superior mesenteric artery compression syndrome (SMA)



Overview

  • Disease caused by compression of the superior mesenteric artery at the level of the duodenum.
  • It is often characterized by postprandial epigastric pain, nausea and vomiting.
  • It is often caused by congenital and acquired factors.
  • Mainly conservative and surgical treatments
  • Definition

  • Superior mesenteric artery compression syndrome is a clinical syndrome in which the superior mesenteric artery and its accompanying veins compress the horizontal part of the duodenum due to congenital or acquired factors, causing acute and chronic intestinal obstruction of the duodenum [1][2].
  • Superior mesenteric artery compression syndrome may present with a series of clinical symptoms such as postprandial epigastric distension, nausea, and vomiting.
  • Classification

    Classification according to the urgency of onset

    Acute superior mesenteric artery compression syndrome

    Acute onset, relatively rare, mostly caused by medical factors and exogenous trauma. It presents with severe abdominal pain, epigastric fullness and discomfort, nausea and vomiting [1][3].

    Chronic superior mesenteric artery compression syndrome

    It has a long course and may present with marked wasting, recurrent postprandial epigastric pain, nausea, and vomiting [1][3].

    Morbidity

  • The foreign incidence of superior mesenteric artery compression syndrome is 0.1% to 0.3% [4].
  • There is no information related to the incidence in China.
  • The disease can occur at any age, with 20 to 30 years of age being the most prevalent age [5].
  • There is no significant difference in gender [5].
  • It is mostly seen in long and thin body types.
  • Etiology

    Causes of the disease

    Superior mesenteric artery compression syndrome can be caused by congenital factors as well as acquired factors such as chronic wasting disease, pseudoaneurysm of the superior mesenteric artery, medical and dynamical factors.

    Congenital factors

  • A low separation of the superior mesenteric artery from the abdominal aorta or a small angle between the two can compress the transverse duodenum.
  • A short or high attachment of the ligament of Treitz may cause the duodenum to be positioned too high and compressed at the root of the angle formed by the superior mesenteric artery and the abdominal aorta.
  • The angle between the superior mesenteric artery and the abdominal aorta is narrowed by a kyphotic deformity.
  • Acquired factors

  • Chronic wasting diseases as well as hypermetabolic states: tuberculosis, severe malabsorption disorders, malignant tumors, extensive burns, Crohn’s disease, etc., can lead to significant wasting of the patient and cause duodenal compression.
  • Abdominal aortic aneurysm, pregnancy, trauma resulting in pseudoaneurysm of the superior mesenteric artery, multiple sclerosis and other morphological changes in adjacent tissues can change the gap between the superior mesenteric artery and the aorta, resulting in duodenal compression.
  • Medical factors: such as orthopedic surgery to treat scoliosis and spinal cord injury using plaster bed fixation can lead to morbidity, esophagectomy and other surgical procedures due to change the normal anatomical structure can also lead to morbidity.
  • Dynamic factors: the combination of functional gastrointestinal disease and habitual constipation may cause superior mesenteric artery compression syndrome.
  • Predisposing factors

    The following factors are predisposing factors for superior mesenteric artery compression syndrome and can lead to its onset or exacerbation [6].

  • Excessive pharmacologic weight loss.
  • Psychological factors: emotional agitation.
  • Surgery, anesthesia, prolonged bed rest.
  • Consumption of rotten food, overeating.
  • Pathogenesis

    Various causes lead to changes in the anatomical relationship between the superior mesenteric artery, the abdominal aorta and the duodenum, causing compression of the duodenum, which results in narrowing of the intestinal lumen and obstruction.

    Symptoms

    Superior mesenteric artery compression syndrome has a chronic onset with intermittent, recurrent episodes, and is characterized by symptoms of duodenal obstruction, manifesting as postprandial epigastric pain, nausea, and vomiting.

