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Superior Mesenteric Artery Syndrome

Shervin Rabizadeh, MD, MBA, Pediatric Gastroenterologist, Cedars Sinai Medical Center; Instructor, Department of Pediatrics, University of California, Los Angeles, David Geffen School of Medicine

Updated: Jun 18, 2009

Introduction

Background

Superior mesenteric artery (SMA) syndrome is an uncommon but well recognized clinical entity characterized by compression of the third, or transverse, portion of the duodenum against the aorta by the superior mesenteric artery, resulting in chronic, intermittent, or acute complete or partial duodenal obstruction.1 Superior mesenteric artery syndrome was first described in 1861 by Von Rokitansky, who proposed that its cause was obstruction of the third part of the duodenum as a result of arteriomesenteric compression.

Despite the fact that about 400 cases are described in the English language literature, many have doubted the existence of superior mesenteric artery syndrome as a real entity; indeed, some investigators have suggested that superior mesenteric artery syndrome is overdiagnosed because it is confused with other causes of megaduodenum. Nonetheless, the entity (also called cast syndrome) is a well-known complication of scoliosis surgery and often poses a diagnostic dilemma; its diagnosis is frequently one of exclusion.

Pathophysiology

The superior mesenteric artery usually forms an angle of approximately 45° (range, 38-56°) with the abdominal aorta, and the third part of the duodenum crosses caudal to the origin of the superior mesenteric artery, coursing between the superior mesenteric artery and aorta. Any factor that sharply narrows the aortomesenteric angle to approximately 6-25° can cause entrapment and compression of the third part of the duodenum as it passes between the superior mesenteric artery and aorta, resulting in superior mesenteric artery syndrome.

In addition, the aortomesenteric distance in superior mesenteric artery syndrome is decreased to 2-8 mm (normal is 10-20 mm). Alternatively, other causes implicated in superior mesenteric artery syndrome include high insertion of the duodenum at the ligament of Treitz, a low origin of the superior mesenteric artery syndrome, and compression of the duodenum due to peritoneal adhesions.2,3

Frequency

United States

The precise incidence of this entity is unknown. In a review of the literature, approximately 0.013-0.3% of the findings from upper GI tract barium studies support a diagnosis of superior mesenteric artery syndrome.

Mortality/Morbidity

Delay in the diagnosis of superior mesenteric artery syndrome can result in malnutrition, dehydration, electrolyte abnormalities, and even death.

Race

No racial differences have been identified.

Sex

More females are affected by superior mesenteric artery syndrome. In one large series of 75 patients with superior mesenteric artery syndrome, two thirds of the cases involved women, with an average age of 41 years; one third of cases involved men, with an average age of 38 years.

Age

The superior mesenteric artery syndrome usually occurs in older children and adolescents. In one report, 75% of the cases occurred in patients aged 10-30 years.

Clinical

History

The patient often presents with chronic upper abdominal symptoms such as epigastric pain, nausea, eructation, voluminous vomiting (bilious or partially digested food), postprandial discomfort, early satiety, and sometimes, subacute small bowel obstruction. Symptoms of superior mesenteric artery (SMA) syndrome often develop from 6-12 days after scoliosis surgery.

The symptoms are typically relieved when the patient is in the left lateral decubitus, prone, or knee-to-chest position, and they are often aggravated when the patient is in the supine position.

Physical

An asthenic habitus is noted in about 80% of cases. Abdominal examination may reveal a succussion splash. Peptic ulcer disease has been noted in 25-45% of the patients, and hyperchlorhydria has been noted in 50%. Patients can present with signs of subacute small bowel obstruction.

