Potentially life-threatening emergency
Free-living amoeba infection
Alerts and Notices
Synopsis
Patients present with symptoms usually associated with acute bacterial meningitis including fever, headache, mental status changes, and seizures. Analysis of the cerebral spinal fluid (CSF) reveals a high white blood cell count, low glucose, and high protein (as is commonly seen in bacterial meningitis). If a CSF wet mount is performed, trophozoites can occasionally be identified. Infection with Acanthamoeba species or B. mandrillaris can present in a subacute manner with focal neurological deficits. Patients may also have changes in their mental status. These deficits are due to mass lesions in the CNS. Infections with these pathogens are also frequently fatal.
In addition to disease of the CNS, infection with Acanthamoeba species and B. mandrillaris has been reported to occasionally involve other body sites including the sinuses, lungs, and skin. Additionally, Acanthamoeba species can cause a keratitis. Optimal therapy for these severe infections has not been established.
Codes
ICD10CM:B60.2 – Naegleriasis
SNOMEDCT:
266169003 – Free-Living Amoeba Infection
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Diagnostic Pearls
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Differential Diagnosis & Pitfalls
- Bacterial meningitis – fever, headache, mental status changes, and seizures
- Acanthamoeba species or B. mandrillaris can present in a subacute manner with focal neurological deficits. Many other entities could present in a similar manner, including ischemic stroke or entities that present as a CNS mass lesion such as infection (bacterial brain abscess, CNS toxoplasmosis) or malignancy. In some cases, diagnosis of a mass lesion may require biopsy.
- Other causes of keratitis, including keratitis due to bacteria or to herpes simplex virus, could be mistaken for Acanthamoeba keratitis.
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Therapy
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References
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Last Reviewed:11/29/2016
Last Updated:01/12/2017
Last Updated:01/12/2017