Ischemic and Vascular GI Flashcards
What artery supplies the small intestines?
Superior Mesenteric Artery
Atrial fibrillation often leads to what?
Development of thrombosis in the atrium which can travel to the SMA and lead to ischemic bowel
Connection between the Celiac artery and the SMA?
Pancrealicoduodenal arcade
Connection between the SMA and IMA
Arc of Riolan
Vasodilators in the GI?
Gastrin, CCK, Secretin
All released during feeding
Vasoconstrictors in teh GI
Catecholamines, Ang II, Vasopressin
How is the GI system affected by hypovolemia
Massive hemorrhage–> reduced blood volume–> decreased venous return to the heart –> Hypotension and low Cardiac Output—> Increased peripheral resistance –> Redistribution of blood flow to vital organs (heart, brain, lungs, kidneys) –> decreased splanchnic blood flow
Which part of the bowel will be injured first in response to low blood flow?
Tops of Villi, the necrosis proceeds downward from there.
Patients will have different symptoms depending on what level the infarction has reached
Know the different levels of infarction
Mucosal, Mural , Transmural
Ischemic colitis presentation
Bleeding but pain level may be low
Diarrhea may be present
In Ischemic Colitis, what area of the small bowel is most sensitive to ulcer development? KNOW
Splenic Flexure or between the sigmoid colon and rectum…Apparently areas where we have connections between the two big vessels
Acute Mesenteric Ischemia is what
First off, its a medical emergency because delaying treatment can lead to bowel necrosis
Clinical presentation of Acute Mesenteric Ischemia is what
Early abdominal pain without Ileus (obstruction)
How do you diagnose Ischemic colitis?
CT and colonscopy
How do you diagnose acute mesenteric ischemia
CT. NO ENDOSCOPY
Angiography is gold standard….injecting contrast in arteries and look on CT
Portal vein gas?
Usually associated with acute mesenteric ischemia…not a good sign because it usually represents complete necrosis of teh bowel wall
Tx of acute mesenteric ischemia
vasodilators via angiography. Surgery is the only possible cure but its very risky and outcome is poor
Dusky Bowel
Bowel Infarct
Know distinguisihng features slide
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Chronic ischemia criteria/cause?
At least two of the three splanchnic arteries usually have serious occlusion
Presentation of Chronic ischemia
Abdominal Pain after eating, they lose a lot of weight because they don’t eat much
Venous mesenteric Ischemia cause
Hyper-coaguable state (often due to an autoimmune disorder which means that women are affected more than men)
Upper GI bleed classified how
Bleeding that comes from above the angle of Trait
Lower GI bleed classified how
Bleeding that comes from below the angle of trait
What the hell is the angle of trait
It is a fibrous ligament that attaches the junctin between the duodenum and jejunum to the diaphragm
Obscure overt bleeding
You can see the blood but you don;t know where its from
Obscure occult bleeding
You cannot see the blood nor do you know where its coming from
What is melena?
Black, tarry, loose or sticky stool caused by degraded blood in the intestine and generally indicates an upper GI source. Smells bad
Hematochezia
Bright red blood from the rectum, lower Gi usually. If it comes from upper GI then you have a massive hemorrhage
Upper Gi bleeding more common in who
men and the elderly
80% of upper GI bleeds are self-limited
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Causes of upper GI bleeds
ulcers gastritis tumors vascular malformation esophagitis
During endoscopy, what finding signifies the highest risk of re-bleeding?
Active bleeding during the procedure
During endoscopy, what finding signifies the second highest risk of re-bleed?
Visualization of a Stigmata ( a visible vessel that looks like it is about to explode)
Low risk of re-bleed
Completely white
What locations in the GI can lead to high risk of re-bleed?
Posterior wall of the duodenal bulb or lesser curve of stomach
Esophageal varices mortality
30-50%
Most common cause of acute lower GI bleed?
Diverticulosis and angiodysplasia
Most common cause of chronic bleed
Hemorrhoids and neoplasia
Angiodysplasia is what
AVM (arteriovenous malformation)
Risk factors for angiodysplasia development?
Chronic lver failure, old age, prior radiation therapy
Angiodysplasia blood loss most commonly where
cecum and right side colon
slow intermittent blood loss= Angiodysplasia
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