Causes

Important etiologic factors that may precipitate narrowing of the aortomesenteric angle and recurrent mechanical obstruction include the following:

  • Constitutional factors
    • Thin body build
    • Exaggerated lumbar lordosis
    • Visceroptosis and abdominal wall laxity
    • Depletion of the mesenteric fat caused by rapid severe weight loss due to catabolic states such as cancer, surgery, burns, or psychiatric problems
  • Severe injuries, such as head trauma, leading to prolonged bedrest
  • Dietary disorders
    • Anorexia nervosa
    • Malabsorption
  • Spinal disease, deformity, or trauma: Use of body cast in the surgical treatment of scoliosis or vertebral fractures. Superior mesenteric artery syndrome cases after corrective spine surgery are due to the result of spinal elongation, which decreases the superior mesenteric/aortic angle. Postoperative weight loss is an important factor for development of superior mesenteric artery syndrome. Although use of Harrington rods for corrective surgery commonly used in the 1950s and 1960s was an important contributory factor for development of superior mesenteric artery syndrome, newer derotation/translation corrective techniques can also rarely be associated with this disease entity.4
  • Rapid linear growth without compensatory weight gain, particularly in adolescents
  • Anatomic anomalies, rarely
    • Abnormally high and fixed position of the ligament of Treitz with an upward displacement of the duodenum
    • Unusually low origin of the superior mesenteric artery
  • Unusual causes
    • Traumatic aneurysm of the superior mesenteric artery after a stab wound
    • Familial superior mesenteric artery syndrome
    • Recurrent superior mesenteric artery syndrome

Differential Diagnoses

Other Problems to Be Considered

The differential diagnosis includes anorexia nervosa and bulimia. In addition, superior mesenteric artery (SMA) syndrome should be differentiated from other causes of megaduodenum, including diabetes mellitus, collagen vascular conditions, and chronic idiopathic intestinal pseudoobstruction.

Workup

Imaging Studies

  • The diagnosis of superior mesenteric artery (SMA) syndrome is difficult. Confirmation usually requires radiographic studies, such as an upper GI series, hypotonic duodenography, and CT scanning.
  • Upper GI study with barium reveals characteristic dilatation of the first and second parts of the duodenum, with an abrupt vertical or linear cutoff in the third part with normal mucosal folds.
  • Fluoroscopy demonstrates a to-and-fro motion of the barium in the dilated proximal portion of the duodenum. Other findings include delay of 4-6 hours in gastroduodenal transit and relief of the obstruction when the patient is in the left lateral decubitus position.
  • A Hayes maneuver (ie, pressure applied below the umbilicus in cephalad and dorsal direction), which elevates the root of small-bowel mesentery, may also relieve the obstruction.
  • In equivocal cases, hypotonic duodenography may depict the site of obstruction and dilation of the proximal duodenum, with antiperistaltic waves within the dilated portion.
  • CT scanning is useful in the diagnosis of superior mesenteric artery syndrome and can provide diagnostic information, including aorta-superior mesenteric artery distances and duodenal distension. Also, it can be used to assess intra-abdominal and retroperitoneal fat.
  • Upper GI endoscopy may be necessary to exclude mechanical causes of duodenal obstruction. However, the diagnosis of superior mesenteric artery syndrome may be missed with this study.
  • Abdominal ultrasonography may be helpful in measuring the angle of the superior mesenteric artery and the aortomesenteric distance.
  • Manometry may be used to differentiate between the possibility of a myopathic form of chronic intestinal pseudo-obstruction syndrome (hollow visceral myopathy) by demonstrating low-amplitude waves throughout the duodenum, and frequently the stomach, versus an irregular or absent phase III and no postprandial motility changes in a neuropathic form of chronic intestinal pseudoobstruction syndrome. The pattern of increased amplitude of propagated contractions and retrograde contractions should hint or suggest the mechanical obstruction in superior mesenteric artery syndrome.

Treatment

Medical Care

Reversing or removing the precipitating factor is usually successful in a patient with acute superior mesenteric artery (SMA) syndrome. Conservative initial treatment is recommended in all patients with superior mesenteric artery syndrome; this includes adequate nutrition, nasogastric decompression, and proper positioning of the patient after eating (ie, left lateral decubitus, prone, or knee-to-chest position). Enteral feeding using a double lumen nasojejunal tube passed distal to the obstruction under fluoroscopic assistance is an effective adjunct in treatment of patients with rapid severe weight loss and also eliminates the need for intravenous fluids and the risks associated with total parenteral nutrition.

