Granulomatous amoebic encephalitis

Granulomatous amoebic encephalitis ("GAE")^[1] is a central nervous system disease caused by certain species,^[2] especially species of Acanthamoeba and Balamuthia mandrillaris.^[3][4]

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.^[5][6][7][8]

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 paralysis, 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.

Appearance on Biopsy

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.

Treatment

GAE, in general, must be treated by killing the pathogenic amoebas which cause it.

Acanthamoeba

Even with treatment, the condition is often fatal, and there are very few recorded survivors, almost all of whom suffered permanent neurocognitive deficits. 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).^[9]

Balamuthia

In one case, cloxacillin, ceftriaxone, and amphotericin B were tried.^[10]

References