Master Histoplasmosis with Picmonic for Medicine

Histoplasma is a genus of dimorphic fungi known to be the causative agent of histoplasmosis. This organism has a yeast form that is 2-5 um and found within macrophages within the body. It is commonly found in bat and Starling bird feces and contracted by inhalation of the spores. Therefore, it is commonly associated with entrance into caves and is most prevalent in the Ohio and Mississippi river valleys. Symptoms of this infection vary but the disease primarily affects the lungs, causing pneumonia. Occasionally, the organism can disseminate and affect other organs including the meninges, liver, or adrenals and widely disseminated disease can occur in the immunocompromised. Histoplasma infections produce granulomas, which usually undergo caseation necrosis and can form large areas of consolidation. Like most systemic mycoses, treatment includes an azole antifungal for local infection along with amphotericin B for systemic infection.