Blastomycosis

Background

• Fungus: Blastomyces dermatitidis
• Lives in moist soil, wooded areas
• Spores airborne
• Incubation: 3-6 weeks
• North, Central and South America
• Southeast and Midwest US (Mississippi and Ohio River valleys)
• Reportable disease
• Systemic pyogranulomatous infection

Clinical Features

• Flu like symptoms: Fever, chills, cough, muscle aches, joint pain, chest pain
• Up to 50% asymptomatic
• Systemic: Weight loss, night sweats, chills
• Pulmonary: most common
  • Acute or chronic pneumonia
  • Diffuse pneumonitis, ARDS
• Skin:
  • Verrucous lesion with irregular borders
  • Microabscess (cold), subcutaneous nodules
  • Ulcers that bleed easily and well-demarcated
• Bone: Osteomyelitis, chronic draining sinus, paravertebral abscess
• Genitourinary: Prostatitis, epididymoorchitis
• CNS: Meningitis, epidural/intracranial abscess in immunocompromised
• Can involve breast, adrenal, thyroid, eye, lymph node, liver, spleen

Differential Diagnosis

• Pneumonia
• Malignancy
• Tuberculosis
• Histoplasmosis
• Pyoderma gangrenosum
• Keratoacanthoma

Workup

• Fungal culture (Blood, sputum, bone marrow, liver or skin) : Broad based buds
• Antigen test (Serum or urine)
• Histopathology
• Serologic testing
• HIV testing
• CXR: Alveolar infiltrates +/- cavitation, mass lesions, miliary or reticulo- or fibronodular pattern, pleural effusions, upper lobe infiltrat
• Chest CT: Nodules, consolidation +/- cavitation, tree-in-bud opacities, pleural effusion, lack hilar adenopathy
• Xray of bone: Well-circumscribed osteolytic lesion
  • Xray vertebrae: Lytic lesion in anterior vertebral body and destruction of disc space
• Bronchoscopy

Management

• ID consult
• Mild or moderate infections: Itraconazole (200mg TID x 3 days then once or twice daily x 6-12 months)
  • Alternative: Fluconazole or ketoconozale (400-800mg/day)
  • Azoles embryotoxic and teratogenic, avoid in pregnancy
• Severe infection: Amphotericin B (Lipid 3-5mg/kg IV daily or deoxycholate 0.7-1mg/kg IV daily)
  • All immunocompromised patient should receive amphotericin B
  • Lipid for all patients, except children
  • If CNS involvement, lipid for all patients

Disposition

• Subclinical disease: Observation and no treatment
• Patients with immunocompetence or progressive pulmonary or extrapulmonary symptoms need treatment and often admission
• Some may need ICU

External Links

• http://www.idsociety.org/uploadedFiles/IDSA/Guidelines-Patient_Care/PDF_Library/Blastomycosis.pdf

Sources

• http://www.cdc.gov/fungal/diseases/blastomycosis/information.html
  • Bradsher RW, et al. Clinical manifestations and diagnosis of blastomycosis. In: Post T, ed. UpToDate. Waltham, Mass.: UpToDate; 2014. www.uptodate.com. Accessed December 43, 2014.
  • Chapman SW, et al. Clinical practice guidelines for the management of blastomycosis: 2008 update by the Infectious Diseases Society of America. CID. 2008; 40: 1801-1812.
  • Bradsher RW, et al. Treatment of blastomycosis. In: Post T, ed. UpToDate. Waltham, Mass.: UpToDate; 2014. www.uptodate.com. Accessed December 24, 2014.
  • Varkey B, et al. (2014, Jun 30).Blastomycosis. eMedicine. Retrieved 12/24/2014 from http://emedicine.medscape.com/article/296870-overview