Histoplasmosis Flashcards
What are the two main types of histoplasmosis and their organisms?
Classical histoplasmosis - Histoplasma capsulatum var. capsulatum
African histoplasmosis - Histoplasma capsulatum var. duboisii
How is classical histoplasmosis usually acquired? Which groups are at risk
Classical histoplasmosis
* Usually found it bat and bird excreta
* Cavers explorers in endemic areas are at particular risk
What are the various clinical presentations of classical histoplasmosis?
Classical histoplasmosis
* Asymptomatic
* Acute pulmonary histoplasmosis
* Chronic pulmonary histoplasmosis
* Acute disseminated histoplasmosis
* Chronic disseminated histoplasmosis
* Atypical presentations
What are clinical clues to classical histoplasmosis disease?
Classical histoplasmosis
* At risk group like caver or person with HIV
* Chronic pulmonary disease can mimic TB with cavitation, cough, haemoptysis
* Disseminated disease has oral ulceration
* Erythema nodosum or erythema multiforme
What are clinical features of acute disseminated histoplasmosis infection?
Acute disseminated histoplasmosis
* Bone marrow suppression
* Hepatosplenomegaly
* Lymphadenopathy
* Umbilicated skin lesions (can resemble cutaneous cryptococcis or talaromycosis but presence of oral ulceration can help differentiate)
* Oral ulceration
* Weight loss
* Fever
Usually in a patient with advanced HIV
How is histoplasmosis infection diagnosed?
- Culture
- Serology or antigen detection
- Giemsa- or Wright-stained visualization of fungus
Stain
* Budding yeast forms within histiocytes
* Halo due to retraction from cell wall
What is the treatment for classical histoplasmosis?
- Mild disease or asymptomatic do not require treatment
- Treatment reserved for severe cases
- Induction with Amphotericin B for severe disease followed by Itraconozole maintenance therapy
- Patients with advanced HIV may require itraconazole for life
