Pneumocystis carinii pneumonia in patients being registered for smear-negative pulmonary tuberculosis in Malawi

The National TB Control Programme of Malawi registers and treats large numb ers of patients with chronic cough for smear-negative pulmonary tuberculosi s (PTB). Smear-negative PTB is diagnosed according to clinical and radiogra phic criteria, as mycobacterial cultures are not routinely available. In an area of high HIV seroprevalence there is a concern that other opportunisti c infections apart from TB, such as Pneumocystis carinii, may be missed owi ng to lack of diagnostic facilities. The aims of this study were to investi gate (i) the extent of P. carinii pneumonia (PCP) in patients about to be r egistered for smear-negative PTB; (ii) whether there were any clinical or r adiological features that could help identify PCP in the absence of more de tailed investigations; and (iii) the treatment outcome of PCP patients. A c ohort of 352 patients who were about to be started on treatment for smear-n egative PTV were investigated further in 1997-99 by clinical assessment, HI V testing and bronchoscopy. HIV sero-prevalence was 89% (278/313). A total of 186 patients underwent bronchoscopy and bronchoalveolar lavage, and PCP was diagnosed by indirect immunofluorescence or polymerase chain reaction i n 17 (9%) of this subgroup. Dyspnoea was significantly more common in PCP c ases compared to non-PCP cases (RR 1.35; 95% Cl 1.24-1.48; P = 0.008), but discrimination between the groups was difficult using clinical criteria alo ne. The outcome of PCP cases was poor despite management with high-dose co- trimoxazole and secondary co-trimoxazole prophylaxis, with a median surviva l of 4 months (25-75% range: 2-12 months).