Balamuthia mandrillaris

Background

Microbiology

• One of the free-living amoebae

Epidemiology

• Present in soil
• More common in US and South America
• More common in Hispanics

Clinical Manifestations

• Causes granulomatous amebic encephalitis (GAE) alone, skin lesions followed by GAE, or (rarely) skin lesions alone
  • Characterized by progressive hemorrhagic necrosis of brain, with 90% mortality
  • Fever, headache, altered mentation), vomiting, lethargy, seizures, and weakness
• Often preceded by skin lesions by a few weeks to 2 years
  • Typically affect the nose and cheeks, but also torso and limbs
  • Often a single lesion
  • Progress over months from papulonodular erythematous plate-like areas, enlarging and eventually ulcerating
  • Typically painless
• Can also initially present with rhinitis, sinusitis, or otitis media
• Difficult to treat, with high mortality

Management

• Based on case reports
• Combination therapy recommended by CDC:
  • Pentamidine 4 mg/kg IV once daily
  • Sulfadiazine 1.5 g PO q6h
  • Flucytosine 37.5 mg/kg PO q6h
  • Fluconazole 12 mg/kg PO/IV once daily
  • Azithromycin 20 mg/kg (max 500 mg) PO once daily (or clarithromycin
  • Miltefosine 50 mg PO tid (if ≥45 kg) or bid (if <45 kg)