What Is Superior Mesenteric Artery (SMA) Syndrome?

Medically Reviewed by Jabeen Begum, MD on November 25, 2021
3 min read

Superior mesenteric artery (SMA) syndrome is a condition that affects the duodenum — the section of the small intestine that joins the stomach. The syndrome is caused by the compressing of the duodenum by the aorta and the superior mesenteric artery (SMA). The superior mesenteric artery is one of the major arteries from the aorta (your body’s main artery). The main artery is pretty muscular and may hinder food movement through the small intestine.

In SMA the duodenum may get compressed by the arteries, preventing movement of food through the small intestine. That causes bowel obstruction that widens and damages the duodenum. This is a very rare condition of the gastrointestinal system.

Teens and young adults are most commonly affected by this syndrome, and women are likelier than men to have it. 

Superior mesenteric artery syndrome causes include:

  • Lost weight
  • Use of body casts
  • Growing rapidly
  • Prolonged bed rest
  • Abdominal surgery
  • Loss of tone in the abdominal wall
  • Lordosis (a lower back condition that causes the spine to curve inward)

There are a few symptoms that might indicate you have superior mesenteric artery syndrome. Different individuals may go through different symptoms of the same condition. Some of them include:

  • Abdominal pain (after eating)
  • Nausea
  • Indigestion
  • Vomiting (half an hour after eating)
  • Feeling full early
  • Heartburn
  • Food regurgitation
  • Chest pain
  • Sudden weight loss
  • Distended (swollen) abdomen
  • Belching
  • Bloating

Your doctor may make a diagnosis of superior mesenteric artery syndrome by checking you for symptoms. Sometimes, the symptoms might be non-specific. Your doctor may go on to rule out other conditions that may share symptoms and do some tests to make the diagnosis. They include:

  • Abdominal X-ray. The plain abdominal X-ray is important for ruling out other conditions and checking for bloating or distension.
  • Doppler ultrasound. This test uses sound waves that enable your doctor to monitor how blood is flowing in the blood vessels.
  • Computed tomography (CT scan). This test is done to check for bowel obstruction.
  • Hypotonic duodenography. This is a special X-ray that takes images of the duodenum.
  • Upper endoscopy. A tube with a camera at the tip is run down the throat allowing the doctor to inspect the small intestine, stomach, and esophagus.

Most times, it takes a while to diagnose superior mesenteric artery syndrome. That may lead to severe complications like:

  • Gastric pneumatosis
  • Gas collection in the portal vein
  • Duodenum obstruction by indigestible material (duodenal bezoar)
  • Gastric perforation
  • Death as a result of electrolyte imbalance

The first line of treatment for superior mesenteric artery syndrome is nonsurgical management that includes:

  • Feeding through a catheter (parenteral nutrition)
  • Gastric decompression (using a nasogastric tube)
  • Electrolyte correction
  • Fluid resuscitation
  • Posture therapy

People with superior mesenteric artery syndrome may be advised to eat very small meals. Good nutrition helps to boost the mesenteric fat pad. That may improve the symptoms of superior mesenteric artery syndrome.

Surgery may be recommended if the management approach fails. Possible surgical procedures may include:

  • Laparoscopic duodenojejunostomy
  • Gastrojejunostomy
  • Transabdominal duodenojejunostomy

Studies have found that laparoscopic duodenojejunostomy has the lowest risk for complications like infections, postoperative bowel obstruction, and anastomotic complications. Duodenojejunostomy has an 80% to 100% success rate with the least postoperative pain. The procedure also has a low risk of incisional herniation. You may not need to stay in hospital for long.

Who is the most affected? Research shows that the most people affected by superior mesenteric artery syndrome are teens and young adults. The condition can also occur in people of any age, though. The research shows that it occurs in women more than men.