Cause: Pneumocystis carinii, reclassified as a fungus from protozoan status in 1988
Pathophys:Diffuse interstitial pneumonitis
Opportunistic, from other people harboring (epidemics in tumor clinicAnn IM 1975;82:772)
In patients with depressed immunologic responses, eg, hypogammaglobulinemia, "premies," hematopoietic malignancy, immunosuppression, AIDS (vast majority of patients with pneumocystis have AIDS), elderly (Nejm 1991;324:246)
Die in weeks without rx (50%), with rx mortality ~3%; those requiring ventilator have a 25% survival to hospital d/c (Jama 1995;273:230)
Osteomyelitis rarely (Nejm 1992;326:999) r/o other opportunistics (Acquired Immune Deficiency Syndrome (AIDS))
Lab:
Bact:Hypertonic saline-induced sputum (Ann IM 1988;109:7), stain with Giemsa (72% sens), toluidine blue (80% sens), or with indirect immunofluorescence (92% sens) (Nejm 1988;318:589)
Path: Fiberoptic bronchoscopic bx, lavage, brushings
Xray:Chest shows diffuse interstitial infiltrate, starts perihilar, 98% bilateral. Gallium scan shows hot lungs even with neg plain films, but 50% false positives including sarcoid patients (Nejm 1988;318:1439)
Rx:
(Med Let 1995;37:87; Nejm 1992;327:1853; Ann IM 1988;109:280)
Preventive (Nejm 1995;332:693; Ann IM 1995;122:755): Isolation of infected from other susceptible patients?; under CD4 of 100, Tm/S better than dapsone, which is better than pentamidine.
Treatment: