Pneumocystis jiroveci pneumonia in rheumatic disease: a 20-year single-centre experience

Pneumocystis jiroveci pneumonia (PJP) is an opportunistic infection with high mortality among patients with underlying rheumatologic conditions. Given the paucity of prospective data to guide treatment, clinical guidelines to initiate PJP prophylaxis are based on expert opinion and identify patients on ≥20 mg daily prednisone for ≥4 weeks duration for treatment. Herein we describe the PJP experience in rheumatic disease over a 20-year period at a single academic medical centre to investigate this 20 mg threshold and risk associated with lymphocyte counts, co-existing lung disease and immunosuppressive medications.

We conducted a retrospective review of all admitted patients who received a PJP or PCP ICD-9 code (136.3) from January 1996 through October 2015.

Twenty-one cases of confirmed PJP (by immunofluorescence or polymerase chain reaction) were reviewed, averaging to one case/year. The most common underlying rheumatologic conditions were inflammatory myopathy, lupus, and granulomatosis with polyangiitis. None of these 21 patients was receiving PJP prophylaxis upon admission. Eighteen (86%) were receiving ≥20 mg prednisone daily at the time of PJP diagnosis. Of the 3 treated with <20 mg prednisone, all received concomitant immunosuppressive medications, 2 with cyclophosphamide. Overall, there was a 43% (9/21) mortality rate. Immunosuppressant medication use, interstitial lung disease, or lymphocyte count did not impact mortality risk.

PJP portends high mortality yet is a largely preventable complication of rheumatic disease treatment. Consideration to initiate prophylaxis should be made for patients exceeding the daily 20 mg prednisone threshold, and those receiving cyclophosphamide.