II. Etiology

  1. Blastomyces dermatidis

III. Pathophysiology

  1. Transmitted by exposure to contaminated soil or decomposing timber
    1. Inhalation of spores
    2. Traumatized, non-intact skin exposure (see Cutaneous Blastomycosis)
  2. Endemic regions of United States
    1. Ohio River Basin
    2. Mississippi River Basin
    3. Great Lakes
    4. St. Lawrence River

IV. Symptoms

  1. Pulmonary involvement is initially asymptomatic in 50% of cases
  2. Fever
  3. Sweating
  4. Cough
  5. Nocturnal Joint Pain

V. Signs

  1. Acute disease
    1. See Cutaneous Blastomycosis
    2. Self-limited Pneumonia may clear spontaneously in most patients
  2. Disseminated blastomyces lesions (severe cases may be fatal)
    1. Bone
    2. Nervous system
    3. Lungs
    4. Liver
    5. Spleen
    6. Kidney

VI. Imaging: Chest XRay of Chronic Blastomycosis

  1. Test Sensitivity: 66%
  2. Osteolytic lesions

VII. Lab

  1. Microscopy
    1. Broad-based budding
  2. Skin lesion Evaluation
    1. Pustular discharge for Potassium Hydroxide
    2. Skin biopsy
    3. See Cutaneous Blastomycosis
  3. Systemic disease
    1. Bone Marrow Aspirate
    2. Sputum

VIII. Management

  1. Progressive, refractory, or severe disease or Central Nervous System involvement
    1. Amphotericin B 0.5-0.6 mg/kg daily (MAX 2.0 - 2.5g)
  2. Indolent disease
    1. Adults: Itraconazole 200 mg orally daily for 6 months
    2. Children and Pregnant women: Amphotericin B at dosing above

IX. Course

  1. Incubation: 30-45 days

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