DISSEMINATED HISTOPLASMOSIS IN IMMUNOCOMPETENT INDIVIDUALS- NOT A SO RARE ENTITY

Abstract

Introduction:

Histoplasmosis is a rare fungal disease caused by dimorphic fungi Histoplasma capsulatum. The causative fungus is present in soil, infects through inhalation and manifests in three main types-acute primary, chronic cavitary and progressive disseminated Histoplasmosis. Disseminated Histoplasmosis (DH) is defined as a clinical condition where fungus is present in more than one location. Among the forms of histoplasmosis, DH is the rarest and generally found in immune-compromised individual.

Here we are presenting our experiences of the series of cases of Disseminated Histoplasmosis in immune-competent individuals who have been diagnosed in our institute in last 5 years.

Materials and methods:

This is a single centre retrospective observational study, from May 2009 to April 2014. Only cases with Disseminated Histoplasmosis in otherwise healthy immune-competent individuals were included in the study. The Histoplasmosis is confirmed by either presence of Histoplasma in biopsy specimen from extra-pulmonary organ or by positive growth in fungal culture

Result:

Total seven patients met the inclusion criteria. Five out of 7 patients were male. The mean age was 35 years. Five of the 7 patients presented with fever for long duration. Six patients complained of significant weight loss before diagnosis. On examination, one patient had skin nodules, five patients had hepato-splenomegaly, and two patients had lymphadenopathy.

The laboratory investigation revealed anaemia in six out of 7 patients, and pancytopenia in 3 patients. Two patients had features of hemophagocytic syndrome in the bone marrow.

All of the patient had undergone treatment with conventional amphotericine B  deoxy-cholate and azole antifungal. One patient with adrenal involvement died in hospital. The patient with skin nodule had recurrent relapses. The other patients had resolution of symptoms and clinically cured.

Conclusion:

Disseminated Histoplasmosis is not an uncommon etiology of fever of prolonged duration even in immuno-competent individual, and should be kept as a differential diagnosis. Targeted investigation with early bone marrow biopsy and fungal culture may help in diagnosis of DH. Imaging study to exclude adrenal involvement prevents case fatality in DH. Cytopenia may be due to secondary hemophagocytic syndrome, which improves with anti-fungal therapy. Treatment with either amphotericine B or itraconazole gives excellent outcome, though therapy may have to given for prolonged period in case of relapses.