The following information may help to address your question:
What is the superior mesenteric artery?
The superior mesenteric artery is a large artery in the abdominal cavity that provides blood to the small intestine
, cecum, and colon. The small intestine is the portion of the digestive system most responsible for absorption of nutrients from food into the bloodstream. Click here
to view a diagram of the superior mesenteric artery from the MERCK Manual Web site.
The superior mesenteric artery makes its way between two layers of the mesentery (membranous tissue which carries blood vessels and lymph glands and attaches organs to the abdominal wall) and crosses over the first part of the small intestine, called the duodenum. The duodenum is where partly digested foods from the stomach mix with bile from the gall bladder and digestive juices from the pancreas.
Last updated: 7/26/2012
What is superior mesenteric artery syndrome?
Superior mesenteric artery syndrome
(SMAS) is a digestive condition that occurs when the duodenum
(the first part of the small intestine) is compressed between two arteries
(the aorta and the superior mesenteric artery). This compression causes partial or complete blockage of the duodenum.
Symptoms vary based on severity, but can be severely debilitating.
Symptoms may include abdominal pain, fullness, nausea, vomiting, and/or weight loss.
SMAS typically is due to loss of the mesenteric fat pad (fatty tissue that surrounds the superior mesenteric artery). The most common cause is significant weight loss caused by medical disorders, psychological disorders, or surgery. In younger patients, it most commonly occurs after corrective spinal surgery for scoliosis
Delays in diagnosis may result in significant complications.
Depending on the cause and severity, treatment options may include addressing the underlying cause, dietary changes (small feedings or a liquid diet), and/or surgery.
Symptoms may not resolve completely after treatment.
Last updated: 7/6/2017
What are the signs and symptoms of superior mesenteric artery syndrome?
The signs and symptoms of superior mesenteric artery syndrome vary but may include:
- Feeling full quickly when eating
- Bloating after meals
- Burping (belching)
- Nausea and vomiting of partially digested food or bile-like liquid
- Small bowel obstruction
- Weight loss
- Mid-abdominal "crampy" pain that may be relieved by the prone or knee-chest position or by lying on the left side
Last updated: 5/16/2016
What causes superior mesenteric artery syndrome?
SMAS typically is due to loss of the mesenteric fat pad (fatty tissue that surrounds the superior mesenteric artery).
The superior mesenteric artery forms an angle with the abdominal aorta (due in part to the mesenteric fat pad), and part of the duodenum sits within this angled space. Anything that sharply narrows the angle between the aorta and superior mesenteric artery can cause compression of the duodenum, resulting in SMAS.
The most common cause of loss of the mesenteric fat pad is significant weight loss caused by medical disorders, psychological disorders, or surgery. Anatomic abnormalities can also contribute to SMAS. In younger patients, it most commonly occurs after corrective spinal surgery for scoliosis.
There are some reports of familial
cases of SMAS, and one report of affected identical twins
. This suggests there may be a genetic predisposition
to SMAS in some people.
There are also several reported cases of SMAS associated with celiac axis compression syndrome
Last updated: 7/6/2017
How might superior mesenteric artery syndrome be treated?
Treatment for superior mesenteric artery syndrome typically focuses on addressing the underlying cause of the condition.
For example, symptoms often improve after lost weight is restored or a body cast is removed.
Nasogastric decompression (a tube passed through the nose into the stomach) and proper positioning after eating (such as lying in the left side or standing or sitting with a knee-to-chest position) may be recommended to alleviate symptoms.
In severe cases, intravenous (IV) nutritional support and/or a feeding tube may be needed to provide enough calories. Affected people can usually then be started on oral liquids, followed by slow and gradual introduction of small and frequent soft meals as tolerated. Then, regular solid foods may be introduced. Metoclopramide
treatment to avoid vomiting may be beneficial for some people.
Surgery may be needed if other treatment strategies do not work. However, other treatment options should usually be tried for at least 4-6 weeks before considering surgery.
Surgery options are:
- Strong’s procedure: Where the duodenum is re-positioned to the right of the superior mesenteric artery
- Gastrojejunostomy: Where the jejune (the part of the intestines that continues with the duodenum) is joined directly to the stomach
- Duodenojejunostomy with or without division or resection of the fourth part of the duodenum.
Last updated: 10/4/2016
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