Pneumocystis carinii pneumonia in HIV negative patients with primary brain tumors.

Background: Pneumnocystis carinii pneumonia (PCP) is an opportunistic infection with rather adverse outcomes. An unexpected increase in cases of PCP was noted in the brain tumor population at the Johns Hopkins Hospital (JHH) in 2000. This prompted the present review of the clinical features and risk factors for PCP in the human immunodeficiency virus (HIV) negative brain tumor population.

Methods: The study was located at the JHH. A retrospective review of medical records was done to identify patients with discharge diagnosis of PCP from 1980 to 2001. Patients who were HIV positive were excluded. A detailed analysis was done of patients with brain tumors.

Results: From 1980 to 2001, 468 cases of PCP were identified, diagnosed histologically or clinically, of which 110 were patients with an underlying malignancy. Of the 110 cases 15 were seen in the brain tumor population. Of these, 6 patients were seen in 2000 and one in early 2001. Three of these had primary central nervous system (CNS) lymphoma (PCNSL) on high dose methotrexate. Eight of the fifteen episodes (53.3%) were fatal despite institution of antibiotics and supportive therapy.

Conclusion: The incidence and mortality due to Pneumocystis carinii among the brain tumor population is increasing. While corticosteroids are known immunosupressants, prescribing patterns for these medications has not changed lately. However, high dose methotrexate is now being used in PCNSL and could be a complicating factor. Since effective prophylaxis exists, it should be considered in patients with brain tumors receiving high dose steroids, high dose methotrexate or with lymphopenia.