Chapter17: INTESTINES: Angiodysplasia Flashcards
What is Angiodysplasia?
is characterized by malformed submucosal and mucosal blood vessels.
Where does Angiodysplasia occurs
most often?
It in the cecum or right colon, usually after the sixth decade of life.
Although the
prevalence of angiodysplasia is less than 1% in the adult population, it accounts for 20% of
major episodes of lower intestinal bleeding;
intestinal hemorrhage may be chronic and
intermittent or acute and massive.
What is The pathogenesis of angiodysplasia?
remains undefined but has been attributed to mechanical and congenital factors.
Normal distention and contraction may intermittently occlude the submucosal veins that penetrate through the muscularis propria and can lead to focal dilation
and tortuosity of overlying submucosal and mucosal vessels
. Because the cecum has the
largest diameter of any colonic segment, it develops the greatest wall tension.
This may explain
the preferential distribution of angiodysplastic lesions in the cecum and right colon.
Degenerative vascular changes related to aging may also have some role.
Finally, some data
link angiodysplasia with aortic stenosis and Meckel diverticulum, suggesting the possibility of a
developmental component.
What explains the reason of preferential distribution of angiodysplastic lesions in the cecum and right colon.
. Because the cecum has the
largest diameter of any colonic segment, it develops the greatest wall tension.
Degenerative vascular changes related to aging may also have some role.
Finally, some data
link angiodysplasia with aortic stenosis and Meckel diverticulum, suggesting the possibility of a
developmental component.
What is the apperance of the angiodysplasia lesion?
are ectatic nests of tortuous veins, venules, and capillaries.
The vascular channels may be separated from the intestinal lumen by only the vascular wall and a layer of attenuated epithelial cells; limited injury may therefore result in significant hemorrhage
