Superior mesenteric artery syndrome

 

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SMA Syndrome

SMA syndrome was first described in 1861 by Carl Freiherr von Rokitansky.

Superior mesenteric artery (SMA) syndrome is a rare, potentially life-threatening gastro-vascular disorder characterized by a compression of the third portion of the duodenum by the abdominal aorta (AA) and the overlying superior mesenteric artery. The syndrome is typically caused by an angle of 6°-25° between the AA and the SMA, in comparison to the normal range of 38°-56°, due to a lack of retroperitoneal and visceral fat (mesenteric fat). In addition, the aortomesenteric distance is 2-8 millimeters, as opposed to the typical 10-20.[1] However, a narrow SMA angle alone is not enough to make a diagnosis, because patients with a low BMI, most notably children, have been known to have a narrow SMA angle with no symptoms of SMA syndrome.[2]

SMA syndrome was first described in 1861 by Carl Freiherr von Rokitansky in victims at autopsy, but remained pathologically undefined until 1927 when Wilkie published the first comprehensive series of 75 patients.[3] According to a 1956 study, only .3% of patients referred for an upper-gastrointestinal-tract barium studies fit this diagnosis, making it one of the rarest gastrointestinal disorders known to medical science.[4] Recognition of SMA syndrome as a distinct clinical entity is controversial, due in part to its possible confusion with a number of other conditions,[5] though it is now widely acknowledged.[1]

SMA syndrome is also known as Wilkie's syndrome, cast syndrome, mesenteric root syndrome, chronic duodenal ileus and intermittent arterio-mesenteric occlusion.[6] It is distinct from Nutcracker syndrome, which is the entrapment of the left renal vein between the AA and the SMA, although it is possible to be diagnosed with both conditions.