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1036 PART 9: Gastrointestinal Disorders

• Bakker OJ, van Santvoort HC, van Brunschot S, et al. Endoscopic
transgastric vs surgical necrosectomy for infected necrotizing • Arterial phase abdominal and pelvic computed tomographic (CT)
pancreatitis: a randomized trial. JAMA. 2012;307(10):1053-1061. mesenteric angiography is the investigation of choice, offering accu-
rate diagnostic evaluation. However, selective mesenteric angiography
• Banks PA, Bollen TL, Dervenis C, et al. Classification of acute offers therapeutic options, whereas duplex ultrasonography may not be
pancreatitis—2012: revision of the Atlanta classification and defi- definitive. Frequently, the diagnosis is confirmed only at laparotomy.
nitions by international consensus. Gut. 2013;62(1):102-111. • Treatment is most commonly surgical, with restoration of flow by
• Halangk W, Lerch MM, Brandt-Nedelev B, et al. Role of cathepsin embolectomy, bypass, or angioplasty (antegrade or retrograde);
B in intracellular trypsinogen activation and the onset of acute vasodilator infusion therapy; thrombolysis and resection of nonvi-
pancreatitis. J Clin Invest. 2000;106(6):773-781. able intestine; and liberal use of “second look” laparotomy.
• Petrov MS, Kukosh MV, Emelyanov NV. A randomized controlled • Nonocclusive mesenteric ischemia (NOMI) has a high mortality
trial of enteral versus parenteral feeding in patients with predicted rate, and early diagnosis and treatment are important for improv-
severe acute pancreatitis shows a significant reduction in mortality ing survival in patients with this condition.
and in infected pancreatic complications with total enteral nutri-
tion. Dig Surg. 2006;23(5-6):336-345.
• Sadr-Azodi O, Andrén-Sandberg Å, Orsini N, Wolk A. Cigarette
smoking, smoking cessation and acute pancreatitis: a prospective
population-based study. Gut. 2012;61(2):262-267. Acute mesenteric ischemia is a relatively rare but often fatal clinical
• Tenner S, Baillie J, DeWitt J, Vege SS. American College of entity. Although little data exist on its true incidence, data from the
Swedish Vascular Registry suggest that it may account for just 1% of
Gastroenterology Guideline: management of acute pancreatitis. reconstructions for acute thromboembolism. Contemporary series,
1
Am J Gastronterol. 2013;108(9):1400-1416. however, continue to report a mortality rate of between 32% and 48%.
2,3
• van Santvoort HC, Bakker OJ, Bollen TL, et al. A conservative and Although autopsy studies suggest that atherosclerosis affecting the
minimally invasive approach to necrotizing pancreatitis improves mesenteric arteries is common (6%-10%), symptomatic mesenteric
4
outcome. Gastroenterology. 2011;141(4):1254-1263. occlusive disease is rare. However, of patients presenting with acute mes-
• van Santvoort HC, Besselink MG, Bakker OJ, et al. A step-up enteric ischemia, one large series found that 43% had prior symptoms
5
approach or open necrosectomy for necrotizing pancreatitis. N of chronic mesenteric ischemia. The spectrum of mesenteric ischemia
Engl J Med. 2010;362(16):1491-1502. includes occlusive disease secondary to atherosclerotic occlusion with
• Villatoro E, Mulla M, Larvin M. Antibiotic therapy for prophy- thrombosis, embolism, mesenteric venous thrombosis, and nonocclu-
laxis against infection of pancreatic necrosis in acute pancreatitis. sive mesenteric ischemia due to vasospasm (Table 109-1). At its most
Cochrane Database of Systematic Reviews 2010, Issue 5. Art. No.: florid, it may present with mesenteric infarction, intestinal perforation,
CD002941. DOI: 10.1002/14651858.CD002941.pub3. and septic circulatory collapse. This relatively rare but often fatal clini-
cal entity must be considered early in the differential diagnosis of any
patient with abdominal symptoms or signs but especially those with
pain out of proportion to physical findings. Also a history of intestinal
REFERENCES angina, peripheral vascular disease, cardiac dysfunction, aortic surgery
Complete references available online at www.mhprofessional.com/hall or recent aortic catheterization, hypotension, or prothrombotic state
increases the risk of mesenteric vascular disease. Noninvasive tests for
mesenteric ischemia lack specificity and sensitivity, which mandates that
the diagnosis often requires a high index of suspicion, supplemented
CHAPTER Mesenteric Ischemia by a liberal use of computed tomographic angiogram (CTA) when
uncertainty remains. Where doubt exists in the presence of emerging
109 Hassan A. Al-Zahrani acute abdominal signs or clinical deterioration, diagnostic laparotomy
is indicated. This discussion will focus on the etiology, pathophysiology,
Thomas Lindsay
diagnosis, and management of acute mesenteric ischemia.
ANATOMY AND DYNAMICS
KEY POINTS OF THE MESENTERIC CIRCULATION

• Acute mesenteric ischemia is an infrequent but deadly clinical The mesenteric circulation is supplied in series by the three major mid-
entity. When diagnosis is delayed, it is almost always fatal; there- line branches of the abdominal aorta, namely the celiac artery, supplying
fore, a high index of suspicion is required, especially in those at the foregut, hepatic, and splenic beds; the superior mesenteric artery
high risk: the elderly, those with cardiac dysfunction, patients with (SMA), supplying the midgut; and the inferior mesenteric artery (IMA)
diffuse atherosclerosis, and those following aortic and cardiac and the internal iliac arteries, supplying the hindgut. An extensive
surgery or arterial catheterization. network of actual and potential sites of collateralization exists between
• The etiology of acute mesenteric ischemia may be embolic, throm- individual branch territories and their neighbors, as well as the systemic
circulation. The celiac territory may gain supply proximally across the
botic, primary vasoconstrictive, or secondary to venous thrombosis. diaphragm from the phrenic and esophageal vessels (that arise from
Chronic ischemia is usually due to flow-limiting lesions (mesenteric the aorta) and distally from the SMA via the gastroduodenal artery, includ-
stenosis or occlusions) in the presence of inadequate collateralization. ing the superior and inferior gastroduodenal arteries. The SMA territory
• Classic symptoms of acute intestinal ischemia are central abdominal may be perfused from the celiac artery, as mentioned, or from the IMA
pain (often out of proportion to the benign abdominal examina- territory via the arch of Riolan, a collateral that runs in the midmesentery
tion), weight loss (an important clue even in the acute presentation), and is fed via the ascending branch of the left colic artery (Fig. 109-1).
bowel emptying, and altered bowel function (vomiting, bloating, The IMA territory may collateralize proximally, as described, or dis-
constipation, or diarrhea). Once signs of peritonitis or bloody diar- tally via the inferior hemorrhoidal arteries from the internal iliac
rhea are present, shock, sepsis, and death almost always follow. artery. Blood from the pelvis may collateralize to the SMA or above
from the communications between the sigmoidal/hemorrhoidal

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