Histoplasmosis is a fungal lung infection caught by breathing spores from soil mixed with bird or bat droppings, common in the Ohio and Mississippi River valleys. Most healthy people have a mild illness, but a heavy exposure or weak immunity can cause severe or spreading disease.
Key symptoms
- Fever, chills and fatigue
- Dry cough and chest pain
- Headache and muscle aches
- Shortness of breath after a heavy exposure
- Weight loss and night sweats in chronic forms
What you find on exam
- Vital signs and oxygen saturation
- Lung exam, often normal or with mild crackles
- Enlarged liver, spleen or lymph nodes in spread disease
- Skin lesions or mouth ulcers in disseminated disease
Tests
- Exposure, travel and job history (caves, chicken coops, demolition)
- Urine and serum Histoplasma antigen
- Chest X-ray or CT: patchy infiltrates and enlarged hilar lymph nodes
- Fungal antibodies and culture; HIV test if the disease is severe
Treatment basics
- Mild illness often clears without treatment
- Itraconazole for moderate or prolonged illness, usually 6 to 12 weeks
- Liposomal amphotericin B for severe or disseminated disease, then itraconazole
- Check itraconazole blood levels and drug interactions
Red flags
- Low oxygen or respiratory failure
- Signs of spread: low blood pressure, large liver and spleen, low blood counts
- Severe illness in a person with HIV or on immune-suppressing drugs
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.