Superior mesenteric artery syndrome and anaesthesia

Abstract

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 SMA, resulting in chronic, intermittent, or acute complete or partial duodenal obstruction. SMA syndrome was first described in 1861 by Von Rokitansky. The SMA 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 SMA, coursing between the SMA 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 SMA and aorta, resulting in SMA syndrome. In addition, the aortomesenteric distance in SMA syndrome is decreased to 2-8 mm (normal is 10-20 mm). Alternatively, other causes implicated in SMA syndrome include high insertion of the duodenum at the ligament of Treitz, a low origin of the SMA, and compression of the duodenum due to peritoneal adhesions. 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 [1].