In some instances, both enteral and parenteral nutritional support may be needed to provide optimal calories. The patient's weight should be monitored daily. Subsequently, the patient can be started on oral liquids followed by slow and gradual introduction of small and frequent soft meals as tolerated. Finally, regular solid foods are introduced. Metoclopramide treatment may be beneficial. Review of the orthopedic literature reveals that the success rate is 100% with medical management only in cases with an acute presentation of superior mesenteric artery syndrome.

Surgical Care

Surgical intervention is indicated when conservative measures are ineffective, particularly in patients with a long history of progressive weight loss, pronounced duodenal dilatation with stasis, and complicating peptic ulcer disease. Duodenojejunostomy is the most frequently used procedure, and it is successful in about 90% of cases.5,6 The use of laparoscopic surgery that involves lysis of the ligament of Treitz and mobilization of the duodenum has been reported.

Consultations

The following consultations may be indicated:

  • Pediatric gastroenterologist
  • Nutritionist
  • Pediatric surgeon

Diet

Medical therapy usually begins with the initiation of intravenous fluids, with the frequent administration of small amounts of liquids. In some cases, nasogastric tube feedings with a standard liquid diet may be indicated.

Medication

Drug therapy currently is not a component of the standard of care for this syndrome. Metoclopramide may be used to provide a prokinetic effect.

Prokinetic agents

These stimulate motility of the GI tract. GI smooth muscle is regulated by autonomic innervation, local reflexes, and hormones. Peristalsis is induced and causes the gut contents to move, encouraging digestion.


Metoclopramide (Reglan, Clopra)

Dopamine antagonist that stimulates acetylcholine release in the myenteric plexus. Acts centrally on chemoreceptor triggers in the floor of the fourth ventricle, causing important antiemetic activity.

Dosing

Adult

5-10 mg PO ac and hs

Pediatric

6-14 years: 0.1-0.2 mg/kg PO qd/bid/tid/qid; not to exceed 0.5 mg/kg/d
>14 years: Administer as in adults

Interactions

Anticholinergic agents may antagonize effects of metoclopramide; opiate analgesics may increase toxicity in the CNS

Contraindications

Documented hypersensitivity; pheochromocytoma; GI hemorrhage, obstruction, or perforation; history of seizure disorders; coadministration of drugs likely to cause extrapyramidal symptoms

Precautions

Pregnancy

B - Usually safe but benefits must outweigh the risks.

Precautions

Caution in renal impairment (decrease dose), hypertension, and depression

Follow-up

Further Outpatient Care

  • Nasogastric tube feedings with a standard liquid diet may be indicated in some patients.
  • These feedings may be continued at home until the obstruction resolves spontaneously.

Complications

  • Electrolyte imbalance (eg, hypokalemia)
  • Dehydration
  • Malnutrition
  • Oliguria

Prognosis

  • The outcome is excellent if the entity is diagnosed in a timely fashion and if the patient receives appropriate therapy.
  • In the past, deaths due to progressive dehydration, hypokalemia, and oliguria have been reported; most of these occurred in patients in whom the diagnosis was delayed or missed.

Miscellaneous

Medicolegal Pitfalls

  • Failure to diagnose superior mesenteric artery (SMA) syndrome can lead increased morbidity and even death, resulting in medicolegal pitfalls and potential litigation.

References

  1. Gerasimidis T, George F. Superior Mesenteric Artery Syndrome. Wilkie Syndrome. Dig Surg. May 20 2009;26(3):213-214. [Medline].

  2. Merrett ND, Wilson RB, Cosman P, Biankin AV. Superior mesenteric artery syndrome: diagnosis and treatment strategies. J Gastrointest Surg. Feb 2009;13(2):287-92. [Medline].

  3. Kyslan K, Barla J, Kyslan K, Stanislayova M. [Superior mesenteric artery (SMAS/AMS) syndrome and its management]. Rozhl Chir. May 2008;87(5):255-8. [Medline].

