Median arcuate ligament syndrome

Overview

Median Arcuate Ligament Syndrome (MALS), also known as celiac artery compression syndrome, is a rare condition in which the median arcuate ligament—a fibrous band of the diaphragm—compresses the celiac artery and/or the adjacent celiac plexus of nerves. This compression can lead to a variety of gastrointestinal symptoms, most notably postprandial abdominal pain (pain after eating), unintended weight loss, and nausea.

MALS is considered a diagnosis of exclusion, as its symptoms are nonspecific and overlap with many other more common gastrointestinal disorders. While many individuals may have anatomical compression of the celiac artery without symptoms, in MALS the compression also irritates the celiac nerve plexus, contributing to pain and digestive issues. The syndrome primarily affects young to middle-aged adults and is more commonly diagnosed in females.

Causes

MALS is caused by anatomical compression of the celiac artery and/or the celiac nerve plexus by the median arcuate ligament, a fibrous arch that connects the left and right diaphragmatic crura. This compression can lead to reduced blood flow to the upper abdominal organs and/or nerve irritation, both of which are believed to contribute to symptoms.

Key contributing factors include:

• Low origin of the celiac artery: In some individuals, the celiac artery originates higher than usual, making it more susceptible to being compressed by the median arcuate ligament.

• High insertion of the median arcuate ligament: A higher-than-normal position of the ligament increases the likelihood of vascular compression.

• Respiratory variation: The degree of compression may vary with breathing; it typically worsens during expiration when the diaphragm moves upward.

Although the condition is structural, only a small percentage of people with radiologic evidence of celiac artery compression actually develop symptoms.

Symptoms

The hallmark symptom of Median Arcuate Ligament Syndrome is chronic abdominal pain, particularly in the upper middle abdomen (epigastric area), that worsens after eating. Common symptoms include:

• Postprandial abdominal pain: Typically begins 15–30 minutes after meals and may last for several hours.

• Unintentional weight loss: Due to fear of eating or pain associated with meals.

• Nausea and vomiting

• Early satiety: Feeling full after eating only a small amount.

• Diarrhea or bloating: Less common but may be present.

• Epigastric bruit: A whooshing sound heard over the abdomen with a stethoscope, especially during expiration.

Symptoms are often chronic and can significantly affect a patient’s nutritional status and quality of life. However, due to their nonspecific nature, MALS is frequently misdiagnosed or missed altogether.

Diagnosis

Diagnosing MALS is challenging and requires a combination of clinical suspicion, imaging studies, and exclusion of other conditions. Diagnostic steps include:

• Clinical history and physical examination:

  • Focus on postprandial pain, weight loss, and presence of an abdominal bruit.

• Doppler ultrasound:

  • Measures blood flow velocities in the celiac artery; elevated peak systolic velocity, especially during expiration, suggests compression.

• CT angiography (CTA) or MR angiography (MRA):

  • Visualizes the celiac artery and confirms anatomical compression, often showing a “hooked” appearance of the artery.

• Conventional angiography with respiratory maneuvers:

  • May be performed for detailed visualization and confirmation of dynamic compression.

• Gastrointestinal work-up:

  • Endoscopy, labs, and imaging to rule out more common causes of abdominal pain and weight loss such as peptic ulcers, gallbladder disease, or inflammatory bowel disease.

A positive diagnosis often requires both radiological evidence of compression and corresponding symptoms that improve after surgical decompression.

Treatment

Treatment for MALS is typically surgical and aimed at relieving the compression of the celiac artery and celiac plexus. Management includes:

1. Surgical Decompression

• Median arcuate ligament release:

  • Involves dividing the ligament to relieve arterial and nerve compression.

  • Can be performed via open, laparoscopic, or robotic-assisted approaches.

• Celiac ganglionectomy:

  • Removal or ablation of the surrounding nerve plexus may be performed to reduce pain signals.

2. Vascular Reconstruction (in select cases)

• If arterial narrowing does not improve with decompression, procedures such as angioplasty or bypass grafting may be considered.

3. Supportive Management

• Dietary modifications: Small, frequent meals to minimize discomfort.

• Weight monitoring and nutritional support for patients with significant weight loss.

• Pain management: Short-term medications while awaiting surgery or during recovery.

Not all patients respond to surgery, so patient selection based on correlation of symptoms with imaging findings is critical.

Prognosis

The prognosis for patients with Median Arcuate Ligament Syndrome varies. In well-selected patients who undergo surgical decompression:

• 60–80% report significant symptom relief following surgery.

• Improved quality of life is often reported, with increased ability to eat and gain weight.

However, some patients may experience partial or no improvement, especially if symptoms are due to other functional gastrointestinal disorders. In these cases, ongoing medical management and evaluation for alternative diagnoses may be needed.

With timely diagnosis and appropriate intervention, many individuals can experience long-term symptom control and a return to normal activity and nutrition.