MALS (Median arcuate ligament syndrome) occurs when the arc-shaped band of tissue in the chest area (median arcuate ligament syndrome) presses on the celiac artery that sends blood to the upper abdomen which causes stomach pain in some people. The location of the median arcuate ligament and celiac artery varies slightly from person to person. Typically, the ligament runs across the largest blood vessel in the body (aorta). It sits above the celiac artery. But sometimes the ligament or artery may be out of place, causing MALS. The ligament may also put pressure on the network of nerves surrounding the celiac artery (celiac plexus).
The median arcuate ligament is located at the T12-L1 level and bridges the crura of the diaphragm, just anterior to the aorta. The celiac plexus is located between the arcuate ligament and the celiac trunk in up to 25% of normal individuals. Compression of the celiac trunk is, among other causes, secondary to diaphragm descensus after a period of accelerated growth in adolescents.
The condition has a 3:1 female-to-male ratio and the classic patient is a woman aged between 18 and 30 years. MALS is a rare entity, diagnosed in only 2 of 100,000 patients with ambiguous upper abdominal pain. This disease’s incidence is unknown; typical symptoms are chronic or recurring epigastric pain (especially post-prandial), nausea, vomiting, diarrhoea, weight loss, epigastric bloating, and reduced appetite. Since these symptoms may be caused by other diseases, like esophagitis, pancreatitis, cholelithiasis, and food intolerance, MALS is a diagnosis of exclusion.
The classic manifestation of abdominal angina is seen in about 40% of patients. Two theories have been suggested to explain symptoms: compression of the mesenteric artery with mesenteric ischemia and splanchnic vasoconstriction due to stimulation of the celiac ganglion and celiac plexus. Pain seems to be related to mechanical irritation of the celiac plexus nerve fibres.
As in the present case, an epigastric bruit may be detected on clinical examination.
Other names for MALS are:
- Celiac artery compression syndrome CACS
- Celiac axis syndrome
- Dunbar syndrome
Treatment involves surgery to release (decompress) the ligament and restore blood flow through the artery.
Because the cause of MALS is poorly understood, the risk factors for the syndrome are unclear. MALS has been seen in children, even twins, which might mean genetics plays a role. Some people have developed MALS after pancreatic surgery and blunt injury to the upper stomach area.
MALS Complications include long-term pain, especially after meals. The pain can lead to a fear of eating and significant weight loss. The pain and related depression or anxiety can greatly impact the quality of life. MALS symptoms may be vague and can mimic other conditions. It may take some time to get an accurate diagnosis.
There’s no specific test to diagnose MALS. Your healthcare provider will carefully examine you and ask questions about your symptoms and health history. Bloodwork and imaging tests help your provider rule out other causes of stomach pain. Diagnosis of Dunbar syndrome may be made by selective angiography, magnetic resonance angiography; spiral computed tomographic angiography, and Doppler ultrasound. The combination of colour duplex sonography and gastric exercise tonometry has been reported as having excellent accuracy for the diagnosis. Your health care provider may hear a sound called a bruit when listening to your upper stomach area with a stethoscope. The sound occurs when a blood vessel is blocked or narrowed.
Surgery is the only treatment option for MALS. The most common procedure is called median arcuate ligament release, or median arcuate ligament decompression. It’s usually done as an open surgery. Sometimes it can be done as a minimally invasive (laparoscopic or robotic) procedure. While you’re under general anaesthesia, a surgeon splits the median arcuate ligament and network of nerves in the stomach area (celiac plexus). Doing so provides more room for the artery. It restores blood flow and relieves pressure on the nerves. Some people with MALS may need open surgery to repair or replace a blocked celiac artery and fully restore blood flow (revascularization).