Therapy
Prophylactic therapy is not currently recommended for the prevention of cryptococcosis in immunocompromised patients. For patients who have HIV-1 infection and active pulmonary disease without concurrent CNS disease, therapy with azoles, such as fluconazole(Drug information on fluconazole) 200 to 400 mg/d, is a reasonable option.⁷ However, patients who are severely ill should receive amphotericin B(Drug information on amphotericin b). Secondary prophylaxis should be continued until significant immune reconstitution from antiretroviral therapy (ART) is established.

For patients who have HIV-1 infection and CNS or disseminated disease, the recommended initial treatment is intravenous amphotericin B (0.7 to 1 mg/kg/d) combined with oral flucytosine(Drug information on flucytosine) (100 mg/kg/d in 4 divided doses) for 2 weeks in patients with normal renal function. This regimen can be switched to oral fluconazole 400 mg/d for an additional 8 weeks if significant clinical improvement occurs and CSF cultures are negative after repeat lumbar puncture. Lipid formulations of amphotericin B may be useful in patients who have renal insufficiency or who are at high risk for the development of renal failure, although the optimal dosage has not been determined.^4,7

Treatment options in immunocompromised patients who are not HIV-1–infected have not been well studied. It is recommended that all immunocompromised patients-including patients with hematological malignancy and transplant recipients- with non-CNS pulmonary and extrapulmonary disease be treated in the same fashion as patients with CNS disease.⁷ Every attempt to improve the immunity of the host should be made, including decreasing immunosuppression, if feasible.

HISTOPLASMOSIS

Histoplasma capsulatum
is a dimorphic fungus that can cause infections in both immunocompetent and immunocompromised patients. In the United States, H capsulatum is endemic to the Mississippi and Ohio river valleys and localized areas near these regions. It grows well in soil that contains large amounts of bird or bat guano.⁸

Disease occurs either as a result of new infection after an environmental exposure or as a result of reactivation of latent infection if cellular immune function wanes. Weakened cellular immune function is the presumed cause of disease recurrence in areas where H capsulatum is not endemic.⁹ T-cell–mediated immune responses play an important role in whether a person fends off disease caused by infection with this organism; however, even in patients with adequate cell-mediated immunity, H capsulatum can maintain foci in various organs, ¹⁰ thus allowing for reactivation of infection when cell-mediated immunity is disrupted by illness or medication use.

Histoplasmosis occurs in 2% to 5% of patients with HIV/AIDS who are not receiving ART and who either currently live or have lived in areas where H capsulatum is endemic. Localized pulmonary disease might occur in patients with a CD4⁺ lymphocyte count of more than 300/μL, whereas disseminated disease usually occurs in patients with a CD4⁺ lymphocyte count of less than 150/μL.^4,11

Histoplasmosis is uncommon in patients who have hematological malignancies and in hematopoietic stem cell transplant (HSCT) and SOT^12,13 recipients; however, it can be life-threatening when it does occur. Disseminated disease has been reported in renal^13,14 and liver¹³ transplant recipients. Donor-transmitted disease has been reported but is a rare phenomenon.¹⁵