Encephalitis due to a free-living amoeba (Balamuthia mandrillaris): case report with literature review

Surg Neurol. 2000 Jun;53(6):611-6. doi: 10.1016/s0090-3019(00)00232-9.


Background: Amebic infections can spread to the central nervous system with a lengthy but usually fatal course. A typical case is presented to raise awareness of this increasingly reported infectious process that may have a more favorable outcome if diagnosed in its early stages.

Case description: A 38-year-old male presented with an ulcerating 10 x 8 cm mass on his thigh and smaller skin nodules. In less than 6 months seizures developed due to granulomatous lesions of the brain. Biopsies/excisions of the thigh lesion, a subcutaneous nodule, and a brain lesion were performed. He failed to respond to broad spectrum antibiotics and antineoplastic agents, and died within 6 weeks of the initial MRI scan of the brain. Rare amebic trophozoites were appreciated in the biopsy specimens on post-mortem review, and Balamuthia mandrillaris confirmed as the infecting agent on immunofluorescence studies.

Conclusions: Granulomatous amebic encephalitis is a parasitic infection with a lengthy clinical course before rapid deterioration due to extensive brain lesions is noted. Either early treatment with antimicrobials or-in rare cases-excision of the brain lesion(s) may offer the chance of a cure.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Adult
  • Amebiasis / complications*
  • Amoeba / isolation & purification*
  • Animals
  • Brain / pathology
  • Encephalitis / diagnosis
  • Encephalitis / parasitology*
  • Humans
  • Magnetic Resonance Imaging
  • Male