Ischemic Bowel Disease Flashcards

1
Q

What are the patterns of Ischemic Bowel Disease?

A

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

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2
Q

4 Main Causes of Acute Mesenteric Ischemia

A

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

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3
Q

How much cardiac output does the intestine take?

A

10-35%

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4
Q

Regulation of Intestinal Circulation

A
Perfusion pressure
Neural & hormonal mechanisms
Sympathetic nervous system
Renin-angiotensis system
Vasopressin
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5
Q

Activity of Vasopressin

A

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

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6
Q

Hallmarks of Clinical Presentation of Ischemic Bowel Disease

A

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

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7
Q

Clinical Presentation as Ischemia Worsens

A
Abdominal distention
Absent bowel sounds
Peritoneal signs
\+/- feculant odor to the breath
N/V
Frequent BM
Occult blood in stool
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8
Q

Occlusive Clinical Syndromes

A

Mesenteric arterial embolism
Mesenteric arterial thrombosis
Mesenteric venous thrombosis

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9
Q

Non-occulusive Clinical Syndromes

A

Hypoperfusion

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10
Q

Risk Factors with Acute Mesenteric ARTERIAL Embolism

A
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
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11
Q

Epidemiology of Mesenteric ARTERIAL Embolism

A

Median age:70
SMA often involved
Near middle colic artery

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12
Q

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

A

Left atrium
Left ventricle
Cardiac valves

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13
Q

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

A

Mesenteric arterial embolism

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14
Q

Usual Suspects for Mesenteric Arterial Thrombosis

A

Atherosclerotic disease
Traum
Infection

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15
Q

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

A

Origin of SMA

Celiac axis

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16
Q

Epidemiology of Mesenteric Venous Thrombosis

A

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

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17
Q

Signs/Symptoms of Mesenteric Venous Thrombosis

A
Diffuse pain
Anorexia
Vomiting
Diarrhea
Constipation
Hematemesis
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18
Q

Risk Factors for Mesenteric Venous Thrombosis

A
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
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19
Q

Mesenteric Venous Thrombosis Pathophysiology

A
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
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20
Q

What is non-occlusive mesenteric ischemia a result of?

A

Splanchnic hypoperfusion & vasoconstriction

21
Q

Main Risk Factor for Non-occlusive Mesenteric Ischemia

A

Atherosclerotic disease

22
Q

Signs/Symptoms of Non-occlusive Mesenteric Ischemia

A

Progressive abdominal pain
Bloating
N/V
Mental status change

23
Q

Signs/Symptoms of Ischemia in the Colon

A

Mild abdominal pain
Tenderness
Rectal bleeding
Bloody diarrhea

24
Q

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

A

Colonoscopy

25
Q

Etiologies of Arterial Emboli

A

A. fib

MI

26
Q

Etiology of Arterial Thrombosis

A

Atherosclerotic disease

27
Q

Etiologies of Venous Thrombosis

A

Underlying disorder in coagulation

Neoplasm

28
Q

Etiology of Non-occlusive Mesenteric Ischemia

A

Low flow states

29
Q

Work Up of Acute Ischemia

A

Labs

Imaging: plain abdominal x-rays, abdominal CT

30
Q

Lab Results for Acute Ischemia

A

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

31
Q

Findings on Plain Films for Acute Ischemia

A
Pneumatosis intestinalis
Portal venous gas
Thickened bowel wall with thumb-printing
Air-fluid levels
Dilated bowel loops
Gasless abdomen
32
Q

Define Pneumoatosis Intestinalis

A

Gas cysts in the bowel WALL which is suggestive of necrotizing enterocolitis

33
Q

Define Portal Venous Gas

A

Accumulation of gas in the portal vein & it’s branches

34
Q

What views do you want for plain films in an acute bowel?

A

Upright & supine

35
Q

What is the preferred imaging study for an acute bowel?

A

CT

36
Q

What kind of contrast do you need for an abdominal CT looking for acute bowel ischemia?

A

Oral
IV
CTA: just IV

37
Q

CT Findings in Acute Ischemia

A
Bowel wall thickening
Bowel dilation
Fat stranding
Ascites
Varying degrees of attenuation
Pneumatosis & portomesenteric gas
38
Q

Define Fat Stranding

A

Caused by fluid & inflammation that has gone out into the fat

39
Q

What study is better at diagnosing venous occlusions, CTA or MRA?

A

MRA

40
Q

Indications for Mesenteric Percutaneous Ateriography

A

Diagnosis in doubt after non-invasive measures

Diagnosis fairly certain & need consideration for percutaneous treatment or surgical planning

41
Q

Contraindication for Mesenteric Percutaneous Arteriography

A

Venous occlusion

42
Q

Treatment of Acute Bowel Ischemia in General

A
Hemodynamic monitoring & support
Correction of metabolic acidosis
Broad spectrum antibiotics
NG tube for gastric decompression
Vasopressors with less effect on bowel perfusion: dobutamine, low dose dopamine, milrinone
Anticoagulation
Correction of arrhythmias
Imaging
43
Q

What is the gold standard diagnostic study for acute arterial ischemia?

A

Mesenteric Angiography

44
Q

Treatment for Mesenteric Arterial Embolism

A

Surgery & embolectomy

Local infusion of thrombolytic therapy

45
Q

Treatment for Mesenteric Arterial Thrombosis

A

Surgery with thrombectomy & revascularization or heparinization

46
Q

Treatment for Mesenteric Venous Thrombosis

A

Heparinization + resection of infarcted bowel

47
Q

Treatment for Non-occlusive Mesenteric Ischemia

A

Papaverine infusion during angiography
Reverse underlying conditions
Repeat angiography in 24 hours
Surgical exploration in patients with peritoneal signs

48
Q

Care for Ischemic Bowel Disease Patients

A
Cardiac monitor
Venous access
Oxygen
Fluid resuscitation
Broad-spectrum antibiotics
Surgery
49
Q

Chronic Mesenteric Ischemia

A

Intestinal angina
Episodic or constant intestinal hypoperfusion
Secondary to atherosclerosis
Strongly associated with meals