The Role of Ultrasound in Dunbar Syndrome: Lessons Based on a Case Report

Abstract

Patient: Male, 55-year-old Final Diagnosis: Dunbar syndrome Symptoms: Epigastric pain • weight loss Medication: — Clinical Procedure: None Specialty: Gastroenterology and Hepatology • Radiology Objective: Rare disease Background: Dunbar syndrome is a rare vascular alteration caused by the abnormal course of the median arcuate ligament of the diaphragm, which in some patients causes chronic compression of the celiac artery and can cause non-specific symptoms such as diarrhea, retro-sternal pain, vomiting, swelling, and nausea, or a typical symptomatic triad with weight loss, post-prandial abdominal pain, and epigastric murmur. Color Doppler ultrasound and duplex Doppler ultrasound provide a complete diagnostic framework of this disease. Case Report: We describe a case of 55-year-old man with post-prandial epigastric pain, significant weight loss, and several episodes of retro-sternal pain. He underwent multidetector computed tomography of the abdomen and color duplex Doppler ultrasound examination of the celiac artery that highlighted stenosis of the celiac artery, more severe in expiratory apnea. The computed tomography showed the typical aspect of the celiac artery, with the “hook sign”. A duplex Doppler ultrasound examination showed a significant increase in peak speed (226 cm/s) due to severe stenosis of the celiac artery by the median arched ligament of the diaphragm. Conclusions: This case is unique due to the severity of the celiac artery stenosis and the unusual clinical presentation of the patient who had frequent episodes of retro-sternal pain. The significant increase in peak velocity in the celiac artery in expiratory apnea, if associated with the typical symptomatology in the absence of other alterations of the splanchnic vessels, can be considered, in our opinion, sufficient for the diagnosis of Dunbar syndrome.

Ultrasound characteristics of abdominal vascular compression syndromes

“…Another ultrasound criterion for diagnosing CACS includes measuring the PSV of the CA during the expiratory phase. A PSV of over 200 cm/s or a ratio of PSV of CA to aorta of greater than 3:1 in the expiratory phase can also indicate CACS (18)(19)(20)(21)(22)(23). In patients with an optimal sonographic window, the "hook" or "J" shape of the proximal CA caused by extrinsic compression by the MAL can be demonstrated in the sagittal plane with a B-mode or color Doppler imaging (24).…”

The ultrasound findings in a rare case of Nutcracker syndrome, Wilkie's syndrome, and Dunbar syndrome combination

“…Vascular compression syndromes represent a group of rare and poorly understood diseases. Dunbar syndrome (DS)[ 1 ] also known as Median Arcuate Ligament syndrome,[ 2 ] is caused by the median arcuate ligament of diaphragm originating lower than normal and causing celiac artery compression. When the median arcuate ligament insertion is less than normal, during the exhalation phases, with diaphragm elevation, the celiac artery compression occurs [ Figure 1a ]; these chronic compressions, if they become symptomatic, cause epigastric pain which intensifies with forced exhalation and after meals.…”

Vascular compression syndromes: a pictorial review

“…Median arcuate ligament syndrome (MALS), also known as DS [43] is caused by celiac artery (CA) compression and / or neural ganglion by median arcuate ligament (MAL) of diaphragm which, in these patients, has a lower insertion than normal and therefore, in exhalation phases, the lifting of diaphragm causes compression of CA (Fig. 8a).…”