Lecture on Sphincter of Oddi Dysfunction (SOD)

May 29, 2024

Mindmap

Lecture on Sphincter of Oddi Dysfunction (SOD)

Overview

  • Sphincter of Oddi Dysfunction (SOD): A group of rare conditions resulting from spasms, narrowing, or inappropriate relaxation of the sphincter of Oddi.
  • Sphincter of Oddi: Muscular valve between the biliary tree and small intestine that regulates bile and pancreatic juice flow and prevents reflux of intestinal content.
  • Usual Consequence of SOD: Disrupted bile and pancreatic juice flow leading to biliary pain, typically in the upper right abdominal quadrant.

Types of SOD

  1. Type I: Biliary pain, elevated liver enzymes, dilated common bile duct.
  2. Type II: Biliary pain, elevated liver enzymes or dilated common bile duct.
  3. Type III: Biliary pain only.

Causes and Risk Factors

  • Cause: Unclear.
  • Risk Factors: Being assigned female at birth, age 20–50 years, history of gallbladder removal.

Symptoms

  • Main Symptom: Intermittent attacks of biliary pain.
    • Type of pain: Crampy abdominal pain, located in the upper right quadrant, may radiate to the back and shoulder.
    • Duration: Longer than 30 minutes, can resolve spontaneously.
  • Other Symptoms: Nausea, vomiting, pancreatitis.

Diagnosis

  • History & Physical Examination: Initial step to rule out common causes of biliary pain.
  • Blood Tests: Check for elevated liver and pancreatic enzymes (types I or II).
  • Imaging: Ultrasound, CT, MRI, HIDA scan to assess liver, gallbladder, and biliary function.
  • Gold Standard: Endoscopic Retrograde Cholangiopancreatography (ERCP) with manometry.

Treatment

  • Non-invasive Treatments:
    • Medications: Calcium channel blockers, tricyclic antidepressants.
  • Invasive Treatments:
    • Sphincterotomy: Surgically cutting the sphincter.
    • Botulinum Toxin Injections: Prevent spasms or narrowing.
  • For Non-responders:
    • Lifestyle modifications (e.g., low-fat diet).
    • Pain control: Consult with pain specialists; non-pharmacologic and pharmacologic methods.
    • Psychosocial support: Cognitive behavior therapy, other alternative therapies.

Recap

  • Cause: Unknown conditions causing inappropriate sphincter of Oddi function.
  • Symptoms: Intermittent biliary pain, nausea, vomiting, pancreatitis.
  • Diagnosis: ERCP with manometry plus supplemental tests.
  • Treatment: Combination of non-invasive and invasive interventions; lifestyle changes, pain control, and psychosocial support.

Focus, learn, retain, and thrive in your medical practice!