Clinical History:
18 year old female patient presents with history of fever over 6 weeks duration,
recently episodes of generalized convulsions.
Discussion:
Entamoeba histolytica is the etiological agent in cerebral amoebiasis.
This is a common organism in the Indian subcontinent. Amoebic involvement
of the liver and gut is endemic in this part of the world, and typically
results in liver abscess and intestinal infection.
CNS infection occurs following hematogenous spread from intestinal disease.
Often, there are coexisting liver abscesses. Men are affected ten times
more frequently than women. The clinical symptoms of CNS involvement are
usually non-specific. Pathologically, there are multiple parenchymal hemorrhagic
lesions characterized by central necrosis which varies in size from 2
— 60 mm.2 Anti-amoebic antigens are usually present in
the serum. CSF examination is usually of no help in establishing the diagnosis.
On imaging, there may be evidence of associated meningitis. The presence
of multiple hemorrhagic ring enhancing lesions is the key to the diagnosis.
The main differential in cases of multiple hemorrhagic ring enhancing
lesions would be toxoplasmosis. Patients with toxoplasmosis are nearly
always immuno-compromised, whereas cerebral amoebiasis occurs in immuno-competent
individuals. From an imaging perspective, hemorrhage is seen in some,
but not all, lesions in toxoplasmosis. In cerebral amoebiasis, all the
lesions reveal hemorrhage in a relatively symmetrical fashion.
These infections are usually fatal, although early treatment with metronidazole
may help to alter the outcome.
Diagnosis:
Cerebral Amoebiasis
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