Early Detection of Superior Mesenteric Artery Dissection by Ultrasound: Two Case Reports

Abstract

Superior mesenteric artery (SMA) dissection is a rare disease. Some of the cases are isolated type, the others are associated with aortic dissection. Most of the cases are diagnosed by contrast-enhanced computed tomography (CECT). The use of emergent bedside ultrasound has been described to diagnose aortic dissection. However, there is limited literature regarding the use of bedside ultrasound to identify superior mesenteric artery dissection, a known high-risk feature of aortic dissection. We present one case of isolated SMA dissection and one case of SMA dissection complicated with aortic dissection. Both of them were diagnosed by bedside ultrasound first and confirmed by CECT Case report and literature review. Case one: A 46-year-old male patient without past history of hypertension. He suffered from intermittent epigastralgia for 3 days. Laboratory data, ECG, KUB showed no specific finding. Bedside ultrasound found faint intimal flap in SMA. The diameter of SMA was 15.4mm. Color duplex revealed thrombosis or false lumen in SMA. Cardiovascular specialist was informed and SMA dissection was proved by CECT. Patient’s symptom improved after anticoagulant usage. Case two: A 46-year-old male patient with past history of hypertension and old ischemic stroke. He had sudden onset of consciousness change and recurrent stroke was impressed initially. However, due to relative low systolic blood pressure (97mmHg), we performed bedside ultrasound to the patient and found intimal flap in abdominal aorta and SMA. The diameter of SMA was 10.5mm. Cardiovascular specialist was consulted immediately. Patient’s consciousness recovery to clear after endografting surgery. These two cases illustrate that bedside ultrasound can be used to early detect SMA dissection. The normal diameter of SMA was reported as 5.7-7.3mm. The aneurysm is considered more than 1.5 times of normal diameter. Intimal flap of SMA dissection may not be easily seen in ultrasound due to poor image quality. However, the diameter of SMA > 10 mm should warrant clinician the high suspicion of SMA dissection and further image study or specialist consultation should be considered.