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Category:Intestine - Vascular Disturbances (view source)
Revision as of 13:05, 1 June 2010
, 13:05, 1 June 2010Created page with ' * Vascular disturbances cause obstruction of efferent veins, blockage of afferent arteries or reduced blood flow through unobstructed circulation. ** All have similar effects on…'
* Vascular disturbances cause obstruction of efferent veins, blockage of afferent arteries or reduced blood flow through unobstructed circulation.
** All have similar effects on the intestine
'''Effects of Intestinal Hypoxia'''
* Intestinal hypoxia is induced by vasular distrubances (above).
* '''Timescale:'''
** 10 – 30 minutes - separation of epithelium from basement membrane.
** 1 - 2 hours - villus destruction.
** 2 hours - necrosis of crypt cells.
** 4 - 5 hours - all mucosa necrotic, sloughed.
== Venous Congestion ==
* Commonest cause of intestinal hypoxia
* Usually due to strangulating lesions including intestinal displacements, intussusception etc.
===Pathology===
====Gross====
* Intense oedema
* Congestion
* Haemorrhage
* Eventually dark red/black discolouration of intestine.
====Histological====
* Transmural oedema, haemorrhage and necrosis.
== Arterial thromboembolism ==
* Non-strangulation infarction.
* There is often a functional obstruction at point of infarction.
* Relatively rare as the bowel has a good anastomosing blood supply.
[[Image:strongylus vulgaris.jpg|thumb|right|150px|Thrombosis of cranial mesenteric artery caused by Strongylus vulgaris larvae (Courtesy of Bristol BioMed Image Archive)]]
===Horses===
* E.g. [[Strongylus vulgaris|'''''Strongylus vulgaris''''']] larvae migrating in cranial mesenteric artery in horse
** Cause arteritis with thickening of wall
*** Due to fibrin and debris deposition and hypersensitivity reaction
** Leads to vasoconstriction
*** May occlude lumen and encourage thromboemboli.
** Can cause ischaemic necrosis of a segment of [[Small Intestine - Anatomy & Physiology|small intestine]]
** Is less common now that [[Strongylus vulgaris|'''''Strongylus vulgaris''''']] infections are declining.
* E.g. '''equine''' [[Intestines Fibrinous/Haemorrhagic Enteritis - Pathology#Salmonellosis|'''salmonellosis''']].
[[Image:Infaction of the small bowel.jpg|thumb|right|150px|Infarction of the small bowel (Courtesy of Bristol BioMed Image Archive)]]
===Small Animals===
* Especially dogs
* '''Road traffic accidents''' produce and infact in the gut.
* '''Renal disease''' also causes infarction.
** Particularly nephrotic syndrome.
** Anticoagulant proteins are lost in the urine, leading to a prothrombic state in the ciruclation.
===Pathology===
* Similar to that caused by venous congestion.
* See sharply delineated dark areas in bowel that are flaccid with loss of tone.
** These become necrotic followed later by peritonitis.
[[Category:Intestines,_Small_and_Large_-_Pathology]]