Is Median Arcuate Ligament Syndrome (MALS) linked to EDS and POTS?

What is MALS?

‍Median Arcuate Ligament Syndrome (MALS) is a rare vascular compression disorder where the median arcuate ligament, a fibrous band of the diaphragm, compresses the celiac artery and surrounding nerves, leading to reduced blood flow and nerve irritation. This compression can cause a range of symptoms primarily affecting the gastrointestinal system, such as chronic abdominal pain, especially after eating, nausea, vomiting, and significant weight loss. MALS is often difficult to diagnose because its symptoms can be mistaken for other gastrointestinal disorders.

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Symptoms of Median Arcuate Ligament Syndrome (MALS)

‍The hallmark symptoms of MALS include:

• Chronic Abdominal Pain: Often described as epigastric pain that worsens after eating (postprandial pain) and can be severe enough to limit food intake.
• Nausea and Vomiting: These symptoms often accompany the abdominal pain and contribute to weight loss.
• Weight Loss: Due to the pain associated with eating, patients may avoid food, leading to significant weight loss.
• Epigastric Bruit: An abnormal sound heard with a stethoscope over the upper abdomen, caused by the turbulent blood flow through the compressed celiac artery.

Diagnosis of Median Arcuate Ligament Syndrome (MALS)

‍Diagnosing MALS can be challenging because its symptoms overlap with many other conditions. The diagnosis is often one of exclusion, meaning other causes of the symptoms must be ruled out first. Common diagnostic tools include:

• Doppler Ultrasound: Used to measure blood flow velocities in the celiac artery, especially during different phases of breathing.
• CT Angiography (CTA) or MR Angiography (MRA): These imaging techniques can visualize the celiac artery and reveal the characteristic "hooked" appearance of the artery as it is compressed by the median arcuate ligament.
• Celiac Plexus Block: A diagnostic procedure where an anesthetic is injected near the celiac plexus to temporarily relieve pain. A positive response to this block can help confirm MALS.

Treatment Options for MALS

‍The primary treatment for MALS is surgical, aiming to relieve the compression of the celiac artery and nerves. There are several surgical approaches:

• Laparoscopic or Open Surgery: The median arcuate ligament is divided to relieve the compression. This can be done through a minimally invasive laparoscopic approach or open surgery.
• Celiac Plexus Neurolysis: In some cases, the nerves of the celiac plexus are also treated to reduce pain.
• Revascularization Procedures: If the artery is severely damaged, additional procedures like stenting or bypass surgery may be necessary.

Is MALS Linked to EDS, POTS, and Dysautonomia?

‍MALS is increasingly recognized in patients with connective tissue disorders like Ehlers-Danlos Syndrome (EDS) and autonomic nervous system disorders like Postural Orthostatic Tachycardia Syndrome (POTS).

• Ehlers-Danlos Syndrome (EDS): EDS is a group of genetic connective tissue disorders that can cause hypermobility, fragile skin, and other vascular complications. In patients with EDS, the connective tissue abnormalities may predispose them to vascular compression syndromes like MALS. Studies have shown that EDS is more prevalent in patients with MALS than in the general population​​.
• Postural Orthostatic Tachycardia Syndrome (POTS): POTS is a form of dysautonomia characterized by an abnormal increase in heart rate upon standing. There is evidence that MALS is more common in patients with POTS. The overlap in symptoms between MALS and POTS, such as dizziness and gastrointestinal discomfort, suggests a possible link between these conditions​.

MALS in the Context of Vascular Compression Syndromes

‍MALS belongs to a broader category of vascular compression syndromes, which include conditions like May-Thurner Syndrome (MTS) and Nutcracker Syndrome. While these syndromes typically involve venous compression, MALS is unique in its involvement of arterial compression. Despite these differences, the impact on blood flow and the resulting symptoms share similarities across these conditions.

• May-Thurner Syndrome (MTS): This syndrome involves the compression of the left iliac vein by the right iliac artery, leading to venous insufficiency and an increased risk of deep vein thrombosis. MALS and MTS can coexist, especially in patients with underlying connective tissue disorders like EDS​.
• Nutcracker Syndrome: This syndrome is caused by the compression of the left renal vein between the superior mesenteric artery and the aorta. Like MALS, Nutcracker Syndrome can lead to abdominal pain, although it primarily affects the renal system.

Conclusion

Median Arcuate Ligament Syndrome (MALS) is a rare but significant condition that can cause chronic abdominal pain and other debilitating symptoms. Its links to conditions like EDS and POTS highlight the importance of considering MALS in patients with these disorders, particularly when they present with unexplained gastrointestinal symptoms. While surgical intervention is often necessary, careful diagnosis and patient selection are crucial to achieving the best outcomes. Understanding MALS and its connections to other vascular and autonomic conditions can help improve diagnosis, treatment, and overall patient care.

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References:

1. Moak, Jeffrey P., et al. "Median Arcuate Ligament Syndrome with Orthostatic Intolerance: Intermediate-Term Outcomes following Surgical Intervention." The Journal of Pediatrics, vol. 231, 2021, pp. 141-147. https://doi.org/10.1016/j.jpeds.2020.12.024.
2. Clark, Sarah. "ARFID or MALS - It's Not 'All in Your Head'." SEDSConnective, updated Nov 24, 2023. https://www.sedsconnective.org/post/arfid-or-mals-it-s-not-all-in-your-head.
3. Skelly, Christopher L., and Grace Z. Mak. "Median Arcuate Ligament Syndrome – Current State of Management." Seminars in Pediatric Surgery, 2021. https://doi.org/10.1016/j.sempedsurg.2021.151129.
4. Huynh, Desmond T. K., et al. "Median Arcuate Ligament Syndrome and Its Associated Conditions." American Surgeon, vol. 85, no. 10, 2019, pp. 1162-1165. https://doi.org/10.1177/000313481908501019.
5. Karhu, Elisa, and Linda Nguyen. "Safety and Efficacy of EUS-Guided Celiac Plexus Block in the Evaluation of Patients with Median Arcuate Ligament Syndrome Anatomy for Possible Surgery." IGIE, vol. 15, 2023. https://doi.org/10.1016/j.igie.2022.10.001.
6. Upshaw, Will, et al. "Overview of Median Arcuate Ligament Syndrome: A Narrative Review." Cureus, vol. 15, no. 10, 2023, e46675. https://doi.org/10.7759/cureus.46675.
7. Mohammed, Ahmad, et al. "Navigating Complexities: A Case of Multiple Abdominopelvic Vascular Compression Syndromes in Ehlers-Danlos Syndrome." Cureus, vol. 16, no. 7, 2024, e63848. https://doi.org/10.7759/cureus.63848.