Mesenteric Vascular Disease

Mesenteric Vascular Disease

Mesenteric Vascular Disease

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MVD: Intro & Anatomy - Gut Feeling Gone Wrong

  • Mesenteric Vascular Disease (MVD): Insufficient blood supply to intestines.
  • Key Types:
    • Acute Mesenteric Ischemia (AMI): Sudden arterial blockage.
    • Chronic Mesenteric Ischemia (CMI): Gradual narrowing; "intestinal angina".
    • Mesenteric Venous Thrombosis (MVT): Venous outflow obstruction.
  • Primary Arteries:
    • Celiac Trunk: Supplies foregut (e.g., stomach, duodenum).
    • Superior Mesenteric Artery (SMA): Supplies midgut (e.g., jejunum, ileum, right colon).
    • Inferior Mesenteric Artery (IMA): Supplies hindgut (e.g., left colon, rectum).
  • Critical Collaterals:
    • Marginal Artery of Drummond: Connects SMA & IMA branches.
    • Arc of Riolan (Meandering Mesenteric Artery): Direct SMA-IMA link. Mesenteric artery anatomy and collaterals

⭐ Superior Mesenteric Artery (SMA) is the most commonly affected vessel in acute mesenteric ischemia.

Acute Mesenteric Ischemia - Time Is Bowel

Life-threatening emergency; rapid diagnosis & intervention crucial. "Time is bowel." High mortality (~70-90% if delayed).

  • Types & Causes:
    • Arterial Embolic (~50%): Cardiac source (AF, MI).
    • Arterial Thrombotic (~25%): Atherosclerosis (often prior CMI).
    • Non-Occlusive (NOMI, ~20%): Low flow states (shock, vasopressors).
    • Mesenteric Venous Thrombosis (MVT, ~5%): Hypercoagulability, malignancy. 📌 Hypercoagulable, Inflammation, Malignancy, Portal HTN (HIMP).
  • Clinical:

    ⭐ Classic: Severe abdominal pain 'out of proportion' to physical findings.

    • N/V/D, bloody stools (late). Peritoneal signs = infarction.
  • Diagnosis:
    • Labs: ↑ Lactate (> 2 mmol/L), acidosis (pH < 7.35), ↑ D-dimer.
    • Imaging: CTA (gold standard). Algorithm for Suspected Acute Mesenteric Ischemia
  • Management Algorithm:

Chronic Mesenteric Ischemia - Slow Gut Starvation

  • Pathophysiology: Atherosclerosis (most common, >90%) leading to ↓ blood flow, typically requiring >70% stenosis in ≥2 major mesenteric arteries (celiac, SMA, IMA).
  • Clinical Presentation:
    • Often insidious onset.
    • ⭐ > Triad: Postprandial abdominal pain ("intestinal angina", ~30 min after meals, dull/crampy), significant weight loss (due to malabsorption & food fear), and food fear (sitophobia).
    • Abdominal bruit may be present (~50%).
  • Diagnosis:
    • Duplex ultrasound (screening).
    • CTA or MRA (confirmatory, preferred).
    • Conventional angiography (gold standard, allows intervention). CTA and MRA of mesenteric artery stenosis
  • Management: Revascularization (angioplasty/stenting or surgical bypass) is key. Nutritional support vital. 📌 Mnemonic: "Angina (intestinal), Weight loss, Food fear" (AWFul gut pain).
  • Ischemic Colitis (IC)
    • Most common mesenteric ischemia; typically non-occlusive (low flow).
    • Key sites: Watershed areas (splenic flexure, rectosigmoid junction).
    • Clinical: Sudden cramping LLQ pain, hematochezia, tenesmus.
    • Imaging: "Thumbprinting" (submucosal edema/hemorrhage) on CT/barium. CT scan: Thumbprinting in Ischemic Colitis

    ⭐ Ischemic colitis most commonly affects watershed areas like the splenic flexure and rectosigmoid junction.

  • Median Arcuate Ligament Syndrome (MALS)
    • Celiac artery compression by the median arcuate ligament of diaphragm.
    • Classic: Postprandial epigastric pain, weight loss, epigastric bruit (louder on expiration).
    • Diagnosis: Duplex US (↑ celiac velocity with expiration), CT/MR angiography (focal stenosis, hooked appearance). MALS Anatomy and Compression
  • Segmental Arterial Mediolysis (SAM)
    • Rare non-atherosclerotic, non-inflammatory vasculopathy; causes dissection/aneurysm.
    • Primarily affects splanchnic arteries (splenic, hepatic, SMA).
    • Pathology: Lysis of outer arterial media → weakness.
    • Presentation: Acute severe abdominal pain, intra-abdominal hemorrhage, shock; often younger patients.

High‑Yield Points - ⚡ Biggest Takeaways

  • Acute Mesenteric Ischemia (AMI): Severe pain "out of proportion" to findings; SMA embolism (AFib) is most common.
  • Chronic Mesenteric Ischemia (CMI): "Intestinal angina" (postprandial pain, weight loss, food fear) from atherosclerosis.
  • Diagnosis: CT Angiography (CTA) is gold standard. ↑ lactate is a late, poor prognostic sign in AMI.
  • AMI Treatment: Urgent revascularization (surgical/endovascular) ± bowel resection.
  • Mesenteric Venous Thrombosis (MVT): Linked to hypercoagulable states; primary treatment is anticoagulation.
  • Non-Occlusive Mesenteric Ischemia (NOMI): Due to low flow/vasoconstriction; treat cause, consider vasodilators.

Practice Questions: Mesenteric Vascular Disease

Test your understanding with these related questions

Tumour of the uncinate process of the pancreas will compress which artery

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Flashcards: Mesenteric Vascular Disease

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The most common artery involved in PVD is the _____ artery

TAP TO REVEAL ANSWER

The most common artery involved in PVD is the _____ artery

superficial femoral

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