What is Entamoeba?
Entamoeba is a genus of amoeboid protozoa, which includes several species, some of which are pathogenic to humans. The most notable species is
Entamoeba histolytica, known for causing amoebiasis, an intestinal illness. This organism primarily resides in the lumen of the human intestines but can sometimes invade the intestinal wall and other tissues.
How is Entamoeba identified in histological samples?
In histological samples, Entamoeba can be identified by its morphology. Under the microscope,
trophozoites of Entamoeba histolytica appear as round to oval cells with a size ranging from 15 to 60 micrometers. They have a characteristic nucleus with a central karyosome and fine peripheral chromatin. The presence of ingested red blood cells within the cytoplasm is a distinguishing feature of E. histolytica.
What are the histopathological features of Entamoeba infection?
Histopathologically, Entamoeba infection can present with several features. The most common finding is the presence of
ulcerations in the intestinal mucosa, often described as "flask-shaped" due to their wide base and narrow neck. There can be a significant inflammatory response, with the presence of neutrophils, lymphocytes, and macrophages. In severe cases, the trophozoites can invade the submucosa, muscularis propria, and even the serosa.
What are the complications of Entamoeba infection?
If left untreated, Entamoeba infection can lead to serious complications. The most severe include
amoebic liver abscess, where the trophozoites migrate to the liver, causing necrosis and abscess formation. Other complications include perforation of the intestinal wall, leading to peritonitis, and the spread of the infection to other organs such as the lungs and brain.
How does Entamoeba affect tissue architecture?
Entamoeba histolytica has a direct impact on tissue architecture. The organism produces enzymes such as
cysteine proteases that degrade the extracellular matrix and epithelial cells, leading to tissue destruction. This results in the characteristic ulceration and, in severe cases, extensive tissue necrosis. The inflammatory response further damages the tissue structure, exacerbating the clinical manifestations of the disease.
How is Entamoeba infection diagnosed histologically?
Diagnosis of Entamoeba infection histologically involves identifying the trophozoites in tissue sections. This requires a combination of clinical suspicion and specific histological findings. In addition to direct microscopic examination, ancillary techniques such as
immunohistochemistry and molecular methods like PCR can be employed to confirm the diagnosis.
What is the treatment for Entamoeba infection?
The treatment for Entamoeba infection typically involves the use of
antiparasitic medications such as metronidazole or tinidazole, which are effective against the trophozoites. For asymptomatic carriers, luminal agents like paromomycin or iodoquinol are used to eliminate the cysts. In cases of abscess formation or severe infection, surgical intervention may be necessary.