An infection involving many areas of the body. This is caused by inhaling the spores of the fungus Histoplasma capsulatum, which is found in moist soil areas common along river valleys, such as the Mississippi and Ohio River Valleys.
Causes, incidence, and risk factors
Histoplasmosis is caused by a fungus found in the central and eastern United States (Mississippi and Ohio River Valley), eastern Canada, Mexico, Central America, South America, Africa, and Southeast Asia. Most cases are mild or asymptomatic . Acute pulmonary histoplasmosis may occur in epidemics. Progressive or spreading (disseminated) and chronic disease can also occur. In disseminated disease, the infection is spread to other organs of the body from the lungs via the bloodstream. The liver and spleen are usually enlarged, and all body organs can be involved. Ulcerations of the mouth or gastrointestinal tract may occur. Risk factors are travel to or residence within the central or eastern United States, and exposure to the droppings of birds and bats.
Signs and tests
A physical examination may show abnormalities throughout the body. Tests used in the diagnosis of disseminated histoplasmosis may include:
a CBC
blood cultures a biopsy or culture of affected organ(s), bone marrow, liver, lymph node, open lung, skin
an abdominal CT scan
a MRI scan of the affected organ(s)
an abdominal ultrasound
a chest X-ray
a histoplasma urinary antigen test
Treatment
Antifungal medications are prescribed to control the infection. Amphotericin B is the drug of choice. In non-AIDS patients with milder disease, ketoconazole, itraconazole, or fluconazole used for at least 12 months can be effective. AIDS patients should receive chronic oral antifungal therapy (itraconazole is preferred) following initial treatment with amphotericin B.
Expectations (prognosis)
The disease may progress rapidly and death can occur.
Complications
Multiple organs are affected.
Calling your health care provider
Call your health care provider if symptoms of disseminated histoplasmosis develop, particularly if you have been recently treated for acute or chronic histoplasmosis. Emergency symptoms include mental status changes and rapid worsening of the condition of the affected person.
Prevention
Avoiding travel to areas where this spore is found would prevent it (but this is not practical). Avoid bird or bat droppings if you are in one of these areas, especially if you are immunosuppressed .