Neumocistosis. Abordaje terapéutico y profiláctico

Abstract

Pneumocystosis is an infectious disease caused by Pneumocystis carinii (jiroveci). It affects mainly subjects with primary or secondary cellular immunodeficiency. During the 1940's, after the end of World War II, several cases of pneumocystosis were reported in premature newborns and malnourished children. Subsequently the disease was detected in patients with cancer, haematologic diseases, and those with organ transplants (both solid organs and bone marrow transplants). With the appearance of AIDS in the 1980's the number of reported cases of pneumocystosis increased; it became the first opportunistic infection diagnosed in these patients. Currently, more than 70% of patients with AIDS present with a pneumocystosis that may be fatal in up to 100% of the cases; therefore, early medical treatment and prophylaxis will have a beneficial effect on prognosis. In this paper we review the drugs and dosages used both for treatment and prophylaxis of pneumocystosis. Trimetoprim-sulfametoxazole is still the drug of choice. In patients who do not tolerate trimetoprim sulfametoxazole, a suitable alternative is intravenous pentamidine. Pentamidine aerosol has a limited therapeutic effect. Atovacuone is indicated in patients with mild to moderate pneumocystosis. Trimetrexate is a dehydrofolate reductase inhibitor that must be administered together with folinic acid; it is successful in 63 to 71% of the patients with AIDS and pneumocystosis. Steroids are used as support therapy in moderate to severe cases. Prophylaxis has specific indications, whether as primary (after the first episode of the disease) or secondary (after several episodes of the disease). The number of CD4+ T cells is also an important indicator for starting prophylaxis. Criteria for initiating prophylaxis in the pediatric patient take into consideration the number of previous episodes of pneumocystosis and the age of the patient.