Median arcuate ligament syndrome (MALS) occurs when the arc-shaped band of tissue in the chest area (median arcuate ligament) presses on, or traps, the artery that supplies blood to the organs in your upper abdomen (celiac artery).
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) and sits above the celiac artery without causing problems. 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).
MALS may occur in anyone, even children. Other names for MALS are:
- Celiac artery compression
- Celiac axis syndrome
- Dunbar syndrome
Treatment involves surgery to release (decompress) the ligament and restore blood flow through the artery.
Often, compression of the celiac artery doesn't cause any symptoms.
However, those with MALS can have long-term (chronic) stomach pain. Signs and symptoms of MALS include:
- Pain in the upper middle stomach area, which may go away when leaning forward
- Stomach pain after eating, exercising or shifting body position
- Fear of eating food due to pain, leading to significant weight loss — usually greater than 20 pounds (9.1 kilograms)
- Nausea and vomiting
Your doctor may hear an abnormal 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.
When to see a doctor
There are many different causes of stomach pain. If you have stomach pain that continues despite home care, call your doctor. You'll need a complete physical exam and tests to determine the specific cause.
If your stomach pain is severe and activity or movement makes it worse, call your doctor immediately. Seek immediate medical help if your stomach pain occurs with other concerning signs and symptoms, including:
- Bloody stools
- Nausea and vomiting that doesn't go away
- Severe tenderness when you touch your belly area
- Swelling of the belly area
- Yellowing of the skin or whites of the eyes (jaundice)
Sometimes upper stomach pain can be confused with chest pain. Get emergency help or call 911 if you have chest or upper stomach pain with or without any of the following symptoms, which might signal a heart attack.
- Pressure, fullness or tightness in your chest
- Crushing or searing pain that spreads to your jaw, neck, shoulders, and one or both arms
- Pain that lasts more than a few minutes or gets worse with activity
- Cold sweats
- Dizziness or weakness
- Nausea or vomiting
- Shortness of breath
Doctors aren't exactly sure what causes median arcuate ligament syndrome. The causes and diagnosis of MALS has been a subject of controversy. The signs and symptoms may be due to a lack of blood flow through the celiac artery, or compression on the nerves (neurological) of the celiac ganglion causing the pain.
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, which can lead to a fear of eating and significant weight loss. The pain and related depression or anxiety can greatly impact your quality of life. Because MALS symptoms may be vague and mimic other conditions, it may take some time to get an accurate diagnosis.