Intensive care unit admission is indicated for patients

with unstable vital signs (tachycardia, hypotension) or

sepsis. Urgent surgery is required in patients with peri tonitis, perforation, or strangulation.

..... Discharge

None.

SUGGESTED READING

Diaz JJ Jr, Bokhari F, Mowery NT. Guidelines for management of

small bowel obstruction. 1 Trauma. 2008 Jun;64(6):165 1-64.

Markogiaunakis H, Messaris E, Dardamanis D. Acute mechanical

bowel obstruction: clinical presentation, etiology, management and outcome. World ] Gastroenterol. 2007 Jan 21;13(3):

432-7.

Miller G, Boman J, Shrier I, Gordan PH. Etiology of small bowel

obstruction. Am 1 Surg. 2000 Jul;180( l ):33-6

Vicario SJ, Price TG. Bowel obstruction and volvulus. In:

Tintinalli JE, Stapczynski JS, Ma OJ, Cline DM, Cydulka RK,

Meckler GD. Tintinalli's Emergency Medicine: A Comprehensive

Study Guide. 7th ed. New York, NY: McGraw-Hill, 20 1 1,

pp. 581-583.

Mesenteric Ischemia

Ross A. Heller, MD

Carl M. Kraemer, MD

Key Points

• The classic presentation of mesenteric ischemia is

acute abdominal pain that is "out of proportion" to

exam.

• The majority of patients with mesenteric ischemia have

an embolus due to atrial fibri llation.

INTRODUCTION

Acute mesenteric ischemia is a syndrome characterized by

inadequate blood flow to the mesentery with resultant

hypoxemia of the tissue. Over time, the hypoxemia results

in tissue break down with loss of bowel integrity.

The incidence of mesenteric ischemia is reported to be

0. 1 o/o of hospitalized patients, and this number is thought

to be increasing as the average age of the population

increases. The mortality is more than 60%. Delay in diagnosis is common, but with reports that early intervention

increases survival rate, it is important to always have this

diagnosis in the differential for elderly patients presenting

with abdominal pain.

Four etiologies of mesenteric ischemia are described,

and each has different risk factors and variation in presentation. The most common cause of mesenteric ischemia is

arterial emboli (SO%), usually owing to atrial fibrillation.

Arterial thrombosis at the narrowing of mesenteric arteries

in patients with atherosclerosis is responsible for 20% of

acute presentations. These patients frequently have other

forms of atherosclerosis such as coronary artery disease.

Mesenteric venous thrombosis, which may be associated

with peripheral deep vein thrombosis, accounts for 5-lOo/o

of presentations. Nonocclusive mesenteric ischemia is seen

in up to 20-25% of presentations. It is due to low flow

states typically seen in shock syndromes. It occurs most

• Morbidity and morta lity remains very high despite

advances in care, and survival is dependent on early

recognition and treatment.

• Obtain early surgical consu ltation if mesenteric ischemia

is suspected.

commonly in hospitalized patients and is difficult to

diagnose.

The mesenteric vessel affected is responsible for the

presenting symptoms and area of injury. The superior

mesenteric artery (SMA) is the most commonly involved

site because of the sharp takeoff of this vessel from the

aorta.