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| | '''For patient information, click [[Granulomatous amoebic encephalitis (patient information)|here]]''' |
| | {{Granulomatous amoebic encephalitis}} |
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| {{CMG}} | | {{CMG}} |
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| ==Overview== | | ==[[Granulomatous amoebic encephalitis overview|Overview]]== |
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| '''Granulomatous amoebic encephalitis''' is a [[central nervous system]] disease caused by certain species of [[amoeba]], especially ''[[Balamuthia mandrillaris]]''.
| | ==[[Granulomatous amoebic encephalitis pathophysiology|Pathophysiology]]== |
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| ==Pathophysiology== | | ==[[Granulomatous amoebic encephalitis causes|Causes]]== |
| Granulomatous amoebic encephalitis is most commonly caused by Acanthamoeba castellanii, A. culbertsoni, A. polyphaga or [[Balamuthia mandrillaris]].<ref>Martinez AJ, Visvesvara GS, Chandler FW. Free-living amebic infections. Chapter 132 in Pathology of Infectious Diseases, 1997, Connor DH, Chandler FW, Manz HJ, Schwartz DA, Lack EE, eds., Stamford, Appleton & Lange, pp 1163-1176.</ref> It is rarely due to [[Entamoeba histolytica]]. | |
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| [[E. histolytica]] rarely infects the central nervous system and when it does, it tends to cause an abscess with a fulminant clinical course culminating in the patient's death within 12-72 hours (untreated). [[E. histolytica]] infection of the brain also tends to occur in patients with a previous diagnosis of [[E. histolytica]] infection of the intestines, the liver or the lungs. | | ==[[Granulomatous amoebic encephalitis differentiating granulomatous amoebic encephalitis from other diseases|Differentiating amoebic encephalitis from other Diseases]]== |
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| Granulomatous amoebic encephalitis is also rarely due to [[Naegleria fowleri]]. [[N. fowleri]] generally causes acute encephalitis in immunocompetent hosts who go swimming underwater or diving outdoors in fresh water in warm weather. | | ==[[Granulomatous amoebic encephalitis epidemiology and demographics|Epidemiology and Demographics]]== |
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| Chronically ill, debilitated, immunosuppressed or immunodeficient patients tend not to engage in such activities.
| | ==[[Granulomatous amoebic encephalitis risk factors|Risk Factors]]== |
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| | ==[[Granulomatous amoebic encephalitis natural history, complications, and prognosis|Natural History, Complications and Prognosis]]== |
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| ==Diagnosis== | | ==Diagnosis== |
| ===Symptoms===
| | [[Granulomatous amoebic encephalitis history and symptoms|History and Symptoms]] | [[Granulomatous amoebic encephalitis laboratory tests|Laboratory Findings]] | [[Granulomatous amoebic encephalitis CT|CT]] | [[Granulomatous amoebic encephalitis MRI|MRI]] | [[Granulomatous amoebic encephalitis other imaging findings|Other Imaging Findings]] | [[Granulomatous amoebic encephalitis other diagnostic studies|Other Diagnostic Studies]] |
| *[[Headache]]
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| *Low-grade [[fever]]
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| *Mood swings
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| *[[Lethargy]]
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| *[[Confusion]]
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| *[[Seizures]]
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| *Focal neurological deficits (such as [[hemiparesis]] or cranial neuropathy)
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| *Meningeal irritation (such as stiff neck)
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| Symptoms of [[increased intracranial pressure]] such as [[nausea]] and [[vomiting]] are common <ref> Martinez AJ, Visvesvara GS, Chandler FW. Free-living amebic infections. Chapter 132 in Pathology of Infectious Diseases, 1997, Connor DH, Chandler FW, Manz HJ, Schwartz DA, Lack EE, eds., Stamford, Appleton & Lange, pp 1163-1176.</ref> | |
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| ===CT Findings===
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| [[Image:CT showing granulomatous amoebic encephalitis.jpg|CT scan showing granulomatous amoebic encephalitis|left|thumb]]
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| A computerized tomography scan may demonstrate bilateral low-density areas with mild mass effect in the cortex and subcortical white matter as shown here.
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| Magnetic resonance imaging (MRI) scans may show increased signal on T2-weighted images. The lesions may show ring enhancement with intravenous contrast studies. Occasionally, there are neuroradiographic findings of an expanding intracranial mass that may mimic a cerebral tumor or a [[brain abscess]].
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| ===Pathology===
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| [[Image:Septic embolii to the brain 2.jpg|left|thumb]]
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| [[Image:Septic embolii to the brain.jpg|left|thumb]] | |
| [[Image:Septic embolii to the brain 3.jpg|left|thumb]]
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| The amoebae producing granulomatous encephalitis characteristically produce cysts in the infected tissue whereas E. histolytica and N. fowleri do not.
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| Multifocal encephalomalacia, [[edema]], [[necrosis]], hemorrhage and sometimes abscess formation are observed. The meninges may be cloudy. Uncal or cerebellar tonsillar herniation may be present. Lesions occur in the cerebral hemispheres, the basal ganglia, the brainstem and the cerebellum. A necrotizing subacute or chronic granulomatous encephalitis with [[lymphocytes]], [[macrophages]] and [[multinucleated giant cells]], and variable numbers of organisms are observed microscopically. There may be thrombosis of small blood vessels associated with necrosis and hemorrhage. In AIDS patients, the inflammatory reaction is minimal and composed mainly of CD-68 positive [[macrophages]].
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| ==Appearance on Biopsy==
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| [[Image:Microscopic findings in GAE.jpg|left|thumb]]
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| A [[brain biopsy]] will reveal the presence of infection by pathogenic amoebas. In GAE, these present as general inflammation and sparse [[granules]]. On microscopic examination, infiltrates of amoebic [[cysts]] and/or [[trophozoites]] will be visible.
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| ==Cerebrospinal Fluid==
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| The CSF demonstrates a lymphocytic pleocytosis, with mildly elevated protein and normal glucose, but diagnostic organisms are not readily identified. Lumbar puncture is contraindicated if there are signs and symptoms of an increase in [[intracranial pressure]].
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| ==Treatment== | | ==Treatment== |
| GAE can, in general, must be treated by killing the pathogenic amoebas which cause it. Even with treatment, the condition is often fatal, and there are very few recorded survivors, almost all of whom suffered permanent [[neurocognitive|neurocognitive deficits]]. Several drugs have been shown to be effective against GAE-causing organisms ''[[in vitro]]''.<ref>http://path.upmc.edu/cases/case156/dx.html</ref>
| | [[Granulomatous amoebic encephalitis medical therapy|Medical Therapy]] | [[Granulomatous amoebic encephalitis primary prevention|Primary Prevention]] |
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| ==References== | | ==Case Studies== |
| {{Reflist|2}}
| | [[Granulomatous amoebic encephalitis case study one|Case #1]] |
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| ==External links== | | ==External Links== |
| * {{cite journal |author=Intalapaporn P, Suankratay C, Shuangshoti S, Phantumchinda K, Keelawat S, Wilde H |title=Balamuthia mandrillaris meningoencephalitis: the first case in southeast Asia |journal=Am. J. Trop. Med. Hyg. |volume=70 |issue=6 |pages=666-9 |year=2004 |pmid=15211011 |url=http://www.ajtmh.org/cgi/content/full/70/6/666}}
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| | http://www.cdc.gov/parasites/balamuthia/epi.html |
| | [[Category:Disease]] |
| [[Category:Neurology]] | | [[Category:Neurology]] |
| [[Category:Infectious disease]]
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