PNEUMOCYSTIS-CARINII INFECTION - CURRENT TREATMENT AND PREVENTION

Pneumocystis carinii is a common cause of pneumonia in individuals who are immunosuppressed by HIV infection. Use of molecular biological te chniques show that P. carinii is a fungus and that infection in man is not a zoonosis. Invasive tests such as sputum induction or bronchosco py are used to make the diagnosis of P. carinii pneumonia. Life long p rimary prophylaxis is given to HIV positive individuals with CD4+ lymp hocyte counts <0.20 x 10(9)/L or a CD4: total lymphocyte ratio of <1.5 , constitutional symptoms, or with other AIDS defining diseases. Secon dary prophylaxis is given after a first episode to prevent a recurrenc e. First choice for primary and secondary prophylaxis is oral co-trimo xazole 960 mg od or three times week. In patients who are intolerant t o co-trimoxazole, nebulised pentamidine or dapsone (with or without py rimethamine) are second and third choices. In a patient with acute PCP disease, severity should be assessed using clinical, radiographic and blood gas criteria as those with moderate or severe disease will bene fit from adjuvant glucocorticoids. Co-trimoxazole (120 mg/kg/day in di vided doses for 21 days) is first choice therapy for PCP of all degree s of severity. In patients who fail to respond to co-trimoxazole or wh o are intolerant to it, second line treatment is iv pentamidine in tho se with severe disease and oral dapsone with trimethoprim, oral clinda mycin with primaquine or iv pentamidine in those with mild or moderate ly severe disease.