December 2017
A 15-year-old adolescent girl with a history of type 1 diabetes and celiac disease
Granulomatous Amebic Encephalitis from Balamuthia Mandrillaris
- Background:
- B. mandrillaris CNS infections are very rare and usually fatal. It is a soil ameba that may be acquired from inhalation of cysts or through open wounds with hematogenous spread to the CNS.
- 1100 patients have been reported worldwide as of 2010, with only 6 reported survivors.
- Clinical Presentation:
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Additional history in this case: Well-controlled DM I and celiac disease; swam in freshwater pond 9 months prior to admission; acute hemorrhagic leukoencephalitis was initially suspected given appearance of brain lesions and history of autoimmune disease, prompting onset of steroids; antibiotics were started after progression on MRI and a brain biopsy, but patient died 1 day later
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Patients can present with a wide variety of focal neurologic deficits, altered mental status, headaches, and fever.
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Exposure status is also variable, and there is uncertainty as to whether B. mandrillaris can be waterborne.
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Variability in clinical findings and lack of definitive exposure history mean diagnosis is often delayed.
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- Key Diagnostic Features:
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Multiple focal lesions demonstrating variable degrees of peripheral enhancement, restricted diffusion, and surrounding vasogenic edema.
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Signs of internal hemorrhage are often reported.
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- Differential Diagnoses:
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Demyelinating disease, neoplasm (especially metastatic)
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- Treatment:
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Combination of antimicrobials including miltefosine, fluconazole, and albendazole
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Multiple hemorrhagic cerebral lesions should prompt discussion of amebic infection and possible brain biopsy in the appropriate clinical setting.
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