum smear positive for AAFB and were started on TB treatment. Of the remaining 150, 67 were excluded for various reasons leaving 83 patients who met inclusion criteria and had bronchoscopy done and BAL fluid obtained. Thirty-two (38.6%), were found to have P. carinii infection, 20 (24.1%) patients had TB, 9 (10.8%) patients had PKS and pyogenic bacteria were identified in 7 (8.4%) patients. No fungi were identified. No aetiological diagnosis was made in 24 (29.9%) patients. Nine (10.8%) patients had more than one diagnosis. Conclusions: By the use of bronchoscopy, it was possible to identify PCP (38.6%), PTB (24.1%), PKS (10.8%) and pyogenic bacteria (8.4%) among AAFB sputum smear negative, HIV positive adults presenting to Mulago Hospital with pulmonary symptoms.