Superior mesenteric artery (SMA) syndrome is a rare form of compression of the small intestine.
The syndrome occurs when the duodenum in the upper part of the small intestine is compressed.
Although it’s treatable, delayed diagnosis can lead to more severe symptoms or eventually death.
This syndrome has gone by many other names like Cast syndrome, Wilkie syndrome, Chronic duodenal ileus, and Mensenteric root syndrome, among others.
Symptoms
The symptoms are generally nonspecific and they vary from person to person.
Symptoms might develop rapidly in some people and intensify gradually in others.
However, common symptoms are weight loss, nausea, swollen belly, vomiting of food that is partially digested, and epigastric pain which gets worse when you lie on your back.
Causes
The duodenum passes between two arteries, the abdominal aorta, and the superior mesenteric artery.
Typically, there’s a pad of fat that acts like a cushion for the SMA, keeping it away from the spine, renal vein, and duodenum.
For a person with SMA syndrome, this mesenteric fat pad is too small, and the SMA presses the duodenum against the abdominal artery.
There are a lot of reasons why the mesenteric fat pad might be small but it’s majorly because of significant weight loss.
Some of the causes of weight loss associated with this syndrome are anorexia nervosa, Malabsorption syndrome, and hypermetabolism resulting from injury or burns.
SMA syndrome usually develops in younger patients after spinal surgery to treat scoliosis.
Who gets SMAS?
SMA is a very rare condition and about 0.1 and 0.3 percent of the U.S. population have the syndrome.
Anyone can have the SMA syndrome, but it’s most common between the ages of 10 and 39 and it’s 50 percent more common in females.
It’s not considered to be an inherited disease and most people who have SMA syndrome don’t have relatives who share the diagnosis.
There are however some reported cases of the syndrome within families or identical twins.
Some people are born with slight physical differences that could increase their risk of SMA syndrome like differences in the length of a ligament that supports your duodenum.
People with these differences are unaware of them until they’re diagnosed with SMA syndrome.
Potential Complications
Compression of the duodenum can also cause the compression of your renal vein, leading to a condition called nutcracker syndrome.
It’s possible to have both diseases at the same time but it is not common.
Other complications of SMA syndrome include gastritis, bile reflux, peptic and duodenal ulcers, malnutrition, dehydration, and low blood pressure, among others.
Treatment
Doctors usually focus on addressing the cause of the compression while treating SMA syndrome.
This means they first take a noninvasive approach to restore the mesenteric fat pad to relieve pressure on your duodenum like controlled weight gain.
If the patient is severely malnourished, intravenous fluids or a feeding tube are used for feeding.
When the doctor deems it safe, then they can begin taking liquid nourishment orally and then move up to calorie-rich soft foods and solids.
Medications to prevent vomiting will also be prescribed.
However, if this approach doesn’t work, surgery may be required.
Surgery may involve repositioning the duodenum or SMA or bypassing a portion of the small intestine to avoid the pinch point.
