Ischemic Bowel Disease Flashcards
What are the patterns of Ischemic Bowel Disease?
Small and/or large bowel
Diffuse or localized
Segmental or focal
Superficial or transmural
4 Main Causes of Acute Mesenteric Ischemia
SMA embolism (50%)
SMA thrombosis (15-25%)
Non-occlusive ischemia (20-30%)
Mesenteric venous thrombosis (5%)
How much cardiac output does the intestine take?
10-35%
Regulation of Intestinal Circulation
Perfusion pressure Neural & hormonal mechanisms Sympathetic nervous system Renin-angiotensis system Vasopressin
Activity of Vasopressin
Causes mesenteric arterial vasoconstriction & venous dilation
Reduces portal venous pressure in patients bleeding with portal HTN
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
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
Occlusive Clinical Syndromes
Mesenteric arterial embolism
Mesenteric arterial thrombosis
Mesenteric venous thrombosis
Non-occulusive Clinical Syndromes
Hypoperfusion
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
Epidemiology of Mesenteric ARTERIAL Embolism
Median age:70
SMA often involved
Near middle colic artery
Where is the thrombus for a mesenteric arterial embolism usually from?
Left atrium
Left ventricle
Cardiac valves
Which is more favorable, mesenteric arterial embolism or mesenteric arterial thrombosis?
Mesenteric arterial embolism
Usual Suspects for Mesenteric Arterial Thrombosis
Atherosclerotic disease
Traum
Infection
What is usually the site of blockage for a mesenteric arterial thrombosis?
Origin of SMA
Celiac axis
Epidemiology of Mesenteric Venous Thrombosis
Usually ages 48-60
Primary: clot from somewhere else & ended up in the venous system
Secondary: DVT, strangulated hernia
Signs/Symptoms of Mesenteric Venous Thrombosis
Diffuse pain Anorexia Vomiting Diarrhea Constipation Hematemesis
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
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