Superior mesenteric artery syndrome

Introduction to superior mesenteric artery syndrome Superior mesenteric artery syndrome (superiormesenteryarterysyndrome), also known as benign duodenal stasis, is the superior mesenteric artery or its branches oppress the duodenal horizontal or ascending part of the duodenum intermittent episodes of chronic intestinal obstruction. basic knowledge The proportion of illness: 0.005%-0.008% Susceptible people: no specific people Mode of infection: non-infectious Complications: acute gastric dilatation, nausea and vomiting

Cause of superior mesenteric artery syndrome

(1) Causes of the disease

Due to changes in local anatomy caused by congenital anatomical variations and/or acquired factors, the superior mesenteric artery is forced to the duodenal level, resulting in duodenal stasis and dilation.

Congenital anatomical variation

(1) The angle between the superior mesenteric artery and the abdominal aorta is too small: the duodenal horizontal part is located behind the retroperitoneum, from the right to the left across the third lumbar vertebrae and the abdominal aorta, with the superior mesenteric artery vascular nerve The sheath is straddle, the superior mesenteric artery is generally separated at the level of the first lumbar vertebrae, and is at an angle of 50° to 60° with the abdominal aorta. In normal adults, the inferior mesenteric artery is sometimes seen in front of the duodenal horizontal portion, if on the mesentery. The angle between the artery and the abdominal aorta is too small, or the superior mesenteric artery is too low from the branch of the abdominal aorta, which can suppress the obstruction of the duodenum passing through the middle.

(2) High position of the duodenum: Due to the short or thick duodenal suspensory ligament, the position of the duodenum is higher, causing symptoms of duodenal compression of the superior mesenteric artery.

(3) Spinal protrusion: The protrusion of the spine causes the angle between the superior mesenteric artery and the abdominal aorta to be too small.

2. Other conditions that cause the superior mesenteric artery to compress the duodenum

(1) lanky body type: lean body shape and various reasons of weight loss can weaken the mesenteric support of the duodenal horizontal part, visceral sag traction of the mesentery is often an important cause of this disease.

(2) Post-operative adhesion: Adhesive traction of the mesentery after intra-abdominal surgery can cause significant compression of the superior mesenteric artery to the duodenum.

(two) pathogenesis

The disease is caused by compression of the duodenal horizontal segment or ascending segment in the superior mesenteric artery and retroperitoneal fixed tissue (such as the abdominal aorta and spine).

1. Its mechanism

(1) An acute angle is formed between the abdominal aorta and the superior mesenteric artery.

(2) The distance between the duodenum and the superior mesenteric artery branch is shortened.

(3) Visceral drooping.

(4) Abnormal bowel bypass in the fetal period.

2. In view of the above anatomical relationship plus the following factors

(1) Rapid weight loss.

(2) The body is slender.

(3) Chronic wasting disease for a long time in bed.

(4) retroperitoneal tumors.

(5) The waist or spine plaster fixation is easy to induce the disease.

Prevention of superior mesenteric artery syndrome

Prevention work starts with the details of life. Usually, a small amount of meals should be taken. After the meal, the knee chest position is half an hour, and the abdominal muscles are strengthened. Take small meals and eat more, eat 60% to 70% per meal, suitable for eating soft foods that are easy to digest and have high nutritional value, such as milk, eggs, fish, tender pork, fresh vegetables and fruits. Avoid strong foods such as strong tea and pepper, and eat less overheated, too sweet, too cold foods and tobacco and alcohol.

Complications of superior mesenteric artery syndrome Complications, acute gastric dilatation, nausea and vomiting

Acute gastric dilatation may occur in the clinic. Dehydration, electrolyte imbalance, azotemia and hematocrit may occur when vomiting is severe. Chronic type is often intermittent, and there is no obvious cause of abdominal fullness after eating, accompanied by hernia and vomiting. The amount of vomit is large and contains bile. For a long time, malnutrition, weight loss, etc., and even panic disorder.

Symptoms of superior mesenteric artery syndrome Common symptoms Loss of intestinal stagnation, pain, loss of appetite, abdominal pain

1. Symptoms: The patient has a slow onset and recurrent episodes. The typical manifestation is abdominal pain or cramping after a meal. Sometimes the pain can be located in the right upper abdomen, on the umbilicus or even the back, often 2 to 3 hours after eating, prone position. Or chest and knee position can alleviate and relieve symptoms. Some patients can show pain similar to duodenal ulcer. Due to duodenal stasis and gastric retention, patients often have vomiting. Vomiting occurs after eating, with or without Accompanied by abdominal pain, vomiting is mostly mixed with bile, eating supine position, standing or sitting position is easy to vomit, body position changes, side lying, lying or chest and knee position can alleviate symptoms.

Due to repeated vomiting and loss of appetite, patients can experience weight loss, anemia, malnutrition, water and electrolytes and acid-base balance disorders, and more with emotional changes.

2. Signs: At the time of attack, the stomach is visible in the upper abdomen, peristaltic waves and vibrating water can touch the dilated duodenum.

Examination of superior mesenteric artery syndrome

Generally, there is no specificity. If you can't eat normally for a long time, you may have anemia, abnormal protein and other abnormal test indicators.

1. X-ray barium meal examination: X-ray barium meal examination showed that the duodenum was compressed at the horizontal level, and the expectorant was delayed or even linearly interrupted; the proximal duodenal intestine was obviously dilated, and in some patients, compression was also observed. The penile movement of the end-intestinal tube is enhanced by the reverse peristalsis; when the prone position is taken, the pressure can be relieved, the expectorant passes smoothly, and the proximal expansion disappears.

2. Angiography: Superior mesenteric artery angiography can show the relationship between the superior mesenteric artery and the aortic anatomy. Usually the angle between the superior mesenteric artery and the aorta is less than 25°.

Diagnosis and differentiation of superior mesenteric artery syndrome

diagnosis

Typical symptoms plus a characteristic X-ray barium meal are easier to diagnose.

Differential diagnosis

1. Peptic ulcer: abdominal pain, vomiting and dyspepsia need to be differentiated from peptic ulcer, especially when accompanied by pyloric obstruction, manifested as gastric retention, the main clinical symptoms are vomiting, vomit often more than 12h undigested The food residue is sour and odorous, but it does not contain bile.

2. Duodenal tumors: pancreatic head cancer or giant pancreatic cyst compression can cause duodenal deposition, abdominal ultrasound, CT, endoscopy and retrograde cholangiopancreatography (ERCP) or magnetic resonance cholangiopancreatography Surgery (MRCP) can be distinguished, and even the abdominal aortic aneurysm can be used to compress the duodenum.

3. Others: The disease needs to be distinguished from the duodenal obstruction caused by stones in the duodenum, hairy feces, mites, and foreign bodies.

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