View source for Mesenteric ischemia

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==Background==

[[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
*Mean age = 70 years old (>70% of cases occur in women)


===Pathophysiology===

4 distinct entities:
#Mesenteric arterial embolism (ex. Afib)
#Mesenteric arterial thrombosis (ex. Vasculopath)
#Nonocclusive mesenteric ischemia (ex. Hypovolemia from diuretics)
#[[Special:MyLanguage/Mesenteric venous thrombosis|Mesenteric venous thrombosis]] (ex. hypercoagulable state)

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{{Intestinal ischemia types}}
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===Risk Factors===

{| class="wikitable sortable"
|+ Risk Factors by Mesenteric Ischemia Type
|-
! scope="col" | '''Type'''
! scope="col" | '''Risk Factor'''
|-
| Arterial Embolism||
*[[Special:MyLanguage/Dysrhythmia|Dysrhythmia]] ([[Special:MyLanguage/A. Fib|A. Fib]])
*[[Special:MyLanguage/Cardiomyopathy|Cardiomyopathy]]
*Valve Disease
*[[Special:MyLanguage/Endocarditis|Endocarditis]]
*[[Special:MyLanguage/MI|MI]]
|-
| [[Special:MyLanguage/Arterial thrombosis|Arterial Thrombosis]]||
*Atherosclerotic Disease
|-
| [[Special:MyLanguage/Venous thrombosis|Venous Thrombosis]]||
*Prior thrombosis history
*Hypercoagulable state ([[Special:MyLanguage/pregnancy|pregnancy]], cancer, clotting disorder)
|-
| Nonocculsive||
*[[Special:MyLanguage/Hypovolemic|Hypovolemic]] state
*[[Special:MyLanguage/Heart failure|Heart failure]]
*[[Special:MyLanguage/Myocardial infarction|Myocardial infarction]] with decrease output
*[[Special:MyLanguage/Sepsis|Sepsis]]
*[[Special:MyLanguage/Diuretic|Diuretic]] use
|}


==Clinical Features==

*[[Special:MyLanguage/Abdominal pain|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
*[[Special:MyLanguage/GI bleed|Bloody stools]]


==Differential Diagnosis==

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{{Colitis types}}
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{{Abdominal Pain DDX Diffuse}}
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==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===

*Labs
**CBC
**Chemistry
**[[Special:MyLanguage/LFTs|LFTs]]
**Lipase
**[[Special:MyLanguage/Lactate|Lactate]]
**Consider [[Special:MyLanguage/UA|UA]]
*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):
**[[Special:MyLanguage/Lactate|Lactate]] (higher later)
**WBC (often >15K)
**Chemistry (metabolic acidosis)
**[[Special:MyLanguage/Hyperphosphatemia|Hyperphosphatemia]]


==Management==


===General===

*Aggressive [[Special:MyLanguage/IVF|IVF]] resuscitation, continued after revascularization due to capillary leak
**Correct [[Special:MyLanguage/electrolyte imbalances|electrolyte imbalances]] prior to IV contrast or surgical exploration<ref>Wyers MC. Acute mesenteric ischemia: diagnostic approach and surgical treatment. Semin Vasc Surg. 2010 Mar;23(1):9-20.</ref>
*[[Special:MyLanguage/Analgesia|Analgesia]] (usually [[Special:MyLanguage/Opioids|Opioids]]
*IV [[Special:MyLanguage/antibiotics|antibiotics]] - broad spectrum antibiotics to prevent sepsis <ref>Acute mesenteric ischemia. Curr Gastroenterol Rep 2008;10:341</ref>
**Second-generation [[Special:MyLanguage/cephalosporin|cephalosporin]] plus [[Special:MyLanguage/metronidazole|metronidazole]]<ref>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.</ref>, '''OR'''
**[[Special:MyLanguage/Levofloxacin|Levofloxacin]] 500 mg IV q24 hours PLUS [[Special:MyLanguage/Metronidazole|Metronidazole]] 15 mg/kg IV LOAD over 1 hour, for severely ill, maintenance 500 mg IV q6 hours,<ref>Berland T, Oldenburg WA. Acute mesenteric ischemia. Curr Gastroenterol Rep. 2008 Jun;10(3):341-6.</ref> OR
**[[Special:MyLanguage/Piperacillin/tazobactam|Piperacillin/tazobactam]] 3.375 mg IV q6 hours
*[[Special:MyLanguage/Anticoagulation|Anticoagulation]] with [[Special:MyLanguage/heparin|heparin]] is usually appropriate in all patients with mesenteric ischemia, with exception of those with typical contraindications
**Some experts will recommend delaying heparin for 48 hours due to risk for intraluminal bleeding in bowels<ref>Brandt LJ, Boley SJ. AGA technical review on intestinal ischemia. American Gastrointestinal Association. Gastroenterology. 2000 May;118(5):954-68.</ref>


===Acute arterial embolus===

*Papaverine infusion (30-60m g/h IV) OR
*Surgical embolectomy OR
*Mesenteric artery bypass surgery OR
*Retrograde open mesenteric stenting OR
*[[Special:MyLanguage/tPA|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:
**[[Special:MyLanguage/PGE1|PGE1]], alprostadil
**PGI2, [[Special:MyLanguage/epoprostenol|epoprostenol]]
**Papaverine, most commonly used, though use in caution with angina, recent stroke, MI, glaucoma


===Mesenteric venous thrombosis===

*[[Special:MyLanguage/Heparin|Heparin]]/[[Special:MyLanguage/warfarin|warfarin]] either alone or in combination with surgery
*Up to 5% of patients require intervention beyond anticoagulation alone<ref>Clair DG, Beach JM. Mesenteric Ischemia. N Engl J Med. 2016 Mar 10;374(10):959-68.</ref>
*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==

*[[Special:MyLanguage/Abdominal pain|Abdominal pain]]


==External Links==


==References==

<references/>

[[Category:GI]]
[[Category:Vascular]]
[[Category:Surgery]]
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