Histoplasmosis

Histoplasma capsulatum

Treatment

In high endemic regions (French Guiana), histoplasmosis is the most prevalent OI

Diagnosis: antigen detection in blood, urine or broncho-alveolar fluid, OR positive microscopy, OR mycological culture of blood, urine, broncho-alveolar fluid, CSF or tissue biopsy, OR PCR in blood or other clinical samples. Commercial antigen assays are not available in all Europeans countries and PCR techniques are being developed but are not routinely available. Aspergillus galactomanan assays may be helpful to diagnose disseminated infections as cross reactivity occurs

Note: CSF, which shows typically a lymphatic pleocytosis, is usually microscopy and culture negative. Detection of histoplasma antigen or antibody is more sensitive. Though, a clinical diagnosis is possible in case of negative Histoplasma antigen or antibody in CSF, if disseminated histoplasmosis is present and CNS infection is not explained by another cause.
Fluconazole should not be used for treatment of histoplasmosis. Little clinical evidence is available for the use of voriconazole or posaconazole. Be aware of interactions of azoles with ARVs, see Drug-drug Interactions Between ARVs and Non-ARVs. Measurement of plasma concentration of itraconazole is advised to guide optimal treatment, and itraconazole oral suspension should be preferred due to better bioavailability. Serum itraconazole concentration should be at least 1 mcg/mL if measured by high-performance liquid chromatography (HPLC)

  Drug / Dose Comments
Severe disseminated histoplasmosis  Induction therapy:
liposomal amphotericin B 3 mg/kg/day iv
For 2 weeks or until clinical improvement
Consolidation therapy:
itraconazole 200 mg tid po for 3 days, then 200 mg bid po
For at least 12 months
Moderate disseminated histoplamosis itraconazole 200 mg tid po for 3 days, then 200mg bid po For at least 12 months
Histoplasma meningitis  Induction therapy:
liposomal amphotericin B 5 mg/kg qd iv
For 4-6 weeks
Consolidation therapy:
itraconazole 200 mg bid-tid po
For at least 12 months and until resolution of abnormal CSF findings. Measure plasma concentration of itraconazole

Secondary Prophylaxis/ Maintenance Therapy

Stop: if CD4 count > 150 cells/μL and HIV-VL undetectable over 6 months, negative fungal blood cultures, histoplasma antigen < 2μg/L and > 1 year treatment

Consider long-term suppressive therapy in severe cases of meningitis and in cases of relapse despite adequate treatment

Drug / Dose
itraconazole 200 mg qd po