Histoplasmosis - disseminated

Definition

Disseminated histoplasmosis is an infection caused by inhaling the spores of the fungus Histoplasma capsulatum. This spore is found in moist soil areas along river valleys, such as the Mississippi and Ohio River Valleys.

Alternative Names

Causes

Histoplasmosis is caused by a fungus found in the central and eastern U.S. Mississippi and Ohio River Valley, eastern Canada, Mexico, Central America, South America, Africa, and Southeast Asia.

Most cases are mild or without symptoms. Acute pulmonary histoplasmosis may occur in epidemics. Progressive or spreading (disseminated) and chronic disease can also occur. In disseminated disease, the infection has spread to other organs from the lungs through the bloodstream.

The liver and spleen are usually enlarged, and all body organs may be involved. Ulcerations of the mouth or gastrointestinal tract may occur. Risk factors are travel to or residence within the central or eastern U.S., and exposure to the droppings of birds and bats.

Symptoms

• Fever
• Chills
• Muscle aches and stiffness
• Cough
• Possible rash (erythema nodosum)
• Joint pain
• Skin lesions
• Headache
• Visual changes (chorioretinitis)
• Nausea, vomiting
• Mental status changes

Exams and Tests

A physical examination may show abnormalities throughout the body.

Tests used in the diagnosis of disseminated histoplasmosis may include:

• Complete blood count (CBC)
• Blood cultures
• Biopsy or culture of affected organs, bone marrow, liver, lymph node, lung, or skin
• Abdominal CT scan
• MRI scan of the affected organs
• Abdominal ultrasound
• 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, voriconazole, or fluconazole used for at least 12 months may be effective. AIDS patients should receive long-term oral antifungal therapy (itraconazole is preferred) following initial treatment with amphotericin B.

Outlook (Prognosis)

The disease may progress rapidly and death can occur.

Possible Complications

Multiple organs are affected.

When to Contact a Medical Professional

Call your health care provider if you develop symptoms of disseminated histoplasmosis, 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 may not be practical. Avoid bird or bat droppings if you are in one of these areas, especially if you are immunosuppressed.

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