POTD: Blastomycosis

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What's the deal with blasto?


Blastomycosis

  • Infection comes from inhalation of Blastomyces dermatitis or Blastomyces gilchristii

  • Endemic to soil in Great Lakes, Ohio, Mississippi and Saint Lawrence River valleys

  • And now emerging in upstate New York!

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Infection

  • May be asymptomatic, flu-like illness, to respiratory failure and death

  • Lung (91%)

    • Symptoms: cough, fever, sputum production, chest pain, shortness of breath, weight loss, night sweats, chills, hemoptysis

    • Can present as acute or chronic pneumonia that does not respond to treatment

    • May lead to ARDS

  • Extrapulmonary disease

    • Skin (18%) - gray to violet verrucous lesions with irregular boarders

      • may be mistaken for pyoderma gangrenosum or squamous cell carcinoma

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Diagnosis

  • Urine and serum antigens (urine more sensitive), high cross reactivity with histoplasmosis

  • Histologic visualization of yeast on sputum, tissue, or purulence sample

  • Culture (sputum cultures often contaminated with bacteria that will inhibit growth so should also be cultured on medium with chloramphenicol)

  • CT - nodules, consolidation w/ or w/out cavitation, tree-in-bud opacities, LACK of significant hilarity adenopathy (distinguishes it from histoplasmosis)

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Treatment

  • Severe: Amphotericin B 3-5mg/kg daily for 1-2 weeks until improvement noted, then Itraconazole 200mg TID x 3 days then BID for 6-12 months

  • Moderate to mild: Itraconazole 200mg TID x 3 days then BID or QD for 6-12 months

    • Can use fluconazole or ketoconazole but less effective

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