Mesenteric ischemia: Difference between revisions
 
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==Background==
==Background==
*Most commonly SMA, thus typically involves small bowel (especially jejunum) and right colon
[[File:Superior mesenteric a.gif|thumb|Frontal view of the superior mesenteric artery and its branches. The large vessel (blue) beside the SMA is the superior mesenteric vein. A considerable number of different branching patterns exist.]]
[[File:Colonic blood supply.png|thumb|Colonic blood supply. Pink - supply from superior mesenteric artery (SMA) and its branches: middle colic, right colic, ileocolic arteries. Blue - supply from inferior mesenteric artery (IMA) and its branches: left colic, sigmoid, superior rectal artery. 7 is for so-called Cannon-Böhm point (the border between the areas of SMA and IMA supplies), which lies at the splenic flexure.]]
*Most commonly superior mesenteric artery (SMA), thus typically involves small bowel (especially jejunum) and right colon
*Left colon uncommonly involved due to collateral flow
*Left colon uncommonly involved due to collateral flow
*Mean age = 70 years old (>70% of cases occur in women)
*Mean age = 70 years old (>70% of cases occur in women)
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#Mesenteric arterial thrombosis (ex. Vasculopath)
#Mesenteric arterial thrombosis (ex. Vasculopath)
#Nonocclusive mesenteric ischemia (ex. Hypovolemia from diuretics)
#Nonocclusive mesenteric ischemia (ex. Hypovolemia from diuretics)
#Mesenteric venous thrombosis (ex. hypercoagulable state)
#[[Mesenteric venous thrombosis]] (ex. hypercoagulable state)
 
{{Intestinal ischemia types}}


===Risk Factors===
===Risk Factors===
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| Arterial Embolism||
| Arterial Embolism||
*[[Dysrhythmia]] ([[A. Fib]])
*[[Dysrhythmia]] ([[A. Fib]])
*[[Cardiomyopathy]]
*Valve Disease
*Valve Disease
*[[Endocarditis]]
*[[Endocarditis]]
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==Differential Diagnosis==
==Differential Diagnosis==
{{Colitis types}}
{{Colitis types}}
{{Abdominal Pain DDX Diffuse}}
{{Abdominal Pain DDX Diffuse}}


==Evaluation==
==Evaluation==
[[File:Ischemicbowel.png|thumb|CT showing dilated loops of small bowel with thickened walls (black arrow), findings characteristic of ischemic bowel due to thrombosis of the superior mesenteric vein.]]
===Workup===
===Workup===
*Labs
*Labs

Latest revision as of 04:16, 27 November 2021

Background

Frontal view of the superior mesenteric artery and its branches. The large vessel (blue) beside the SMA is the superior mesenteric vein. A considerable number of different branching patterns exist.
Colonic blood supply. Pink - supply from superior mesenteric artery (SMA) and its branches: middle colic, right colic, ileocolic arteries. Blue - supply from inferior mesenteric artery (IMA) and its branches: left colic, sigmoid, superior rectal artery. 7 is for so-called Cannon-Böhm point (the border between the areas of SMA and IMA supplies), which lies at the splenic flexure.
  • Most commonly superior mesenteric artery (SMA), thus typically involves small bowel (especially jejunum) and right colon
  • Left colon uncommonly involved due to collateral flow
  • Mean age = 70 years old (>70% of cases occur in women)

Pathophysiology

4 distinct entities:

  1. Mesenteric arterial embolism (ex. Afib)
  2. Mesenteric arterial thrombosis (ex. Vasculopath)
  3. Nonocclusive mesenteric ischemia (ex. Hypovolemia from diuretics)
  4. Mesenteric venous thrombosis (ex. hypercoagulable state)