    Main Symptoms

    Postprandial epigastric pain

  • Postprandial epigastric pain may occur several minutes or 1~3 hours after eating, and it is obvious in supine position.
  • It is mostly vague or distending pain, and can also manifest as severe abdominal cramps.
  • Nausea and vomiting

  • Vomiting is more frequent, the vomit contains bile, and the abdominal pain can be relieved after vomiting.
  • Vomiting: Vomiting often occurs 15 to 40 minutes after eating, the amount of vomiting is large, and the vomit contains bile without fecal odor.
  • Other symptoms

    Wasting

  • Patients with superior mesenteric artery compression syndrome are often afraid to eat for fear of abdominal pain and vomiting after eating.
  • In patients with prolonged recurrent episodes, emaciation and weight loss may occur.
  • Complications

    When superior mesenteric artery compression syndrome is severe, it can be complicated by acute gastric dilatation, upper gastrointestinal hemorrhage, portal vein thrombosis, intestinal necrosis, duodenal perforation and so on.

    Acute gastric dilatation

  • Acute superior mesenteric artery compression syndrome can cause acute gastric dilatation if not treated in time.
  • Patients will have clinical manifestations such as epigastric fullness, vomiting (vomit is gastric contents), thirst, depression, and shortness of breath.
  • Intestinal necrosis

  • Patients with superior mesenteric artery compression syndrome are prone to complications of intestinal stenosis.
  • It manifests as abdominal pain, abdominal distension, nausea, vomiting and other symptoms.
  • Upper gastrointestinal hemorrhage

  • Patients often develop upper gastrointestinal bleeding due to severe vomiting.
  • Symptoms such as vomiting blood, black stools and blood in the stool may be manifested. Excessive blood loss may present with symptoms such as dizziness, palpitations, weakness, and chills in the extremities. Anemia can occur after excessive blood loss.
  • Portal vein thrombosis

  • Untreated superior mesenteric artery compression syndrome may cause portal vein thrombosis.
  • Patients may exhibit symptoms such as abdominal pain, nausea, vomiting, diarrhea, and blood in the stool.
  • Duodenal perforation

  • Untreated superior mesenteric artery compression syndrome may cause duodenal perforation.
  • Patients may exhibit severe abdominal pain that radiates to the back, as well as pallor, chills in the limbs, nausea, and vomiting.
  • Consultation

    Department of Medicine

    General Surgery

    If symptoms such as postprandial epigastric pain, nausea, vomiting and weight loss occur, it is recommended to consult the general surgery department promptly.

    Emergency Department

    In case of severe abdominal pain, vomiting blood, blood in stool and other critical symptoms, it is recommended to consult the Emergency Department or call 120 emergency number immediately.

    Preparation

    Consultation: Registration, Preparation of Documents, Frequently Asked Questions

    Tips for seeking medical treatment

  • Rest and avoid strenuous exercise before seeking medical treatment.
  • For patients with severe symptoms, it is recommended that they be accompanied by their family members.
  • Preparation List

    Symptom list

    Pay particular attention to the time of onset of symptoms, special manifestations, etc.

  • Is there epigastric pain after meals?
  • Is there nausea, vomiting?
  • Is there wasting or weight loss?
  • How long have these symptoms been present?
  • List of medical history
  • Are there any chronic wasting diseases such as malignant tumors, extensive burns, etc.?
  • Has there been an abdominal aortic aneurysm, pseudoaneurysm of the superior mesenteric artery, multiple sclerosis?
  • Has there been pregnancy and trauma?
  • Do you have scoliosis and orthopedic treatment for spinal cord injury?
  • Do you have functional gastrointestinal disease, habitual constipation?
  • Have you been bedridden for a long period of time, have you been on excessive medication to lose weight, etc.?
  • Checklist

    Examination results in the past six months, which can be brought to the doctor’s office.

    Imaging tests: standing abdominal X-ray, upper gastrointestinal X-ray barium contrast, abdominal ultrasound, abdominal CT, abdominal magnetic resonance imaging.

