Aneurysm of superior mesenteric artery: Identification with ultrasonography

Abstract

A true aneurysm is an abnormal widening of a blood vessel that involves all three layers of vessel wall. The basic defect is destruction of elastic fibers in the media, which permits the remaining fibrous tissue to stretch and leads to an increase in diameter. Aneurysms are fusiform with a segment of the vessel becoming diffusely dilated, its total circumference being involved. In contrast, saccular aneurysms affect a portion of the circumference and consist of an outpouching with a mouth.The most common underlying cause is arteriosclerosis, but cystic medial necrosis, trauma, and syphylis and other infections must also be considered as a cause.' The case reported here underlines the importance of ultrasound identification of the lesion. CASE REPORTA 17-year-old young man was seen because of severe abdominal pain of sudden onset. The pain was constant and spread over the whole abdomen. His past history was positive for such pain, but less severe and without correlation to meals. He practiced karate but didn't mention recent abdominal trauma.Physical examination revealed a well developed, well nourished young man with thin skin. The sclera was slightly bluish. No lymphadenopathy was found. There was a round, mobile (partially) and pulsatile abdominal mass at the left epigastrium. Liver and spleen were not palpated. Hyperextensibility of the first metacarpophalangeal joint was noted, which was mentioned to have existed from childhood. Laboratory tests were all at normal range. Plain abdominal X-ray showed no abnormality.An abdominal ultrasonography was performed. The scanner used was EUB-40 ultrasound imaging system (Hitachi, Japan). The transducer was a 3.5 MHZ, convex type.Two dimensional B-mode images were obtained using standard planes and rules. The liver, gall bladder, biliary duct, and pancreas were all normal. The spleen was not enlarged. Evaluation of the retroperitoneal area revealed a well-defined, ovoid, echo-free lesion (27 mm long, 10 to 15 mm wide) adjacent t o the aorta ( Figure 1). The sagital view showed that it was a fusiform dilatation of the superior mesenteric artery (Figure 2). A selective superior mesenteric arteriogram (Figure 3) proved the diagnosis of an SMA aneurysm.

Diagnosis and Management of Aneurysms Involving the Superior Mesenteric Artery and Its Branches

“…It is not uncommon for presenting signs and symptoms to be mistaken for much more common conditions such as pancreatitis, perforated viscus, ulcer disease, or appendicitis.20'23'24 Many SMAAs will reveal rims of calcifications on plain radiographs as demonstrated by case 4.25 Duplex ultrasound imaging has been shown by many to be valuable as a quick and reliable tool for diagnosis. 26 The mycotic aneurysm in case 1 was initially discovered in this fashion. However, as with cases 2 and 3, most SMAAs are currently being diagnosed preoperatively via abdominal computed tomography or angiography (Table III).…”

The Society for Vascular Surgery clinical practice guidelines on the management of visceral aneurysms

“…Symptomatic SMAA presents with similar symptoms as other acute abdominal emergencies, such as perforated viscus, making the diagnosis difficult without an appropriate level of suspicion. 163 Although many SMAAs show a rim of calcification on plain kidney, ureter, and bladder radiography 164 and duplex ultrasound can be helpful in diagnosis, 165 CTA is the most expeditious and reliable diagnostic tool. 166 Isolated superior mesenteric artery dissection has been diagnosed more routinely because of an increase in use of CTA for patients who present with abdominal pain.…”

Ruptured superior mesenteric artery aneurysms during treatment of tetanus: a case report

“…Immediately, ultrasonography showed massive intraperitoneal hematoma. In previous reports, ultrasonography was important in identifying the SMA aneurysm itself [4][5][6]. However, the aneurysms themselves were too small to be detected by ultrasonography in this case.…”