Median arcuate ligament syndrome (MALS) is secondary to compression of the coeliac artery by the median arcuate ligament¹ with secondary critical reduction in blood flow to the proximal duodenum and stomach. The diagnosis of MALS is problematic due to the frequent overlap with functional symptoms.² Doppler sonography may be used as an effective/primary imaging modality in the initial assessment of MALS which may remove the gold standard examination of CT angiography and limit the use of ionising radiation.³

A 14 year old girl presented with post-prandial abdominal pain, nausea and associated weight loss. She was under outpatient follow-up for a diagnosis of Postural Orthostatic Tachycardia syndrome and hypermobility (non-genetic Ehler’s Danlos). Investigations for her abdominal pain were normal (bloods, stool FCP, abdo ultrasound, barium meal). Upper GI endoscopy was also normal. She required a prolonged inpatient stay post endoscopy (pain and parasyncope) and was established on nasogastric feeds but reported ongoing pain and escalating vomiting and weight loss. CT angiography of the abdomen and pelvis was performed demonstrating an ostial stenosis (1mm orifice) at the origin of the coeliac axis, a characteristic hooked appearance at the location of the median arcuate ligament and post stenotic dilatation confirmed on axial slices and visually augmented using 3D reconstruction. Abdominal doppler USS, comparing SMA to CA flow, showed high velocity post stenotic flow in the coeliac axis (400 cm/s); double the value measured at the origin of the SMA (150 cm/s). She has now been established on jejunal feeds with excellent improvement in symptoms and no current plan for any surgical intervention. If symptoms persist she will have division of the MAL.

Merging the CT findings with the Doppler appearances suggest US may have a role in the early imaging assessment of a rare condition that is often a diagnostic conundrum.

References

1. Goodall R, Langridge B, Onida S, et al. Median arcuate ligament syndrome. J. Vasc. Surg. 2020 71;6:2170–2176.

2. Mak GZ, Speaker C, Anderson K et al. Median arcuate ligament syndrome in the pediatric population. J. Pediatr. Surg. 2013 Nov 1;48(11):2261–70.

3. Gruber H, Loizides A, Peer S, et al. Ultrasound of the median arcuate ligament syndrome: a new approach to diagnosis. Med. Ultrason. 2012 Mar 1;14(1):5–9.