Superior mesenteric artery (SMA) syndrome was first described by Professor Rokitansky in 1842 [
We reviewed our records to identify cases of SMA syndrome, diagnosed in our hospital, a 609-bed tertiary referral hospital, serving a population of 1 million individuals, in the period from October 1995 to January 2012. Patients’ files were retrieved and data were collected which included patients’ demographics, their clinical presentation, how the diagnosis was substantiated, the treatment offered, and the response to treatment.
In this period, we were able to retrieve the files of seven patients, one male and six females, with a mean age of 17.1 years (range 9–25, SD 5.3).
All patients had vomiting and all of them had abdominal pain which was acute in three cases and chronic in the other four. Weight loss was spontaneous in five patients and it followed a weight reduction program in one, while in the seventh patient no history of weight loss was obtained. Associated comorbidities were present in two patients, one with tuberculous interstitial nephritis and another with traumatic paraplegia, while the rest had no comorbidities.
Out of the 7 patients, only three underwent upper endoscopy and in none of them was it diagnostic.
The diagnosis was not suspected on clinical grounds. Rather, it was revealed after radiological investigations performed to explore the patients’ complaints. This took the form of gastrografin/barium meal only in four patients (Figure
(a) and (b) Dilation of the duodenum with abrupt cut-off at its third part, coinciding with the line of the SMA (red line).
Narrow aortomesenteric angle (10°) and aortomesenteric distance (6 mm) (red circles in (a) and (b), resp.), compressing the duodenum in between.
Four patients responded to medical treatment, the essential elements of which were initial gastroduodenal decompression through a nasogastric tube, followed by nutritional support with total parenteral nutrition (TPN) or, if tolerated, small frequent oral meals, aided by positioning of the patient in the right recumbent or prone positions to relieve the compressed duodenum. In the remaining three, surgery was performed. In two patients, it was the primary treatment in the form of side to side duodenojejunostomy, while in the third patient, it followed unresponsiveness to medical treatment and took the form of laparoscopic dissection of the ligament of Treitz.
All patients improved with no further admissions with the same complaints except one patient who received primary duodenojejunostomy, in whom vomiting recurred and was admitted several times with left iliac fossa pain with no obvious reason despite repeated investigations, including a psychiatric evaluation. The clinical and radiological features of the patients as well as the treatment given are shown in Tables
Clinical, radiological, and endoscopic features of individual patients in the series.
Patient | Age (years)/ |
Clinical presentation | Diagnosis on gastrografin/ |
Diagnosis on |
Upper endoscopy |
---|---|---|---|---|---|
1st | 17/♀ | Chronic abdominal pain, vomiting, and weight loss | Yes | Not done | Done, not diagnostic |
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2nd | 16/♀ | Chronic abdominal pain, nausea, repeated vomiting, persistent hunger, and weight loss | Yes | Yes | Done, not diagnostic |
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3rd | 18/♀ | Acute abdominal pain, vomiting, and weight loss | Yes | Not done | Not done |
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4th | 25/♂ | Acute abdominal pain, vomiting, sense of distension, and weight loss | Yes | Yes | Done, not diagnostic+ |
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5th | 13/♀ | Chronic abdominal pain after meals, vomiting, and weight loss | Yes | Not done | Not done |
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6th | 9/♀ | Acute abdominal pain, nausea, and repeated vomiting | Yes | Not done | Not done |
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7th | 22/♀ | Chronic abdominal pain, vomiting, and weight loss | Yes | Yes | Not done |
Treatment and its result.
Patient | Treatment | Result |
---|---|---|
1st | Duodenojejunostomy | Recurrence of vomiting |
2nd | Medical treatment | Improved |
3rd | Duodenojejunostomy | Improved |
4th | Medical treatment | Improved |
5th | Laparoscopic dissection of the ligament of Treitz | Improved |
6th | Medical treatment | Improved |
7th | Medical treatment | Improved |
Wilkie described the clinical and pathophysiological characteristics of the syndrome as well as its management approach, in a series of 64 patients [
Clinically, the patient with a predisposing illness presents with features of gastric outlet obstruction. Sense of fullness, postprandial epigastric pain, belching, and vomiting are characteristic features. Radiologically, barium meal and CT scan show dilatation of the stomach and proximal duodenum with an abrupt cut-off across its third part, together with a decreased aortomesenteric distance as well as aortomesenteric angle. These findings, in the proper clinical sitting, virtually establish the diagnosis. Ultrasound (US) has also been used to aid in the diagnosis. The findings include to and fro movements across the duodenum in the supine, left recumbent, and sitting positions, with facilitation of the flow through the jejunum and elongation of the aortomesenteric distance when the patient assumes the right recumbent position [
The syndrome has specific anatomic basis. The SMA takes off from the abdominal aorta at the level of the first lumbar vertebra with an average angle of 42.4° (range 18° to 70°) and a distance of 10–28 mm. Suspended by the ligament of Treitz, which is attached to its 4th part or to its junction with the jejunum, the duodenum crosses the abdomen at the level of the third lumbar vertebra [
(a) and (b) Wide aortomesenteric angle and distance in a normal individual with no duodenal compression (red circles).
Thinning out of the fat pad between SMA and aorta, consequently upon weight loss, narrows the aortomesenteric angle and distance, thereby compressing the duodenum and thus producing the clinical manifestations of the syndrome. Other contributory factors include an abnormally low origin of SMA, excessive lumbar lordosis, and hypertrophied or shortened ligament of Treitz or its multiple attachments to the duodenum [
When performed, endoscopy may reveal narrowing of the 3rd part of the duodenum due to external compression [
As noticed in our series, upper gastrointestinal series utilizing barium or gastrografin will show dilatation of the stomach and duodenum down to the 3rd part, with a sudden cut-off distally, conforming to the anatomical position of the superior mesenteric artery. In addition, CT scan will show the anatomical configuration of the region with the clam-like action of the SMA and aorta across the third part of the duodenum, resulting in the abrupt cut-off. On sagittal reconstruction of the CT images, a narrowed aortomesenteric distance and angle can be easily depicted, substantiating the diagnosis.
Unrelieved, duodenal perforation may ensue [
Failing appropriate medical treatment, surgical intervention may be considered. The essence is to bypass the site of obstruction by anastomosing the bowel below the bowel above it, thus resuming the functional integrity of the bowel. This may take the form of gastrojejunostomy or duodenojejunostomy, by the open [
Other pathological conditions with similar clinical presentation, including diabetic gastroparesis, scleroderma with duodenal involvement [
The apparent rarity of SMA syndrome may reflect its true rare nature or, alternatively, unawareness of its existence. Published articles are mainly case reports and, rarely, small case series. This limits our understanding of the disease. Keeping a high index of suspension, followed by the utilization of appropriate radiology, may bring more cases to light.
SMA syndrome is a rarely diagnosed condition. Keeping a high index of suspicion followed by the utilization of appropriate radiology is essential for its diagnosis. Although the clinical manifestations of SMA syndrome are shared with many other disease entities, it has unique radiological as well as endoscopic features, which enable a confident diagnosis to be made. Once diagnosed, conservative treatment with nutritional support and positioning should be tried first. In case of unresponsiveness, surgery may give a lasting cure.
This research has been conducted in accordance with national and international standards of ethics, and the approval of the medical research ethics committee has been granted before conducting the study.
The authors of this paper have no conflict of interests to declare and did not receive funding for this research project.