CASE 16973 Published on 18.08.2020

Difficult but not impossible! Ultrasonographic detection of isolated superior mesenteric artery dissection

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Bhavik Shah1, Gautami Sonara1, Gaurav Goswami1, Bhavin Patel1, Tejas Modi2

Department of Radiology, Zydus hospitals, Ahmedabad, Gujarat, India

Department of Gastroenterology and Hepatology, Zydus hospitals, Ahmedabad, Gujarat, India

Patient

55 years, male

Categories
Area of Interest Abdomen ; Imaging Technique CT-Angiography, Ultrasound, Ultrasound-Colour Doppler
Clinical History

A 55-year-old male presented to the gastroenterology/hepatology department with vague abdominal pain and bloating since about 3days. Patient was hypertensive. His abdomen was soft, non-tender and non-distended. He was referred to radiology department for ultrasound of abdomen.

Imaging Findings

Ultrasound of the abdomen revealed an eccentric thrombus in proximal superior mesenteric artery (SMA) extending for a length of about 2cm.The SMA origin was normal. Distal to the thrombus, an intimal flap was seen extending up to the terminal SMA. No thrombosis was seen in either the false lumen or the true lumen.

Increased echogenicity of fat was seen around the SMA.

No signs of bowel ischemia were seen.

Computed tomography (CT) of the abdomen with angiography confirmed the diagnosis. The aorta, celiac and inferior mesenteric arteries were normal, no dissection or thrombosis was seen.

Discussion

Isolated Superior Mesenteric Artery Dissection (ISMAD) is usually seen in middle-aged males. Common symptoms are acute or chronic epigastric or upper left quadrant pain which can be related to meals. Other symptoms are nausea, vomiting, and diarrhoea [1-4].

Spontaneous isolated SMA dissection has been reported in association with atherosclerosis, cystic medial necrosis, hypertension, fibromuscular dysplasia, vasculitis and trauma. The exact pathogenesis of an ISMAD remains uncertain. The dissection typically spares the origin of the super mesenteric artery, beginning 1.5 to 3 cm from the orifice of the SMA [5,6]. The prevalence of hypertension (HTN) among patients with an ISMAD is high, however, no direct cause-effect relationship with HTN was established [7]-

The abnormal “shear stress” can result in injury to the artery at the transition at the lower margin of the pancreas, from a fixed to a relatively mobile state of the SMA [8-10].

CT Angiogram (CTA) is considered the gold standard for diagnosis as it allows the demonstration of the dissection flap, thrombosis, true and false lumens [11].

We detected ISMAD on ultrasound of abdomen. Increased SMA diameter with an increase in surrounding fat attenuation can be useful in diagnosis [12,13,14]. Three-dimensional CT scans can allow a better delineation of the anatomy and the distance between the SMA ostium and origin of the dissection.

Complications of an ISMAD are bowel infarction, acute peritonitis, rupture into peritoneal cavity can result in intra-abdominal hemorrhage, hemorrhagic shock and death.

Generally, asymptomatic ISMAD patients or patients with a patent dual-lumen artery without aneurysm formation respond best to medical therapy [15]. Surgical intervention with endovascular stent placement is indicated among patients who are at risk for bowel ischemia or those who develop aneurysmal enlargement or rupture [15].

Our patient was treated medically and was kept on antihypertensive and anticoagulant drugs. Patient came for follow up after around fifteen to twenty days and had no symptoms during that period.

Teaching points

Skilled sonographic techniques with good knowledge of the entity and based on the clinical presentations, it is possible to detect ISMAD on sonography which can be confirmed further by CTA.

ISMAD should be suspected when other common causes of acute abdominal pain have been excluded.

Based on the clinical condition and extent of the dissection, management options include conservative treatment and anticoagulation, endovascular stenting, or open surgical repair.

Differential Diagnosis List
Isolated SMA dissection
SMA aneurysm
SMA thrombosis
SMA syndrome
aortic dissection extending to SMA
Final Diagnosis
Isolated SMA dissection
Case information
URL: https://www.eurorad.org/case/16973
ISSN: 1563-4086
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