ABSTRACT
Pneumocystis jirovecii, formerly known as Pneumocystis carinii, is an atypical fungal pathogen best known for causing Pneumocystis jirovecii pneumonia (PCP). The epidemiology of PCP is changing such that patients without HIV infection now comprise the largest subset of individuals diagnosed with PCP. While those with hematologic malignancies and organ transplants are at greatest risk for non-HIV-related PCP, this review will focus on PCP in patients with solid tumors. They are at risk for PCP due to their chemotherapy regimens and use of steroids in the management of various complications of treatment, and possibly because of the immunosuppressive effect of the cancer itself. In particular, patients with solid tumors being treated for metastatic spinal cord compression are at great risk for PCP. Patients with solid tumors and PCP face greater mortality than those with HIV infection. Multiple reviews have attempted to describe the ideal regimen of corticosteroids for metastatic spinal cord compression, but there is little consensus. We present 2 cases of patients with metastatic spinal cord compression due to prostate cancer undergoing radiation therapy and treatment with corticosteroids. These cases highlight the difficulties in predicting the length of corticosteroid therapy and the dangers that patients face without appropriate prophylaxis. This article will also provide a review of the current guidelines for PCP prophylaxis in patients undergoing treatment for metastatic spinal cord compression. We recommend empiric treatment with trimethoprim-sulfamethoxazole or dapsone in those patients with a sulfa allergy in all patients with solid tumors when any high-dose steroids are started for the treatment of metastatic spinal cord compression. Further research is needed to assess the epidemiology of PCP in patients with solid tumors and additional trials are necessary to refine PCP prophylaxis.
