amoebic meningoencephalitis

Etiology

• Acanthamoeba* (immunosuppressed hosts)
• Naegleria fowleri* (may occur in immunocompetent hosts)
• Balamuthia mandrillaris
• Sappinia pedata

* most common in U.S.

Epidemiology

• fresh water exposure, including Neti pot

Clinical manifestations

• rapidly progressive meningoencephalitis
• brain edema
• intracerebral hemorrhage
• death within days

Laboratory

• CSF analysis:
  • diminished glucose
  • elevated CSF leukocytes, may be lymphocyte predominant
• brain biopsy
  • foci of necrosis
  • numerous free-floating amoebas, some encysted
  • amoebas may cluster around blood vessels
  • multinucleated giant cells may be seen
• Acanthamoeba antibody in CSF
• Naegleria fowleri antibody in CSF
• Acanthamoeba DNA
• Naegleria fowleri DNA
• Balamuthia mandrillaris DNA

Radiology

• neuroimaging (brain CT or brain MRI)
  • cerebral edema, intracerebral hemorrhage

Management

Acanthamoeba

• trimethoprim-sulfamethoxazole in combination with rifampin & ketoconazole
• combination therapy with fluconazole plus sulfadiazine & pyrimethamine
• miltefosine is used as part of combination therapy
• surgical resection of lesions, when possible

More general terms

• meningoencephalitis
• amebiasis