Entamoeba Histloytica Flashcards
Clinically to denote all conditions produced in human host
by infection with E. histolytica at different areas of invasion.
Amoebiasis
2 types of amoebiasis (complications)
(1) intestinal and (2) extraintestinal amoebiasis.
Intestinal amoebiasis is clinically classified into:
(a) asymptomatic, and (b) symptomatic infections.
Majority of infections with E. histolytica - occurs in approximately 90% of cases especially in
endemic communities.
Asymptomatic infection
There is NO evidence of tissue invasion.
Asymptomatic infection
Only about 10% of amoebiasis - exhibiting symptoms occurs when the mucosa is invaded.
Symptomatic infections
Other name for Acute amoebic colitis
Amoebic dysentery
Characterized by
gradual or sudden onset, with 6-10 or more blood-tinged, mucoid, foul-smelling stools per day.
Acute amoebic colitis or amoebic dysentery
May resemble bacillary dysentery, but can be differentiated on
clinical and laboratory grounds.
Acute amoebic colitis or amoebic dysentery
Uncommon (only if
rectum is involved), low-grade fever or none at all, and mild leukocytosis.
Tenesmus
Characterized by intermittent diarrhea and constipation. i.e.,
alternating diarrhea and constipation, or abdominal pain.
Chronic amoebic colitis, aka nondysenteric amoebic colitis.
A process wherein proteins, bind to specific carbohydrate-containing receptors on host luminal surfaces and mediate adherence.
Cytoadherence
A group of proteins,
bind to specific carbohydrate-containing receptors on host luminal surfaces and mediate adherence.
Trophozoite lectins
A process wherein E. Histolytica is capable of inserting into the host cell membrane and form pores causing lysis of the host cells.
Cytolysis
Proteins of amoeba
capable of inserting into the host cell membrane and form pores causing lysis of the host cells.
Amoebapores
Process where enzymes are used for further tissue lysis.
Proteolysis
Enzymes that are responsible for further tissue lysis.
Cysteine proteinase enzymes
More often, the trophozoites penetrate to
submucosal layer and multiplies rapidly,
and spread by lateral and downward extension producing a typical
Flask- shaped (or tear drop-shaped) ulcer
The ulcers may involve
the muscular and serous coats of the colon, causing perforation and peritonitis.
Colonic perforation
Occurs in about 60% of fulminant cases.
Blood vessel erosion may cause hemorrhage.
Colonic perforation.
A granulomatous mass may develop
on the intestinal wall.
It is the result of cellular responses to a chronic ulcer and often still contains active trophozoites, usually
in the cecum or rectosigmoid.
Amoeboma
It produces wall thickening and or constriction of the lumen, the so-called ~
“napkin ring” lesion
This may be mistaken for colon cancer.
Amoeboma
Result of trophozoites entering portal circulation or by direct
extension from the intestinal tissues and becoming lodged in the
liver, and other extraintestinal organs such as the lungs, brain,
spleen and cutaneous sites.
Extraintestinal amoebiasis.