    Diagnosis

    Diagnosis is based on

    Medical history

  • Suffering from malignant tumors, extensive burns, and other chronic wasting diseases.
  • Suffering from abdominal aortic aneurysm, pseudoaneurysm of the superior mesenteric artery, multiple sclerosis.
  • Is pregnant or has had trauma.
  • Orthopedic treatment for scoliosis and spinal cord injury.
  • Functional gastrointestinal disease, constipation.
  • Prolonged bed rest, excessive weight loss through medication, etc.
  • Clinical manifestations

  • Postprandial epigastric pain, nausea, vomiting.
  • May be accompanied by emaciation and weight loss.
  • Imaging

    Static abdominal X-ray, upper gastrointestinal X-ray barium radiography
  • It is difficult to diagnose superior mesenteric artery compression syndrome on standing abdominal radiographs during remission.
  • Barium upper gastrointestinal X-ray is not the first choice because swallowing barium may aggravate the symptoms of intestinal obstruction.
  • Necklaces, belts, and other items should be removed prior to the examination, and metal clothing should be avoided.
  • Ultrasound of the abdomen
  • Ultrasound of the upper mesenteric artery and abdominal aorta.
  • The examination can clearly show the relationship between the superior mesenteric artery and the abdominal aorta, and can initially diagnose superior mesenteric artery compression syndrome.
  • Before the examination, the diet should be light, avoiding high-fat and greasy food, and wearing easy-to-change clothes and shoes.
  • Abdominal CT examination
  • It can confirm the diagnosis of superior mesenteric artery compression syndrome and exclude other diseases.
  • Three-dimensional reconstruction after enhancement can clearly show the three-dimensional structural relationship between the superior mesenteric artery, abdominal aorta and duodenum.
  • Remove any metal objects, such as necklaces and earrings, before the examination.
  • Magnetic Resonance Angiography (MRA)
  • It can clearly show the relationship between the superior mesenteric artery and the abdominal aorta, and is non-invasive and radiation-free.
  • The angle between the superior mesenteric artery and the abdominal aorta can be measured to show duodenal compression.
  • Remove any metal objects, such as necklaces and earrings, from the body before the examination. Be careful to maintain the position during the examination and do not swing freely.
  • Differential Diagnosis

    When epigastric pain, nausea, and vomiting are present and superior mesenteric artery compression syndrome is being considered, care should be taken to differentiate it from the following conditions

    Acute gastric dilatation

  • Similarity: both may present with epigastric pain, nausea and vomiting.
  • Differences
  • Acute gastric dilatation may be characterized by thirst, depression and shortness of breath.
  • It usually occurs after overeating or abdominal surgery, has a shorter history, and the vomit does not contain bile.
  • Blood gas analysis may suggest alkalosis, and gastric dilatation is seen on abdominal ultrasonography, which helps to differentiate it.
  • Congenital megaduodenal disease

  • Similarities: Both may present with epigastric pain, nausea and vomiting.
  • Differences: Congenital megaduodenal disease often occurs in children, X-ray suggests generalized dilatation of the duodenum, lack of peristalsis, no stenotic changes, can not be relieved by changing the patient’s position, which can help to differentiate.
  • Functional dyspepsia

  • Similarities: both can present with epigastric pain, nausea, vomiting and other symptoms.
  • Differences: Functional dyspepsia patients have no obvious abnormal changes on endoscopy, which can help to differentiate them.
  • Treatment

  • Aim of treatment: alleviate symptoms, control disease progression, prevent and reduce complications.
  • Treatment principle: superior mesenteric artery compression syndrome mainly adopts conservative treatment, when conservative treatment fails, intestinal obstruction can not be relieved when the choice of surgical treatment.
  • Conservative treatment

    General treatment

  • Fasting, gastrointestinal decompression, suctioning out a large amount of gastric contents and bile can relieve symptoms[5].
  • Correction of water, electrolyte and acid-base disorders, and those with malnutrition need to be corrected preoperatively, and parenteral nutritional support can be used if necessary [5].
  • Changing position, such as prone position or knee-chest position, and bed rest can relieve symptoms [5].
  • Attention to dietary modification, and some patients can be supplemented with nasojejunal tube feeding [5].
  • Patients with wasting, weakness type body and abdominal wall laxity can apply abdominal bandage to prevent visceral prolapse, and improve nutrition, strengthen abdominal muscle exercise, and correct spinal anteversion [5].
  • Medication

    Antispasmodic drugs
  • Conservative treatment of gastrointestinal symptoms is more serious, antispasmodic drugs can be used.
  • Commonly used drugs: scopolamine.
  • Adverse effects such as dry mouth, red face, blurred vision, and urinary retention may occur with use.
  • Proton pump inhibitors
  • Proton pump inhibitors may also be used to protect the gastric mucosa when vomiting is more severe.
  • Commonly used drugs: Omeprazole.
  • People with impaired liver function should use it with caution, and those who are using clopidogrel need to inform the doctor before treatment.
  • Surgery

    Purpose of Surgery

    The purpose of surgery is to relieve duodenal obstruction, restore intestinal patency, and remove the primary cause of the disease as far as possible.

