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Flashcards in Ischemic Bowel Disease Deck (49)
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1

What are the patterns of Ischemic Bowel Disease?

Small and/or large bowel
Diffuse or localized
Segmental or focal
Superficial or transmural

2

4 Main Causes of Acute Mesenteric Ischemia

SMA embolism (50%)
SMA thrombosis (15-25%)
Non-occlusive ischemia (20-30%)
Mesenteric venous thrombosis (5%)

3

How much cardiac output does the intestine take?

10-35%

4

Regulation of Intestinal Circulation

Perfusion pressure
Neural & hormonal mechanisms
Sympathetic nervous system
Renin-angiotensis system
Vasopressin

5

Activity of Vasopressin

Causes mesenteric arterial vasoconstriction & venous dilation
Reduces portal venous pressure in patients bleeding with portal HTN

6

Hallmarks of Clinical Presentation of Ischemic Bowel Disease

Severe, cramping abdominal pain
Pain out of proportion to physical findings
Poorly localized
May be able to hear bruits

7

Clinical Presentation as Ischemia Worsens

Abdominal distention
Absent bowel sounds
Peritoneal signs
+/- feculant odor to the breath
N/V
Frequent BM
Occult blood in stool

8

Occlusive Clinical Syndromes

Mesenteric arterial embolism
Mesenteric arterial thrombosis
Mesenteric venous thrombosis

9

Non-occulusive Clinical Syndromes

Hypoperfusion

10

Risk Factors with Acute Mesenteric ARTERIAL Embolism

Advanced age
CAD
Cardiac valvular disease
Hx of dysrhythmias
Post-mycardial infarction mural thrombi
Hx of thromboembolic disease
Aortic surgery
Aortography
Coronary angiography
Aortic dissection
CHF

11

Epidemiology of Mesenteric ARTERIAL Embolism

Median age:70
SMA often involved
Near middle colic artery

12

Where is the thrombus for a mesenteric arterial embolism usually from?

Left atrium
Left ventricle
Cardiac valves

13

Which is more favorable, mesenteric arterial embolism or mesenteric arterial thrombosis?

Mesenteric arterial embolism

14

Usual Suspects for Mesenteric Arterial Thrombosis

Atherosclerotic disease
Traum
Infection

15

What is usually the site of blockage for a mesenteric arterial thrombosis?

Origin of SMA
Celiac axis

16

Epidemiology of Mesenteric Venous Thrombosis

Usually ages 48-60
Primary: clot from somewhere else & ended up in the venous system
Secondary: DVT, strangulated hernia

17

Signs/Symptoms of Mesenteric Venous Thrombosis

Diffuse pain
Anorexia
Vomiting
Diarrhea
Constipation
Hematemesis

18

Risk Factors for Mesenteric Venous Thrombosis

Hyper coagulable state
Portal HTN
Abdominal infections
Blunt abdominal trauma
Pancreatitis
Splenectomy
Malignancy in portal region
Personal or family Hx of DVT or PE
Dehydration

19

Mesenteric Venous Thrombosis Pathophysiology

Decreased blood flow
Bowel wall edema
Fluid efflux into the bowel lumen
Systemic hypotension
Increase in blood viscosity
Diminished arterial flow
Submucosal hemorrhage
Bowel infarction

20

What is non-occlusive mesenteric ischemia a result of?

Splanchnic hypoperfusion & vasoconstriction

21

Main Risk Factor for Non-occlusive Mesenteric Ischemia

Atherosclerotic disease

22

Signs/Symptoms of Non-occlusive Mesenteric Ischemia

Progressive abdominal pain
Bloating
N/V
Mental status change

23

Signs/Symptoms of Ischemia in the Colon

Mild abdominal pain
Tenderness
Rectal bleeding
Bloody diarrhea

24

What is the procedure of choice to determine if ischemia is in the colon?

Colonoscopy

25

Etiologies of Arterial Emboli

A. fib
MI

26

Etiology of Arterial Thrombosis

Atherosclerotic disease

27

Etiologies of Venous Thrombosis

Underlying disorder in coagulation
Neoplasm

28

Etiology of Non-occlusive Mesenteric Ischemia

Low flow states

29

Work Up of Acute Ischemia

Labs
Imaging: plain abdominal x-rays, abdominal CT

30

Lab Results for Acute Ischemia

Increased WBCs, hematocrit, amylase, phosphate, & serum lactate
Metabolic acidosis