Granulomatous amoebic encephalitis
Encyclopedia
Granulomatous amoebic encephalitis ("GAE") is a central nervous system
disease caused by certain species, especially species of Acanthamoeba
and Balamuthia mandrillaris
.
The term is most commonly used with Acanthamoeba. In more modern referendes, the term "Balamuthia amoebic encephalitis" (BAE) is commonly used when Balamuthia mandrillaris is the cause.
, seizures, brainstem symptoms, and other neurological problems, some of which may mimic glioma
(especially brainstem glioma), or other brain diseases, which may hamper timely diagnosis. These symptoms are caused by inflammatory necrosis
of brain tissue brought on by amoebic infiltrates.
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.
. Several drugs (including ketoconazole
, miconazole
, 5-flucytosine and pentamidine
) have been shown to be effective against GAE-causing organisms in vitro
(in a lab petri dish, for example).
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
disease caused by certain species, especially species of Acanthamoeba
Acanthamoeba
Acanthamoeba is a genus of amoebae, one of the most common protozoa in soil, and also frequently found in fresh water and other habitats. The cells are small, usually 15 to 35 μm in length and oval to triangular in shape when moving. The pseudopods form a clear hemispherical lobe at the anterior,...
and Balamuthia mandrillaris
Balamuthia mandrillaris
Balamuthia mandrillaris is a free-living leptomyxid amoeba which is known to cause amoebiasis in humans, especially the deadly neurological condition known as granulomatous amoebic encephalitis . Balamuthia has not been definitively isolated in nature, but it is believed to be distributed...
.
The term is most commonly used with Acanthamoeba. In more modern referendes, the term "Balamuthia amoebic encephalitis" (BAE) is commonly used when Balamuthia mandrillaris is the cause.
Pathology
GAE may present in numerous ways. There is no solid definition, as only a handful of patients have presented thus far with GAE. GAE can present with: focal paralysisParalysis
Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling in the affected area if there is sensory damage as well as motor. A study conducted by the Christopher & Dana Reeve Foundation, suggests that about 1 in 50 people have been diagnosed...
, seizures, brainstem symptoms, and other neurological problems, some of which may mimic glioma
Glioma
A glioma is a type of tumor that starts in the brain or spine. It is called a glioma because it arises from glial cells. The most common site of gliomas is the brain.-By type of cell:...
(especially brainstem glioma), or other brain diseases, which may hamper timely diagnosis. These symptoms are caused by inflammatory necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
of brain tissue brought on by amoebic infiltrates.
Appearance on Biopsy
A brain biopsyBrain biopsy
Brain biopsy is the removal of a small piece of brain tissue for the diagnosis of abnormalities of the brain. It is used to diagnose Alzheimer's disease, tumors, infection, inflammation, and other brain disorders....
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.
Acanthamoeba
Even with treatment, the condition is often fatal, and there are very few recorded survivors, almost all of whom suffered permanent neurocognitive deficitsNeurocognitive
Neurocognitive is a term used to describe cognitive functions closely linked to the function of particular areas, neural pathways, or cortical networks in the brain substrate layers of neurological matrix at the cellular molecular level...
. Several drugs (including ketoconazole
Ketoconazole
Ketoconazole is a synthetic antifungal drug used to prevent and treat fungal skin infections, especially in immunocompromised patients such as those with AIDS or those on chemotherapy. Ketoconazole is sold commercially as an anti-dandruff shampoo, topical cream, and oral tablet.Ketoconazole is...
, miconazole
Miconazole
Miconazole is an imidazole antifungal agent, developed by Janssen Pharmaceutica, commonly applied topically to the skin or to mucus membranes to cure fungal infections. It works by inhibiting the synthesis of ergosterol, a critical component of fungal cell membranes...
, 5-flucytosine and pentamidine
Pentamidine
Pentamidine is an antimicrobial medication given for prevention and treatment of Pneumocystis pneumonia caused by Pneumocystis jirovecii , a severe interstitial type of pneumonia often seen in patients with HIV infection...
) have been shown to be effective against GAE-causing organisms in vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
(in a lab petri dish, for example).