Histoplasma Capsulatum Infections

GENERAL PRINCIPLES

• The severity of infection depends on the degree of the patient's immunosuppression.

• Histoplasmosis often occurs in AIDS patients who live in endemic areas such as the Mississippi and Ohio River Valleys.

• Such infections are usually disseminated at the time of diagnosis.

DIAGNOSIS

• Suspect histoplasmosis in patients with fever, hepatosplenomegaly, and weight loss.

• Pancytopenia develops because of bone marrow involvement.

• Diagnosis is made by a positive culture or biopsy demonstrating 2-4 #956;m budding yeast, but the urine and serum Histoplasma antigens can also be used for diagnosis and to monitor treatment.

TREATMENT

• Disseminated disease is treated with liposomal amphotericin B, 3 mg/kg IV daily for 2 weeks or until the patient clinically improves, followed by itraconazole, 200 mg PO bid indefinitely.

• CNS disease is initially treated with liposomal amphotericin B, 5 mg/kg IV daily for 4-6 weeks, before starting itraconazole.

• Itraconazole absorption should be documented by a serum drug level. Liquid itraconazole is preferred because of improved absorption; however, it can be expensive and difficult to obtain.

• Discontinuation of itraconazole is possible if sustained increase in CD4 count is observed gt;100-200 cells7#956;L for more than 6 months.