Superior mesentery artery aneurysm with thrombosis and proximal stenosis in a case with Ehlers–Danlos syndrome

Arterial aneurysms of the major arteries are common in the adult population. However, aneurysms involving the visceral arteries are rare with an incidence of 0.01% [1],[2]. Superior mesenteric artery (SMA) related aneurysms constitute a small portion of the visceral aneurysms and have a mortality rate up to 35% [3]. Visceral arterial aneurysms are very rare in the pediatric patient population and might be associated with connective tissue disorders [4]. In this report, we present a peculiar case with SMA aneurysm, distal partial thrombosis and proximal stenosis in a 14 years old male detected by computed tomography angiography (CTA).

A 14-year-old patient presented to the emergency department complaining of sudden onset of cramping abdominal pain around the navel and deterioration in general condition 6 hours prior. He had a previous scoliosis operation at the age of 10 and diagnosis of Ehlers–Danlos type IV disease. On initial examination, the skin was moist and pale, blood pressure was hypotensive at 85/45 mmHg, pulse was 125 indicating tachycardia, and respiratory rate was 24 indicating tachypnea. Abdominal examination showed tenderness and rebound. Abdominal ultrasound showed collection of fluid in the peritoneal cavity and an abnormal dilated vessel anterior to the aorta. Doppler examination showed vascular color-coding consistent with vascular filling in the abnormal dilated vessel. The patient was erred to the CT unit for the detailed evaluation of abdominal circulation by contrast-enhanced CTA. On CT images, a proximal stenotic segment and aneurysm of the SMA was detected (Figure 1A and Figure 1B). A partial thrombus was detected distal to the dilated segment (Figure 2A). More caudal images showed intraperitoneal fluid and hypoperfusion of ileal and jejunal loops (Figure 2B). The patient underwent laparotomy in which subtotal intestinal ischemia was detected. The patient deceased in post-operative intensive care unit due to generalized intestinal infarct at 24 hours after admission to ER.

Our case had proximally orientated SMA aneurysm and the distal thrombus which were concluded with fatal intestinal ischemia. Our case also had a stenotic segment proximal to the aneurysm. The formation of visceral aneurysms distal to the stenotic segment has been associated with high and low wall shear stress theories. These theories may explain the pathophysiology of the visceral aneurysm that formed distal to the stenotic segment in our case [5].

Pediatric non-aortic arterial aneurysms are extremely uncommon. Several factors such as infection, trauma, connective tissue diseases, noninfectious arteritis, or congenital vascular malformations are responsible for the development of aneurysm in the child population [6]. Aneurysms involving the visceral arteries are extremely rare in the pediatric population. These aneurysms can be due to fungal or bacterial infection, noninfectious inflammatory disease, or connective tissue disorders [7],[8]. Except for connective tissue related syndromes such as Ehlers–Danlos type IV disease, surgical repair is the main treatment option. However, in cases with Ehlers–Danlos syndromes, surgery is not perable due to fragility of the vessels and ligation of the dilated vessel is advised [7],[9].

Our patient had a history of scoliosis operation and diagnosed with Ehlers–Danlos syndrome. Furthermore, the patient had a pre-aneurysmal stenotic segment and thrombosis in the distal segment of the aneurysm. Detection of thrombosis was important as it determined the fate of our patient. Thrombosis of the celiac axis was reported in another case who had type IV Ehlers–Danlos and underwent an operation of correction of scoliosis. In that case, authors associated the thrombosis with surgery [10].

Contrast-enhanced CT angiography was extremely useful in this case, as it showed both the aneurysm and distal thrombus which allowed the surgeons to take necessary steps after definitive diagnosis. Doppler ultrasound imaging was used as a first step imaging method without radiation exposure. The diagnosis was made quickly and accurately in the emergency room, but the patient’s delay in presenting for treatment 6 hours later delayed the early diagnosis and revascularization that are crucial in mesenteric ischemia, leading to the patient's death due to intestinal necrosis [11].

Visceral arterial aneurysms are very rare and associated complications might be fatal in the child population. Computed tomography angiography imaging provides a fast and accurate diagnosis and can delineate additional prognostic findings.