Overview
Superior mesenteric artery syndrome, also known as Wilkie disease, duodenal artery compression syndrome, and benign duodenal stasis, is an acute or chronic intestinal obstruction caused by compression of the horizontal part of the duodenum by the superior mesenteric artery (SMA) or its branches. It occurs most often in 20 to 30 years old, about 60% of women, and is more common in long and thin body types.
Causes
1. Congenital factors
Anatomical variation or change of superior mesenteric artery. The transverse and ascending segments of the duodenum cross the third lumbar vertebrae, the abdominal aorta, and the paravertebral muscles from right to left. The superior mesenteric artery originates from the abdominal aorta at approximately the level of the first lumbar vertebra, forms an acute angle with the abdominal aorta, and spans the transverse or ascending duodenal segment before entering the mesentery of the small intestine. For this reason, these two portions of the duodenum are located within the acute angle gap formed by the superior mesenteric artery and the abdominal aorta, and the normal angle of this acute angle averages 40 to 60. If the angle between the superior mesenteric artery and the abdominal aorta is too small, the superior mesenteric artery can compress the transverse and ascending duodenum on the vertebral body or the abdominal aorta, resulting in narrowing of the lumen of the intestines and obstruction. In patients with clinical symptoms of obstruction, the angle of this acute angle is mostly 15.~20.
2. Acquired factors
(1) Inflammation and adhesion around duodenum, enlarged lymph nodes near the root of superior mesenteric artery and severe malnutrition, wasting, causing gastrointestinal prolapse and forming the pulling of superior mesenteric artery, resulting in twisting of duodenum and formation of stagnant obstruction by pressure.
(2) In addition, surgical factors such as esophageal cancer, because of postoperative (scar contraction) stomach and duodenum are pulled upward, so that the opening position of superior mesenteric artery is relatively shifted downward; after the correction of anterior spine protrusion and severe lumbar dorsal deformity, the angle of the abdominal aorta and superior mesenteric artery can be made smaller, causing complete or incomplete intestinal obstruction.
(3) People with long, thin, and weak body types or mental or nervous instability are prone to this syndrome.
Symptoms
Symptoms mostly appear after the age of 30. The course of the disease is generally long, with intermittent recurrent symptoms, with recurrent postprandial nausea, vomiting, abdominal pain, abdominal distension as the main clinical manifestations, and with either long or short periods of remission.
1. intermittent recurrent episodes of postprandial epigastric discomfort, fullness, pain, supine position, the symptoms are obvious, the patient often find the symptoms of the onset of a change in position can alleviate the symptoms, such as side-lying, prone, chest-knee position, leaning forward to the sitting position will be placed on the knees under the jaw, and so on.
2. Erratic, nausea, vomiting, vomiting of alternate meals or persistent food and bile, abdominal pain can be relieved after vomiting. Severe vomiting can cause water and electrolyte disorders and dehydration.
3. Prolonged lack of appetite may lead to emaciation, malnutrition, vitamin deficiency.
Examination
1. X-ray barium meal examination
Barium X-ray can show the characteristic “double liquid surface sign” of duodenal obstruction. Typical manifestations are: longitudinal compression at the junction of the horizontal and ascending parts of the duodenum (“pencil sign”); barium passage is obstructed; barium can be passed after changing the position or pressurizing and massaging; the proximal duodenum can be dilated to varying degrees and there is a wave of inverse peristaltic movement.
2. Color Doppler ultrasonography
Color Doppler ultrasonography can improve the diagnosis rate, clearly show the angle between the superior mesenteric artery and the abdominal aorta and the anatomical relationship between the horizontal or ascending part of the duodenum passing through the angle, and dynamically observe the flow of intestinal contents and changes in intestinal luminal diameter due to peristaltic movement of the duodenum.
3.CT and magnetic resonance imaging
CT and magnetic resonance imaging can clearly show the dilated stomach and duodenal intestinal lumen. Magnetic resonance imaging is better than CT in vascular and soft tissue imaging, which can observe the duodenal compression and measure the degree of angle between superior mesenteric artery and abdominal aorta.
4. Endoscopy
Observation of duodenal intestinal lumen is of clinical significance to exclude intestinal lesions and to confirm the presence or absence of extrinsic compression at the level of the duodenum.
Diagnosis
1. Young and middle-aged people with long and thin bodies should consider the possibility of superior mesenteric artery syndrome in patients with repeated vomiting of bile and the food they have eaten, especially if the change of body position can alleviate the symptoms.
2. Imaging tests are helpful for diagnosis, and barium X-ray is the key to diagnosis. Color Doppler ultrasonography can improve the diagnosis rate.
Treatment
1. Internal medicine treatment
(1) Those without obvious symptoms may not need to be treated. Usually, it is better to have small amount of meals, lie down for half an hour after meals, and strengthen abdominal muscle exercise, which can reduce the symptoms. In acute attacks, fasting, gastrointestinal decompression, and anti-spasmodic drugs can be given.
(2) Conservative treatment includes: acute fasting, gastrointestinal decompression, correction of water and electrolyte disorders, nutritional support, and if necessary, total parenteral nutrition; discretionary use of atropine, scopolamine; after the symptoms are relieved, gradually regulate the diet, small meals, avoiding fiber-containing diets, combined with the change of body position and other measures for treatment.
2.Surgical treatment
When the symptoms attack frequently and the internal medicine conservative treatment is ineffective, surgical treatment can be considered. Duodenojejunostomy can be done, but must be careful.
Questions you may be concerned about
How to treat superior mesenteric artery syndrome?
The treatment of superior mesenteric artery syndrome includes conservative treatment and surgery.
1. Conservative treatment: It is applicable to the treatment of patients with superior mesenteric artery syndrome with chronic and incomplete intestinal obstruction.
Wasting is a common cause of the disease, so improving nutritional status can alleviate the condition. If the wasting is caused by psychological factors such as anorexia nervosa, corresponding psychological treatment should be given.
In the acute stage, fasting, gastrointestinal decompression, maintaining the stability of the internal environment, and nutritional support should be provided, and the treatment should be carried out by regulating the diet combined with changing the body position after the symptoms are relieved. Nutritional support treatment is preferred to enteral nutrition, which can improve the nutritional status of patients, increase the fat content of the abdominal cavity, and relieve symptoms.
2. Surgery: For patients with superior mesenteric artery syndrome who are poorly treated with conservative therapy or obstructed by mechanical factors, surgery is usually required. Commonly used surgical procedures include duodenojejunostomy, gastrojejunostomy, duodenal loop drainage and so on. The indications for surgery should be strictly controlled to minimize the occurrence of postoperative complications.
Superior mesenteric artery syndrome should be treated in strict compliance with medical advice to avoid adverse consequences.
Prognosis
The prognosis of this disease is good after correct treatment. More than half of the patients recover well after surgery. However, some patients still have nausea and vomiting within 1 week after surgery, which often aggravate the patient’s nervousness and anxiety. Comprehensive treatment should be adopted for this kind of patients, and most of them can be cured in the end.