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Findings: On the upper GI, the stomach fills with barium and empties into dilated first and second portions of the duodenum. Barium is seen in the proximal c-loop. There is partial moderate to high grade obstruction in the third portion of the duodenum. Barium eventually passes into normal-appearing jejunal loops.

Differential Diagnosis: A differential diagnosis must include Ladd bands and focal ileus or functional obstruction of the proximal jejunum.

Diagnosis: SMA Syndrome

Discussion: The superior meseteric artery (SMA) syndrome is a condition in which the third portion of the duodenum is trapped between the superior mesentertc artery and the root of the mesentery. It is usually described following either an illness or voluntary dieting. The patients subsequently develop weight loss and vomiting. Plain films may show gastric dilation, but the stomach may be decompressed by vomiting. Barium studies usually shows a partial obstruction of the third portion of the duodenum. Fluoroscopy may demonstrate to and fro motion of the barium in the dilated proximal portions of the duodenum.

The cast syndrome is a form of SMA Syndrome which was initially identified in children who were casted for scoliosis. Subsequently this syndrome has been seen following the placement of rods to correct scoliosis. The straightening of the spine changed the angle at which the SMA leaves the aorta. This causes duodenal compression. Massive gastric dilation is usually seen in this syndrome. Treatment is usually with nasogastric tube decompression.

References:
1) Caffey's Pediatric X-ray Diagnosis. An Integrated Imaging Approach. 9th
edition. G. V. Mosby co. . 1993.

2. Nelson's Essentials of Pediatrics. W.B. Saunders Co.. 1990.

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