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Be sure to keep mesenteric ischemia on your radar in your younger patients


 

CHICAGO – Early recognition of mesenteric ischemia in young adults and children is essential to prevent bowel loss and other serious consequences associated with this rare condition, Dr. Michael Dalsing said at a vascular surgery symposium.

Mesenteric ischemia is generally seen in the elderly as the result of atherosclerotic and embolic occlusive diseases. Because young adults and children typically don’t have any of the telltale associated comorbidities such as cardiac arrhythmia or coronary artery disease to point physicians in this direction, the diagnosis of mesenteric ischemia is often delayed or misinterpreted as appendicitis, cholecystitis, or intra-abdominal abscess, he said.

Patrice Wendling/Frontline Medical News

Dr. Michael Dalsing

Among 26 young adults under age 40 years who presented with acute mesenteric ischemia, only 6 were properly diagnosed preoperatively (Wien. Med. Wochenschr. 2012;162:349-53). The postoperative complication and mortality rates reached 61.5% and 27%, which is typical in this population, despite their otherwise good health, said Dr. Dalsing, director of vascular surgery at Indiana University, Indianapolis.

The hallmarks of acute mesenteric ischemia are standard in both young and old patients and include abdominal pain out of proportion to the physical exam, nausea, vomiting, and/or diarrhea. Acidosis, acute renal failure, and septic shock/sepsis can develop in roughly half of patients with more extensive liver or bowel ischemia or necrosis. The signs and symptoms of chronic ischemia are weight loss, food fear, and postprandial abdominal pain.

"For chronic mesenteric ischemia, what’s the important message? Consider the diagnosis," Dr. Dalsing said. "Do the imaging, find out what you have, and then you can worry about ancillary testing because, in general, these aren’t going to be your typical etiologies. In fact, they’re not standard fare at all."

The broad and atypical list of etiologies to consider in those under age 40 years include congenital aortic anomalies, hypercoagulable states, inflammatory conditions, collagen vascular disorders, and environmental agents such as cocaine use, smoking, or trauma. While MI is often suspected in those using cocaine, the vasoconstrictive effects of the drug can also cause vasospasm of the smaller branches of the mesenteric vessels, leading to nonocclusive mesenteric ischemia, he explained.

Once a diagnosis of chronic mesenteric ischemia is made in a young patient, management consists of fluid resuscitation, broad spectrum antibiotics, bowel rest, and imaging, often with a CT angiogram. The need for additional work-up, including hypercoagulable and inflammatory marker panels, varies based on initial clinical symptoms.

If vascular compromise is identified, the overall management goals should be to remove frankly necrotic bowel, reperfuse ischemic bowel, limit the resection length when possible to prevent short-gut syndrome, and treat the underlying etiology, Dr. Dalsing advised. Anticoagulation is also integral to prevent thrombus propagation.

Just six cases of mesenteric ischemia have been diagnosed at Indiana University in young adults over the last 16 years, with Takayasu’s arteritis the most common etiology, he noted. This includes a 20-year-old woman with a 5-year history of Takayasu’s, who presented with worsening abdominal pain despite remission of her Takayasu’s, as indicated by a normal sedimentation rate.

Repeat CT imaging revealed more than 70% celiac artery stenosis and more than 50% stenosis of the superior mesenteric artery (SMA). A median arcuate ligament division and celiac and SMA bypass graft, both with reverse saphenous vein originating from bilateral iliac arteries, was performed. "She’s had dramatic improvement" in her symptoms and remains on clopidogrel (Plavix) and low-dose steroids, Dr. Dalsing said.

Courtesy Wikimedia Commons/James Heilman, MD/Creative Commons Attribution

CT of an ischemic bowl due to thrombosis of the superior mesenteric vein. Note the dilated bowel with a thickened bowel wall.

A second patient with Takayasu’s presented with a 4-month history of abdominal pain, a 50-pound weight loss, stenosis of all major mesenteric arteries, and bowel pneumatosis. Despite this, her sedimentation rate was only slightly elevated at 33 mm/hour, and all other coagulation and inflammatory tests were normal. She remains symptom free at 2 years on daily aspirin after undergoing an emergent right common iliac-to-SMA bypass graft with reversed saphenous vein and bowel resection.

In cases in which bypass grafting is necessary, the internal iliac artery is the preferred conduit in children since the saphenous vein is very thin walled and thus, more prone to aneurysmal degeneration, Dr. Dalsing observed. In grown patients, the saphenous vein may be the best conduit in terms of ease of harvest and adequate length for even bifurcated grafts or C-loop alignment.

During postoperative follow-up, special effort should be taken because of the young age of these patients to reduce the detrimental effects of radiation from recurrent CT angiograms, he said. Patients with symptomatic improvement are followed at 1 month postoperatively with a physical exam that includes their weight and a mesenteric duplex to evaluate graft or stent patency. This is repeated every 6 months for 1-2 years, and decreased to yearly visits, if no disease progression is detected. More aggressive imaging with CT angiography is reserved for patients with recurrent symptoms or if duplex ultrasound is insufficient or shows progressive disease, he said at the meeting, sponsored by Northwestern University.

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