Vascular GI Diseases (Tombazzi and Nichols) Flashcards Preview

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Flashcards in Vascular GI Diseases (Tombazzi and Nichols) Deck (52)
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1

The main arteries involved in GI vascular support include

celiac trunk, superior mesenteric artery and inferior mesenteric artery

2

What is the most sensitive artery to ischemic events

SMA

3

Superior mesenteric is responsible of giving the vascular support to

pancreatico-duodenal area
small intestine
right colon

4

the SMA terminates as the

ileo-colic artery

5

provides protection from ischemia in setting of segmental vascular occlusion

collateral circualtion

6

accounts for a wide fluctuation in splanchnic blood flow

Changes in the resistance of mesenteric arterioles

7

hormones that cause vasoconstriction of GI arterioles

catecholamines
Ang II
vasopressin
**secreted during shock and heart failure

8

hormones that cause vasodialtion of GI arterioles

gastrin
CCK
secretin
**secreted after mealtime

9

describe the intracellular signal responsible for vasodilation

production of NO

10

describe the intracellular signal responsible for vasoconstriction

activation of PLC --> IP3 --> release of Ca from SR

11

most sensitive part of the GI tract/will die first

top of the villi
**as ischemia persists, necrosis will progress down towards/thru the wall

12

How much of the bowel wall must be infarcted for you to clinically see rebound tenderness

to the serosa = transmural

13

clinically how does a mucosal infarct present?

bleeding

14

How much of the wall must be infarted to clinicallt see ileus?

villi/mucosa must be gone = mural or transmural

15

Causes of acute ishemia involving small bowel

1. embolism from L side of heart to SMA
2. thrombosis of SMA
3. non-occusive ischemia (HF or shock)
4. Mesentreric venous thrombosis (hypercoag state--think autoimmune dz)
5. neoplasm or vasculitis
**Goljian

16

radiographic findings seen with small bowel infarction

thumbprinting = due to edema in lamina propria
bowel distension with air fluid level
**Goljian

17

Common pathogenesis and presentation of ischemic colitis

Pathogen: artherlosclerosis of SMA
Presents: pain and tenderness (at splenic flexure commonly) ,hematochezia

**Diffuse disease of small vessels (diabetes mellitus, vasculitis) can also lead to this

18

Outcome of ischemic colitis

generally benign, but fibrosis can lead to strictures and obstruction

19

What part of the GI tract does ischemic colitis typically invovle

watershed/splenic flexure and rectosigmoid area
(rarely rectum)

20

Presentation of acute mesenteric ischemia

early: abdominal pain, NO ileum
later: rebound tenderness and ileus
**there is NOT always blood

21

What does portal vein gas indicate?

air from lumen of GI is getting into venous system (??? i think thats what he said??) or bacteria colonizing venous system is producing gas

22

term used to describe dead bowel

dusky

23

pseudomembrane and mucin depletion is assc with acute or chonic bowel ischemia

acute

24

hyalinization and withering of crypts is assc with acute or chonic bowel ischemia

chronic

25

gangrenous necrosis, pneumatosis intestinalis and segmental absence of muscularis propria

Neonatal necrotizing enterocolitis (NEC)

26

How is ischemic colitis distinguished from acute mesenteric ischemia

IC: > 60 yo, not an acute cuase, mild pain and tenderness, bleeding

AMI: any age, usually acute, severe pain, tenderness appears late, uncommonly assc with bleeding

27

Hallmark presentation of chronic bowel ishemia

abdominal pain after eating --> weight loss
** 2 of the 3 splanchnic arteries usually have significant occlusive disease

28

most common cause of chronic ischemia

artherlosclerosis

29

time course to presentation of venous mesenteric ischemia relative to arterial

venous takes longer--several days

30

upper vs. lower GI bleed is distinguished as being above or below ...

the ligament of Treitz
**attaches jejunum/duodenum to diaphragm