  4. Ha CD, Alvear DT, Leber DC. Duodenal derotation as an effective treatment of superior mesenteric artery syndrome: a thirty-three year experience. Am Surg. Jul 2008;74(7):644-53. [Medline].

  5. Morris TC, Devitt PG, Thompson SK. Laparoscopic Duodenojejunostomy for Superior Mesenteric Artery Syndrome-How I Do It. J Gastrointest Surg. Apr 9 2009;[Medline].

  6. Jo JB, Song KY, Park CH. Laparoscopic duodenojejunostomy for superior mesenteric artery syndrome: report of a case. Surg Laparosc Endosc Percutan Tech. Apr 2008;18(2):213-5. [Medline].

  7. Altiok H, Lubicky JP, DeWald CJ, Herman JE. The superior mesenteric artery syndrome in patients with spinal deformity. Spine. Oct 1 2005;30(19):2164-70. [Medline].

  8. Altman DH, Puranik SR. Superior mesenteric artery syndrome in children. Am J Roentgenol Radium Ther Nucl Med. May 1973;118(1):104-8. [Medline].

  9. Baltazar U, Dunn J, Floresguerra C. Superior mesenteric artery syndrome: an uncommon cause of intestinal obstruction. South Med J. Jun 2000;93(6):606-8. [Medline].

  10. Barnes JB, Lee M. Superior mesenteric artery syndrome in an intravenous drug abuser after rapid weight loss. South Med J. Mar 1996;89(3):331-4. [Medline].

  11. Crowther MAA, Webb PJ, Eyre-Brook IA. Superior mesenteric artery syndrome following surgery for scoliosis. Spine. 2002;27:E528-33.

  12. Hutchinson DT, Bassett GS. Superior mesenteric artery syndrome in pediatric orthopedic patients. Clin Orthop. Jan 1990;(250):250-7. [Medline].

  13. Massoud WZ. Laparoscopic management of superior mesenteric artery syndrome. Int Surg. Oct-Dec 1995;80(4):322-7. [Medline].

  14. Munns SW, Morrissy RT, Golladay ES. Hyperalimentation for superior mesenteric-artery (cast) syndrome following correction of spinal deformity. J Bone Joint Surg Am. Oct 1984;66(8):1175-7. [Medline].

  15. Ortiz C, Cleveland RH, Blickman JG. Familial superior mesenteric artery syndrome. Pediatr Radiol. 1990;20(8):588-9. [Medline].

  16. Raissi B, Taylor BM, Taves DH. Recurrent superior mesenteric artery (Wilkie's) syndrome: a case report. Can J Surg. Oct 1996;39(5):410-6. [Medline].

  17. Rokitansky C. Handbuch der Pathologischen Anotomie. Vienna: Branmiller and Siedel. 1842.

  18. Santer R, Young C, Rossi T. Computed tomography in superior mesenteric artery syndrome. Pediatr Radiol. 1991;21(2):154-5. [Medline].

  19. Shah MA, Albright MB, Vogt MT, Moreland MS. Superior mesenteric artery syndrome in scoliosis surgery: weight percentile for height as an indicator of risk. J Pediatr Orthop. Sep-Oct 2003;23(5):665-8. [Medline].

  20. Shapiro G, Green DW, Fatica NS, Boachie-Adjei O. Medical complications in scoliosis surgery. Curr Opin Pediatr. Feb 2001;13(1):36-41. [Medline].

  21. Shetty AK, Schmidt-Sommerfeld E, Haymon ML. Radiological case of the month. Superior mesenteric artery syndrome. Arch Pediatr Adolesc Med. Mar 1999;153(3):303-4. [Medline].

  22. Vitale MG, Higgs GB, Liebling MS, et al. Superior mesenteric artery syndrome after segmental instrumentation: a biomechanical analysis. Am J Orthop. Aug 1999;28(8):461-7. [Medline].

