median arcuate ligament syndrome

Dr Peter Carr-Boyd is a specialist general surgeon with broad sub-specialty training in uppergastrointestinal surgery, including extensive experience in assessing and managing complex upper abdominal conditions. This breadth of expertise ensures appropriate investigations are performed to exclude more common causes of symptoms and that any procedures, including MALS surgery, are undertaken appropriately, safely, and at the right time, using minimally invasive techniques wherever possible to reduce risk and speed recovery.

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What is Median Arcuate Ligament Syndrome?

Median Arcuate Ligament Syndrome (MALS) is a rare condition that causes chronic upper abdominal pain due to compression of important blood vessels and nerves supplying the stomach, liver, pancreas, and intestines. The problem arises when the median arcuate ligament, a fibrous band of the diaphragm, presses on the celiac artery and nearby celiac nerve plexus.

This compression is often worse during breathing out (expiration), when the diaphragm moves upward. Over time, this pressure can interfere with blood flow and irritate surrounding nerves, leading to ongoing symptoms.

How Does MALS Cause Symptoms?

MALS symptoms are thought to occur due to two overlapping mechanisms:

Reduced blood flow to the digestive organs, especially after eating when blood demand increases
Nerve irritation from compression of the celiac plexus, causing chronic or neuropathic pain

Together, these factors explain why symptoms can be persistent, fluctuate in severity, and be difficult to diagnose. Many patients experience symptoms for months or years before MALS is identified.

Common Symptoms of MALS

Symptoms of Median Arcuate Ligament Syndrome can vary, but commonly include:

Upper abdominal or epigastric pain, often worse after meals
Nausea or vomiting
Early fullness when eating
Unintentional weight loss
Bloating or abdominal discomfort
Pain that may improve when leaning forward or worsen with exercise

Because these symptoms overlap with many other gastrointestinal conditions, MALS is often a diagnosis of exclusion.

How is MALS Diagnosed?

Diagnosing MALS requires careful assessment by a specialist upper gastrointestinal. There is no single test that confirms MALS, and imaging findings alone do not always explain symptoms.

Investigations commonly include:

CT angiography (CTA) with breathing protocols
Duplex or Doppler ultrasound assessing coeliac artery flow during inspiration and expiration
Additional tests to exclude other gastrointestinal, vascular, or functional disorders

A characteristic narrowing of the coeliac artery (often described as a “hooked” appearance) may be seen on imaging, but symptoms and imaging must be interpreted together.

When Should You consider Seeing a Specialist?

We recommend you book an assessment if you experience:

Ongoing or persistent upper abdominal pain, especially after eating
Unexplained weight loss, nausea, or early fullness
Symptoms that do not improve with standard medical treatments like proton pump inhibitors
Previous investigations that have not identified a clear cause

Accurate diagnosis is essential, as symptoms often overlap with more common gastrointestinal conditions. Dr Peter Carr-Boyd provides comprehensive assessment for suspected Median Arcuate Ligament Syndrome (MALS), ensuring the diagnosis is only made after other potential causes of symptoms have been carefully excluded. This evaluation typically includes targeted blood tests, advanced imaging, and endoscopic assessment with gastroscopy and colonoscopy where appropriate. This approach helps find the cause of symptoms and ensures that any treatment offered is appropriate, evidence-based, and timely.