Intestinal Ischemic Disorder Types

  • Ischemic colitis
    • Accounts for 80-85% of intestinal ischemia
    • Due to non-occlusive disease with decreased blood flow to the colon.
    • Causes decreased perfusion leading to sub-mucosal or mucosal ischemia only.
    • Typical to the "watershed areas" of the colon (Splenic flexure or Sigmoid)
  • Acute mesenteric ischemia
    • Due to complete occlusion of mesenteric vessels
    • Complete transmural ischemia

Risk Factors

Risk Factors by Mesenteric Ischemia Type
Type Risk Factor
Arterial Embolism
Arterial Thrombosis
  • Atherosclerotic Disease
Venous Thrombosis
  • Prior thrombosis history
  • Hypercoagulable state (pregnancy, cancer, clotting disorder)
Nonocculsive

Clinical Features

  • Pain out of proportion to exam
    • Abdomen often soft, without guarding.
    • Pain often left sided around watershed areas of colon (splenic flexure and recto-sigmoid junction)
    • Severe, generalized, colicky
  • Bloody stools

Differential Diagnosis

Colitis

Diffuse Abdominal pain

Evaluation

CT showing dilated loops of small bowel with thickened walls (black arrow), findings characteristic of ischemic bowel due to thrombosis of the superior mesenteric vein.

Workup

  • Labs
  • CTA abdomen/pelvis (Bowel wall edema is the most common finding on CT)
  • Mesenteric angiography considered gold standard (if available, typically as a secondary study)

Diagnosis

  • Typically diagnosed on CT
  • Labs may show the following (although do not rule need for CT):

Management

General

Acute arterial embolus

  • Papaverine infusion (30-60m g/h IV) OR
  • Surgical embolectomy OR
  • Mesenteric artery bypass surgery OR
  • Retrograde open mesenteric stenting OR
  • tPA intra-arterial thrombolysis with IR
  • PLUS/MINUS surgical resection of necrotic bowel after any of above interventions
  • PLUS/MINUS 24-48 hour second-look surgery

Nonocclusive mesenteric ischemia

  • Transcatheter vasodilation via:
    • PGE1, alprostadil
    • PGI2, epoprostenol
    • Papaverine, most commonly used, though use in caution with angina, recent stroke, MI, glaucoma

Mesenteric venous thrombosis

  • Heparin/warfarin either alone or in combination with surgery
  • Up to 5% of patients require intervention beyond anticoagulation alone[6]
  • Immediate heparinization should be started even when surgical intervention is indicated
    • Decreases progression of thrombosis and improves survival
  • PLUS/MINUS tPA intra-arterial thrombolysis with IR
  • PLUS/MINUS laparotomy for evidence of bowel necrosis, peritonitis, stricture, severe GI bleeding

Chronic mesenteric ischemia

  • Angioplasty with or without stent placement or surgical revascularization

Disposition

  • Admit with consultation of one or more of the following:
    • IR
    • Vascular
    • Surgery

See Also

External Links

References

  1. ↑ Wyers MC. Acute mesenteric ischemia: diagnostic approach and surgical treatment. Semin Vasc Surg. 2010 Mar;23(1):9-20.
  2. ↑ Acute mesenteric ischemia. Curr Gastroenterol Rep 2008;10:341
  3. ↑ Klar E, Rahmanian PB, Bücker A, Hauenstein K, Jauch KW, Luther B. Acute mesenteric ischemia: a vascular emergency. Dtsch Arztebl Int. 2012 Apr;109(14):249-56 full-text, commentary can be found in Dtsch Arztebl Int 2012 Oct;109(42):709 full-text, Dtsch Arztebl Int 2012 Oct;109(42):710.
  4. ↑ Berland T, Oldenburg WA. Acute mesenteric ischemia. Curr Gastroenterol Rep. 2008 Jun;10(3):341-6.
  5. ↑ Brandt LJ, Boley SJ. AGA technical review on intestinal ischemia. American Gastrointestinal Association. Gastroenterology. 2000 May;118(5):954-68.
  6. ↑ Clair DG, Beach JM. Mesenteric Ischemia. N Engl J Med. 2016 Mar 10;374(10):959-68.
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