• Describe the clinical presentation, neuroimaging findings, and diagnostic workup of Granulomatous Amebic Encephalitis and treatment.

Granulomatous Amebic Encephalitis (GAE) is caused by Acanthamoeba species which are microscopic free living amoeba found worldwide in soil, lakes, rivers and tap water. Infections are rare, affecting only 3-12 persons annually in the United States, and 82% of cases are fatal. People with compromised immune systems are at increased risk of fatal cerebral infection from Acanthamoeba species. Infections involving the CNS can occur following exposure to contaminated, warm fresh water, heating, or air-conditioning units. 

Case description:

A 71-year-old caucasian female with a past medical history chronic lymphocytic leukemia (CLL) being treated with chemotherapy presented to the emergency department with seizure-like activity. She developed increasing focal motor activity involving the right upper extremity within the previous two weeks and speech difficulty within two days without loss of consciousness. Imaging from the transferring facility showed multifocal intracranial lesions, largely involving the left frontal lobe with associated vasogenic edema. She was transferred for further evaluation to an academic hospital, with MRI findings including bilateral cerebral enhancing masses with central necrosis and hemorrhaging, along with other findings. Treatment with dexamethasone for the vasogenic cerebral edema and 3% saline for hyponatremia was initiated. An endoscopic sinus surgery with biopsy was performed to evaluate a nasal mass found on exam, followed by frontal open brain biopsy. Biopsies were positive for Acanthamoeba, indicating treatment changes.  

N?A

Acanthamoeba species are free-living amoebae that are ubiquitous in our environment, posing a threat largely to immunocompromised patients like the case reported here with the patient currently on chemotherapy for CLL. Unfortunately, CNS involvement despite appropriate therapy causes rapid deterioration with mainly immunocompetent patients surviving and immunocompromised patients having a more fatal prognosis. This case demonstrates the rapid and severe nature of Acanthamoeba encephalitis.