This document provides information about Superior Mesenteric Artery Syndrome, including its anatomy, risk factors, clinical manifestations, diagnosis, treatment, and controversies. It is a rare condition where the third part of the duodenum is compressed between the abdominal aorta and superior mesenteric artery, causing duodenal obstruction. Key symptoms include early satiety, postprandial pain, and vomiting. Diagnosis involves imaging showing an aortomesenteric angle of less than 20 degrees. Treatment options include correcting fluid/electrolyte imbalances, decompression with a nasogastric tube, nutrition support, prokinetic medications, and surgical procedures like duodenal mobilization or bypass.

1. Superior Mesenteric Artery
Syndrome
Abhilash

2. • Von Rokitansky 1861.
• Wilkie 1927.
• 1960s – evidence to support the existence of
the syndrome
• Incidence 0.1-0.3%.
• More common in 10-30 years of age.
• F>M
• Only around 330 case reports in literature.

3. Also called…
• Cast Syndrome
• Wilkie Syndrome
• Arteriomesenteric Duodenal Obstruction
• Chronic Duodenal Ileus

4. Anatomy
• Third portion of duodenum passes between the
aorta and SMA around L3.
• Suspended in position by the ligament of Treitz
• Typical angle created by these 2 vessels is 45-60
degrees. This angle is maintained by the mesenteric
“fat pad”
• In SMA Syndrome this angle can be reduced to < 10%

8. Risk Factors for developing SMA
Syndrome
• Significant weight loss
– Malignancy
– Malabsorptive syndromes
– Anorexia nervosa
– Trauma
– Wasting diseases
• HIV, CHF, burns

9. Risk Factors for developing SMA
Syndrome
• Surgical correction of scoliosis
• Congenitally short ligament of Treitz
• Sudden gain in height.
• Exaggerated lumbar lordosis.
• RARE CASE REPORTS.
– Pregnancy-gravid uterus reduces abdominal volume
– Retroperitoneal hematoma following aneurysm repair
– Prolonged bedrest
– Strongyloides stercoralis infection.
– Hyperthyroidism

10. • Non- vascular theories for compression of 3rd
part of duodenum.
– Duodenal malrotation.
– Inflammatory thickening of mesenteric root
secondary to acute pancreatitis.
– Duodenal ulcer.
– Bowel infarction.

11. Clinical Manifestations
• Symptoms are consistent with small bowel
obstruction
• Early Satiety
• Postprandial epigastric pain
• Nausea/Vomiting
• Vomiting – bilious/partially digested.
• May have distension, high pitched bowel sounds
• Symptoms may be relieved by lying prone or on left
side

12. Complications
• Electrolyte disturbances
– Hypokalemia, metabolic alkalosis
• Gastric perforation
• Gastric pneumatosis and portal venous gas
• Obstructing duodenal bezoar

13. Differential
• Post-op paralytic ileus
• Duodenal dysmotility syndromes
– Diabetes mellitus
– Collagen vascular disease
– Scleroderma
– Chronic ideopathic intestinal pseudo-obstruction

14. Diagnosis
• Diagnosis of exclusion.
• A formal diagnosis is based on extrinsic
compression on duodenum between SMA and
aorta, a distended duodenum and an
aortomesenteric angle <20.
• Peristalsis should still be present

15. Diagnosis
• KUB: gastric distension, dilation of proximal
duodenum
• UGI: dilated stomach and proximal duodenum with
retention of contrast, marked delay in passage of
contrast from duodenum to distal small bowel
• CT/MRI: similar to UGI but also provides info about
intra-abdominal fat concentration and other intra-
abdominal pathology
• SMA arteriography: narrowing of the angle between
SMA and aorta

19. Treatment
• Correction of fluid and electrolyte imbalance
• Decompression via NG tube
• Nutrition
– Orally
– NJ feeds
– TPN
• Metoclopramide iv

20. Surgical options
• Duodenal mobilization and repositioning
• Gastro-jejunostomy
• Duodenojejunostomy

24. Controversy
• Symptoms do not always correlate with
radiography
• Follow up of 16 patients post op for SMA
syndrome at 7 years showed correction of
weight loss, decrease in vomiting but
persistence of nausea, early satiety, fullness

25. References
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Surg. 2007;24(3):149-56. Epub 2007 Apr 27.
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isn’t or is it? J Clin Gastroenterol 1985; 7(2):113-116.
4. A. R. Ahmed and I. Taylor. Postgrad Med J 1997 73: 776-778
5. Matheus et al. Syndrome of Duodenal Compression by the Superior Mesenteric Artery
Following Restorative Proctocolectomy: A Case Report and Review of Literature. Sao Paulo
Med J 2005;123(3):151-3.
6. Simon M, Lemer MA. Duodenal compression by the mesenteric root in acute pancreatitis and
inflammatory conditions of the bowel. Radiology 1962; 79: 75-80.
7. Ylinen P, Kinnunen J, Hockerstedt K. Superior Mesenteric Artery Syndrome. A Follow-up Study
of 16 Operated Patients. J Clin Gastroenterol 1989; 11(4) 386-391.