Symptoms of Median Arcuate Ligament Syndrome (MALS)
The classic symptom triad of MALS consists of postprandial epigastric pain, weight loss, and sitophobia (fear of eating). 1
Primary Clinical Manifestations
Abdominal Pain Characteristics
- Postprandial epigastric pain is the hallmark symptom, typically worsening after meals 2, 1, 3
- Pain may be exercise-induced in addition to meal-related 3
- The pain is often described as severe and excruciating 4, 5
- Pain episodes can be chronic and recurrent, persisting for months before diagnosis 4
Gastrointestinal Symptoms
- Nausea is commonly reported 1, 3, 4
- Vomiting (including bilious vomiting) occurs frequently, particularly worsening after meals 1, 3, 5
- Anorexia or loss of appetite may develop 4, 6
- Diarrhea can be present in some patients 4
Constitutional Symptoms
- Significant weight loss is a defining feature, often 20 pounds or more 2, 1
- Weight loss occurs despite maintained appetite, distinguishing MALS from malignancy 2
- Sitophobia (food fear) develops as patients avoid eating to prevent pain 2
Physical Examination Findings
- An epigastric bruit may be audible on auscultation 2, 5
- Physical examination is otherwise often unremarkable in many cases 4
- Abdominal examination may reveal epigastric tenderness 5
Important Clinical Context
Predictors of Symptomatic MALS
The American College of Radiology identifies specific predictors associated with successful surgical outcomes that help characterize true symptomatic MALS 2, 1:
- Postprandial pain pattern (81% cure rate with surgery)
- Age between 40-60 years (77% cure rate with surgery)
- Weight loss of 20 pounds or more (67% cure rate with surgery)
Critical Diagnostic Caveat
Celiac artery compression by the median arcuate ligament is present in 20% of the general population and may be completely asymptomatic 2, 1. This means imaging findings alone do not confirm symptomatic MALS—the diagnosis requires correlation between radiographic compression and the characteristic symptom complex after excluding other causes 2, 7.
Demographics
- MALS predominantly affects females 6
- Median age of presentation is typically in the third to fourth decade 6
Pathophysiologic Mechanisms
The symptoms arise from two proposed mechanisms 4, 6:
- Vascular compression causing foregut ischemia 3, 4
- Neurogenic compression of the celiac ganglion and splanchnic plexus causing altered pain sensation 4, 6
Histopathologic findings support the neurogenic theory, showing periganglionic and perineural fibrosis with proliferation of small nerve fibers in surgical specimens 6.