[Brain Amoebiasis]

Amoebic infections of the brain can cause brain abscesses and meningoencephalitis. Brain abscess is a rare form of extraintestinal amoebiasis caused by hematogenous spread from intestinal infection with Entamoeba histolytica, which occurs through oral intake of contaminated water and food or fecal-oral transmission. It is mostly associated with amoebic liver abscesses and can be effectively treated with metronidazole. Meningoencephalitis caused by pathogenic free-living amoebae is extremely rare. Primary amoebic meningoencephalitis (PAM), caused by Naegleria fowleri infection of the olfactory epithelium with direct intracranial spread via the fila olfactoriae, primarily affects healthy young individuals through exposure to freshwater or brackish water in swimming pools, rivers, ponds, lakes, and estuaries. Granulomatous amoebic meningoencephalitis (GAM) results from the hematogenous spread of extracranial infectious foci caused by Acanthamoeba species or Balamuthia mandrillaris. Acanthamoeba-related GAM is more common in immunocompromised individuals, and waterborne transmission is relatively frequent. Balamuthia mandrillaris-related GAM can affect both immunocompromised and immunocompetent individuals, often affecting people in their 50s to 70s with underlying conditions, such as malignancies, diabetes, and chronic kidney disease, with soil-borne transmission being more common. Both PAM and GAM have high mortality rates, and effective treatments are yet to be established.