Lung fibrosis in deceased HIV-infected patients with Pneumocystis pneumonia

Background. Pneumocystis pneumonia (PcP) is one of the most common opportunistic infections found in patients with HIV. The prognosis if ventilation is required is poor, with mortality of 36 - 80%. Although more recent studies have shown improved survival, our experience has been that close to 100% of such patients die, and we therefore decided to investigate further. Methods. All patients with confirmed or suspected PcP who died owing to respiratory failure were eligible for the study. Where consent was obtained, trucut lung biopsies were performed post mortem, stored in formalin and sent for histopathological assessment. Results. Twelve adequate lung biopsies were obtained from 1 July 2008 to 28 February 2011 – 3 from men and 9 from women. The mean age was 34.7 years (range 24 - 46), and the mean admission CD4 count was 20.8 (range 1 - 68) cells/ìl and median 18.5 cells/ìl. All specimens demonstrated typical PcP histopathology; in addition, 9 showed significant interstitial fibrosis. Three had co-infection with cytomegalovirus (CMV), two of which had fibrosis present. There was no evidence of TB or other fungal infections. Conclusion. The high mortality seen in this cohort of PcP patients was due to intractable respiratory failure from interstitial lung fibrosis. Whereas the differential includes ventilator induced lung injury, drug resistance or co-infections, we suggest that this is part of the disease progression in certain individuals. Further studies are required to identify interventions that could modify this process and improve outcomes in patients with PcP who require mechanical ventilation.