  23. Wilkie DPD. Chronic duodenal ileus. Am J Med Sci. 1927;173:643-9.

  24. Ylinen P, Kinnunen J, Hockerstedt K. Superior mesenteric artery syndrome. A follow-up study of 16 operated patients. J Clin Gastroenterol. Aug 1989;11(4):386-91. [Medline].

Keywords

superior mesenteric artery syndrome, SMA syndrome, cast syndrome, Wilkie's syndrome, Wilkie syndrome, arteriomesenteric duodenal compression syndrome, chronic duodenal ileus, scoliosis, megaduodenum, small bowel obstruction, peptic ulcer disease, diagnosis, treatment

Contributor Information and Disclosures

Author

Shervin Rabizadeh, MD, MBA, Pediatric Gastroenterologist, Cedars Sinai Medical Center; Instructor, Department of Pediatrics, University of California, Los Angeles, David Geffen School of Medicine
Shervin Rabizadeh, MD, MBA is a member of the following medical societies: American Academy of Pediatrics, American Gastroenterological Association, and North American Society for Pediatric Gastroenterology, Hepatology and Nutrition
Disclosure: Nothing to disclose.

Medical Editor

Jorge H Vargas, MD, Professor of Pediatrics and Clinical Professor of Pediatric Gastroenterology, David Geffen School of Medicine, University of California at Los Angeles; Consulting Physician, Department of Pediatrics, University of California at Los Angeles Health System
Jorge H Vargas, MD is a member of the following medical societies: American Liver Foundation, American Society for Gastrointestinal Endoscopy, American Society for Parenteral and Enteral Nutrition, Latin American Society of Pediatric Gastroenterology, Hepatology & Nutrition, and North American Society for Pediatric Gastroenterology and Nutrition
Disclosure: Nothing to disclose.

Pharmacy Editor

Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Pfizer Inc Stock Investment from financial planner; Avanir Pharma Stock Investment from financial planner ; WebMD Salary and stock Employment and investment from financial planner

Managing Editor

B UK Li, MD, Professor of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Director, Pediatric Fellowships and Gastroenterology Fellowship, Medical Director, Functional Gastrointestinal Disorders and Cyclic Vomiting Program, Medical College of Wisconsin; Attending Gastroenterologist, Children's Hospital of Wisconsin
B UK Li, MD is a member of the following medical societies: Alpha Omega Alpha, American Gastroenterological Association, and North American Society for Pediatric Gastroenterology and Nutrition
Disclosure: Nothing to disclose.

CME Editor

Steven M Schwarz, MD, FAAP, FACN, AGAF, Professor of Pediatrics, Children's Hospital at Downstate, SUNY-Downstate Medical Center
Steven M Schwarz, MD, FAAP, FACN, AGAF is a member of the following medical societies: American Academy of Pediatrics, American College of Nutrition, American College of Physician Executives, American Gastroenterological Association, American Pediatric Society, Gastroenterology Research Group, New York Academy of Medicine, North American Society for Pediatric Gastroenterology and Nutrition, and Society for Pediatric Research
Disclosure: TAP Pharmaceuticals Honoraria Speaking and teaching; Curemark, LLC Consulting fee Board membership; Centocor, Inc. Grant/research funds Independent contractor

Chief Editor

Carmen Cuffari, MD, Associate Professor, Department of Pediatrics, Division of Gastroenterology/Nutrition, Johns Hopkins University School of Medicine
Carmen Cuffari, MD is a member of the following medical societies: American College of Gastroenterology, American Gastroenterological Association, North American Society for Pediatric Gastroenterology, Hepatology and Nutrition, and Royal College of Physicians and Surgeons of Canada
Disclosure: Nothing to disclose.

Acknowledgments

The authors and editors of eMedicine gratefully acknowledge the contributions of previous authors Avinash Shetty, MD, and Ivor D Hill, MB, ChB, DCH, FCP, MD, to the original writing and development of this article.

Further Reading

  • Related eMedicine topics include the following:
    • Chronic Mesenteric Ischemia
    • Mesenteric Artery Ischemia

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