Histoplasmosis is a fungal infection caught by breathing in Histoplasma spores from soil rich in bird or bat droppings, common in the Ohio and Mississippi River valleys. Most infections are silent or mild, but large exposures and weak immunity can cause severe lung or disseminated disease.
Key symptoms
- Fever, chills and headache
- Dry cough and chest pain
- Fatigue lasting weeks
- Weight loss and night sweats in chronic or disseminated disease
- Mouth sores in disseminated disease
What you find on exam
- Lungs often clear, sometimes crackles
- Enlarged liver, spleen or lymph nodes
- Painful mouth ulcers
- Tender red nodules on the shins
- Ask about caves, chicken coops, demolition and travel
Tests
- Histoplasma antigen in urine and serum
- Chest X-ray or CT: patchy infiltrates, hilar nodes, nodules or cavities
- Blood count and liver tests: low counts suggest dissemination
- Antibody tests; culture or pathology from bronchoscopy or bone marrow
Treatment basics
- Mild acute illness usually clears without treatment
- Itraconazole for 6 to 12 weeks if symptoms last over a month or are moderate
- Liposomal amphotericin B for severe or disseminated disease, then itraconazole
- Check itraconazole blood levels
- Long courses for chronic cavitary disease
Red flags
- Low oxygen or breathing distress
- Fever, weight loss and low blood counts in weak immunity
- Confusion or severe headache
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations. Written by Making Synapses. Making Synapses is not affiliated with these organizations.