Segmental arterial mediolysis

Segmental arterial mediolysis (SAM) is a rare disorder of the arteries characterized by the development of aneurysms, blood clots, narrowing of the arteries (stenoses), and blood collections (hematomas) in the affected distribution.[1][2]

SAM most commonly affects the arteries supplying the intestines and abdominal organs.

Signs and Symptoms

Varies depending on the location of the affected blood vessels.

Gastrointestinal System:[3]

  • Acute abdominal pain (most common)[4]
  • Flank pain
  • Nausea
  • Vomiting
  • Diarrhea
  • Bloody stools
  • Back pain

Nervous System[3]

  • Headache
  • Stroke

The most severe signs occur if an aneurysm ruptures potentially resulting in:[4]

  • Shock
  • Loss of consciousness
  • Bleeding into the abdominal cavity
  • Bleeding into the brain

Mechanism

  1. The middle layer of an artery, called the media, made of smooth muscle is damaged.[3]
  2. Mediolysis occurs when the smooth muscle cells in the area of damage are destroyed.[3]
  3. Small gaps are formed in the wall of the artery which then fill with blood.[3]
  4. Gaps create weakness in the wall of the artery, allowing increasing pressure from blood to expand the gaps resulting in an aneurysm.[3]
  5. Aneurysms have potential for rupture.[3]

Diagnosis

Often Segmental Arterial Mediolysis is diagnosed after clinical presentation with symptoms as above followed by CT angiogram or MRI demonstrating aneurysm(s).[4] The gold standard method for confirming the diagnosis is surgical resection of the affected area of blood vessel followed by histologic investigation under a microscope.[3] Segmental Arterial Mediolysis must be differentiated from fibromuscular dysplasia, atherosclerosis, and other systemic vasculidites including polyarteritis nodosa, Takayasu's arteritis, Behcet's disease, cystic medial necrosis, and cystic adventitial artery disease.[4]

Treatment

Patients presenting with bleeding into the abdominal cavity require possible blood transfusions and emergent intervention with coil embolization via catheter angiography.[3] Patients without active bleeding, but diagnosed aneurysms should have strict blood pressure control with antihypertensive drugs to decrease the risk of aneurysm rupture.[3]

Epidemiology

Since it was first reported in 1976[5] there have been 101 documented cases of Segmental Arterial Mediolysis.[6] Although typically seen in older patients with an average age of 57 years old,[6] it can affect patients of any age and does not favor one gender or the other.[5]

References

  1. ↑ Ko, M; Kamimura, K; Sakamaki, A; Niwa, Y; Tominaga, K; Mizuno, K; Terai, S (22 July 2019). "Rare Mesenteric Arterial Diseases: A Case Report of Fibromuscular Dysplasia and Segmental Arterial Mediolysis and Literature Review". Internal Medicine (Tokyo, Japan). 58 (23): 3393–3400. doi:10.2169/internalmedicine.3094-19. PMC 6928505. PMID 31327836.
  2. ↑ Ko, M; Kamimura, K; Ogawa, K; Tominaga, K; Sakamaki, A; Kamimura, H; Abe, S; Mizuno, K; Terai, S (28 August 2018). "Diagnosis and management of fibromuscular dysplasia and segmental arterial mediolysis in gastroenterology field: A mini-review". World Journal of Gastroenterology. 24 (32): 3637–3649. doi:10.3748/wjg.v24.i32.3637. PMC 6113722. PMID 30166859.
  3. 1 2 3 4 5 6 7 8 9 10 Pillai, Anil Kumar; Iqbal, Shams I.; Liu, Raymond W.; Rachamreddy, Niranjan; Kalva, Sanjeeva P. (2014-02-20). "Segmental Arterial Mediolysis". CardioVascular and Interventional Radiology. 37 (3): 604–612. doi:10.1007/s00270-014-0859-4. ISSN 0174-1551. PMID 24554198.
  4. 1 2 3 4 Tan, Rebekah (2019-09-30). "Segmental Arterial Mediolysis: A Case Study and Review of the Literature in Accurate Diagnosis and Management". Vascular Specialist International. 35 (3): 174–179. doi:10.5758/vsi.2019.35.3.174. ISSN 2288-7970. PMID 31620405.
  5. 1 2 Ko, Masayoshi; Kamimura, Kenya; Sakamaki, Akira; Niwa, Yusuke; Tominaga, Kentaro; Mizuno, Kenichi; Terai, Shuji (2019-12-01). "Rare Mesenteric Arterial Diseases: Fibromuscular Dysplasia and Segmental Arterial Mediolysis and Literature Review". Internal Medicine. 58 (23): 3393–3400. doi:10.2169/internalmedicine.3094-19. ISSN 0918-2918. PMID 31327836.
  6. 1 2 Kim, Hyun Soo; Min, Sang-il; Han, Ahram; Choi, Chanjoong; Min, Seung-Kee; Ha, Jongwon (2016-08-11). "Longitudinal Evaluation of Segmental Arterial Mediolysis in Splanchnic Arteries: Case Series and Systematic Review". PLOS ONE. 11 (8): e0161182. Bibcode:2016PLoSO..1161182K. doi:10.1371/journal.pone.0161182. ISSN 1932-6203. PMID 27513466.
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