Blastomycosis is a fungal infection caused by Blastomyces, which lives in moist soil and decaying wood near rivers and lakes in the Ohio and Mississippi River valleys and the Great Lakes area. Breathing in spores causes a lung infection that can spread to the skin, bones and genitourinary tract.
Key symptoms
- Cough, fever, chest pain and fatigue, like a pneumonia that does not improve with antibiotics
- Weight loss and night sweats in chronic disease
- Skin lesions: wart-like plaques or ulcers with raised borders
- Bone pain or urinary symptoms when it spreads
- Outdoor activity near water or woods in endemic regions
What you find on exam
- Lung findings: crackles or reduced breath sounds
- Wart-like or ulcerated skin lesions, often on the face and limbs
- Tender bone or joint swelling
- Prostate tenderness in men
Tests
- Chest X-ray or CT: consolidation, masses or nodules
- Sputum or tissue culture and microscopy: large yeast with broad-based buds
- Urine antigen test (can cross-react with histoplasmosis)
- Biopsy of skin lesions
Treatment basics
- Mild to moderate disease: itraconazole for 6 to 12 months
- Severe disease or weak immunity: liposomal amphotericin B first, then itraconazole
- Central nervous system disease: amphotericin B, then voriconazole or another azole
- Check itraconazole blood levels and drug interactions
- Ventilator support in respiratory failure
Red flags
- Respiratory failure or ARDS
- Headache, confusion or seizures: spread to the brain
- Disseminated disease in an immunocompromised or pregnant patient
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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.