Biliary Tract: Sphincter of Oddi Dysfunction (SOD)

Causes

• Stenosis – Narrowing from Gallstone, Pancreatitis, Trauma, Malignancy or Infection
• Dyskinesia – Functional Disturbance
• Most Commonly Found After Cholecystectomy Due to Unmasking of Pre-Existing SOD

Types

• I: Pain, Abnormal LFT & Dilated CBD
• II: Pain, Abnormal LFT or Dilated CBD
• III: Pain, Normal LFT & CBD

Diagnosis

• Tests:
  • Gold Standard: Sphincter of Oddi Manometry (SOM)
  • Nardi Test (Morphine & Neostigmine Cause Pain)
  • HIDA (Hepatobiliary Scintigraphy)
• Work-Up:
  • Type I – Likely Underlying Obstruction
    • Proceed with ERCP
  • Type II – SOD Suspected
    • Proceed with SOM Before Tx
  • Type III – SOD vs Functional Bowel Disease
    • Avoid Invasive Testing; Proceed with Medical Tx

Treatment

• Type I/II: ERCP & Endoscopic Sphincterotomy
  • If Fails or in a Gastric Bypass Patient: Surgery (Transduodenal Sphincteroplasty)
• Type III: Medical Tx (CCB/Ursodeoxycholic Acid)