Although amebic brain abscess is a rare form of invasive amebiasis, when present, it is frequently lethal. This disorder always begins with the infection of the colon by Entamoeba histolytica trophozoites, which then travel to extra-intestinal tissues through the bloodstream. Amebic brain abscesses are produced when trophozoites invade the central nervous system. Computerized axial tomography scans can be used to diagnose the presence or absence of a brain abscess with a certainty of 100%. However, this diagnostic tool does not reveal the etiological agent of disease. By analyzing the clinical case of a patient that died due to untimely treatment of this malady, the present study aims to identify a diagnostic tool that can give a precise determination of the etiological agent and therefore permit adequate and opportune treatment. Currently, diagnosis of amebic brain abscess is often done by identification of the ameba in a biopsy or autopsy. By immunohistochemistry and immunofluorescence with specific antibodies, we identified the existence of E. histolytica, which presents proteins similar to Naegleria fowleri in its membrane.

Background The parasite Entamoeba histolytica is the causal agent of amoebiasis, a worldwide emerging disease. Amebic brain abscess is a form of invasive amebiasis that is both rare and frequently lethal. This condition always begins with the infection of the colon by E. histolytica trophozoites, which subsequently travel through the bloodstream to extraintestinal tissues. Case presentation We report a case of a 71-year-old female who reported an altered state of consciousness, disorientation, sleepiness and memory loss. She had no history of hepatic or intestinal amoebiasis. A preliminary diagnosis of colloidal vesicular phase neurocysticercosis was made based on nuclear magnetic resonance imaging (NMRI). A postsurgery immunofluorescence study was positive for the 140 kDa fibronectin receptor of E. histolytica, although a serum analysis by ELISA was negative for IgG antibodies against this parasite. A specific E. histolytica 128 bp rRNA gene was identified by PCR in biopsy tissue. The final diagnosis was cerebral amoebiasis. The patient underwent neurosurgery to eliminate amoebic abscesses and was then given a regimen of metronidazole, ceftriaxone and dexamethasone for 4 weeks after the neurosurgery. However, a rapid decline in her condition led to death. Conclusions The present case of an individual with a rare form of cerebral amoebiasis highlights the importance of performing immunofluorescence, NMRI and PCR if a patient has brain abscess and a poorly defined diagnosis. Moreover, the administration of corticosteroids to such patients can often lead to a rapid decline in their condition.