    Indications

    Surgery is not usually the first choice of treatment, and is only indicated when conservative treatment fails, or when serious complications or tumors occur, in order to restore the smoothness of the gastrointestinal tract.

    Surgical modalities

  • Including duodenojejunostomy, anterior duodenal vascularization, ligament of Treitz release, Billroth II type gastrojejunostomy, gastrectomy, gastrojejunostomy and duodenal loop drainage, laparoscopic surgery.
  • Duodenojejunostomy and Treitz ligament release are the main surgical procedures.
  • Contraindications

    Patients with bleeding tendency, serious cardiovascular disease, poor liver and kidney function.

    Precautions before and after surgery

  • Closely observe the changes of body temperature, pulse, respiration, blood pressure and mental state before and after surgery.
  • After surgery, pay attention to whether the negative pressure drainage tube is fixed and smooth, strengthen nutrition, and pay attention to the care of surgical incision and stoma.
  • After surgery, pay attention to the changes of bowel sounds, pay attention to the time of anal exhaustion.
  • Prognosis

    Cure

  • Untreated can not be self-cured.
  • The prognosis of superior mesenteric artery compression syndrome is relatively good with early and timely detection and conservative treatment.
  • If it is not detected in time, the prognosis is poorer as the disease progresses and more serious complications such as upper gastrointestinal hemorrhage occur.
  • Prognostic factors

  • Early diagnosis and early treatment: If the disease can be diagnosed and treated in time, a better prognosis can often be achieved.
  • Patient’s condition: patients with complications such as upper gastrointestinal hemorrhage and acute gastric dilatation have a poorer prognosis.
  • Harmfulness

  • Impact on normal life: the occurrence of abdominal pain, epigastric fullness and discomfort, nausea, vomiting, etc. may affect daily life.
  • Mental health: Superior mesenteric artery compression syndrome has a long course and patients are prone to depression, anxiety and other adverse emotions.
  • Complications: If superior mesenteric artery compression syndrome is left untreated or untreated in time, complications such as acute gastric dilatation, upper gastrointestinal hemorrhage, portal vein thrombosis, intestinal necrosis and duodenal perforation may occur in severe cases.
  • Daily

    Daily management

    Dietary management

  • Eat regularly, eat small and frequent meals, avoid eating too much at one time and avoid overeating.
  • A light diet is recommended, avoiding stimulating foods such as chili peppers and ginger.
  • It is recommended to eat more vitamin-rich foods, such as spinach and cucumber.
  • Avoid gas-producing foods, such as sweet potatoes, when bloating occurs.
  • Life Management

  • Live a regular life, pay attention to rest and avoid exertion.
  • Keep in a good mood.
  • Follow-up

  • Importance of follow-up: Regular follow-up helps to detect recurrence and aggravation of the disease in time and adjust the treatment plan in time.
  • Follow-up time: It is recommended to follow the doctor’s instructions for follow-up.
  • Examination items to be done during follow-up: upper gastrointestinal X-ray barium contrast, abdominal ultrasonography, abdominal CT examination, abdominal magnetic resonance imaging.
  • Prevention

    Superior mesenteric artery compression syndrome is often secondary to underlying diseases such as chronic wasting disease. The following measures can reduce the occurrence of superior mesenteric artery compression syndrome.

  • Active treatment of chronic wasting disease, pseudoaneurysm of the superior mesenteric artery, and multiple sclerosis can reduce the probability of superior mesenteric artery compression syndrome to some extent.
  • Patients who are bedridden for a long period of time should pay attention to dietary adjustments.
  • It is recommended to eat small meals, each meal should not be too full, and avoid eating rotten food.
  • Prevent constipation, strengthen exercise, and avoid excessive medication for weight loss.
  • After orthopedic surgical treatment for scoliosis and spinal cord injury with cast immobilization, patients are prone to develop superior mesenteric artery compression syndrome.