7.30.08 Volk. Mesenteric Ischemia

8/2/2019 7.30.08 Volk. Mesenteric Ischemia

1/16

Acute Mesenteric

Ischemia and Infarction

Matthew Volk

Morning Report7/30/2008


2/16

A First Big Distinction

Mesenteric Ischemia ischemia of thesmall bowel, usually 2/2 an acute cause

involving the SMA or SMV. Ischemic colitis ischemia of the colon,

rarely with a known acute precipitating

cause.


3/16

Superior Mesenteric Artery (SMA)

Largest caliber vessel + 45-degree anglemakes it most commonly occluded

Celiac Trunk

IMA

SMA

Aorta


4/16

Superior Mesenteric Artery (SMA)

Emboli occlude past the middle colic,causing small bowel ischemia

SMAMiddle Colic

Right Colic

Ileocolic

Jejunal & IlealArteries

Occlusion

Point


5/16

Etiologies of Acute Mesenteric

Ischemia (AMI) SMA Occlusion (at least 60% of cases)

Embolism: MI, Afib, Endocarditis, Valve d/o

Thrombosis: Atherosclerosis plaque rupture

Nonocclusive Mesenteric Ischemia (NOMI)

Atherosclerosis + shock + vasopressors

Mesenteric Venous Thrombosis (MVT)

Primary clotting disorder


6/16

Etiologies of Acute Mesenteric

Ischemia (AMI) Focal small bowel ischemia - rare

Partial malrotation, volvulus, mesenteric

hematoma, strangulated hernia

Unknown

?Mesenteric small vessel disease


7/16

History & Physical

Classic Presentation:

Rapid onset of severe, unrelenting

periumbilical pain Pain out of proportion to findings on

physical examination.

Nausea and vomiting Forceful/urgent bowel evacuation

Risk factors for acute mesenteric ischemia


8/16


9/16

History & Physical

Mesenteric Venous Thrombosis:

Fever

Abdominal distension

Hemoccult positive stool


10/16

Laboratory Findings

Anion gap metabolic acidosis

Elevated arterial/venous lactate

Leukocytosis

Hemoconcentration

Elevated LDH, amylase, AST, and CPK Elevated K and Phos are late signs


11/16

Radiology

Plain films thumbprinting, thickenedbowel (


12/16

Differential Diagnosis

Other serious conditions to consider:

Pancreatitis

Acute Diverticulitis

Acute Cholecystitis

Small bowel obstruction Perforation of a viscous

Ruptured aneurysm


13/16

Treatment

Resuscitation with fluids/blood products

Anticoagulation

Infusion of a vasodilator

Glucagon systemically OR

Papaverine through a catheter


14/16

From Ischemia to Infarction

Marked by peritoneal signs, fever

Emergent laporatomy

Restoration of interrupted blood flow witharteriotomy or bypass graft

Resection of infarcted bowel

Second-look in 24-48 hoursVasodilators and careful pressor use


15/16

A Word on Ischemic Colitis

Presentation: less & more focal pain(usually left-sided), more bloody diarrhea,

>90% are over 60 years old. Etiology rarely identified: ?small vessel

disease +/- hypoperfusion

Episodes usually self limited except whenstricture or gangrene develops

Colonoscopy is initial evaluation of choice


16/16

References

Netter FH, Atlas of Human Anatomy

Oldenburg et al. Arch Intern Med 164:1054 2004

Scott JR et al. AJR 113:2 Acute MesentericInfarction 1971

UptoDate Online: Article on Acute Mesenteric

Ischemia UptoDate Online: Article on Ischemic colitis

Documents

7.30.08 Volk. Mesenteric Ischemia