Biliary Dyskinesia and Sphincter of Oddi Dysfunction (SOD)

Biliary Dyskinesia

Definition

Biliary dyskinesia is a disease characterized by right upper quadrant biliary-type pain in the absence of gallstones.
Also known as:
- Chronic acalculous cholecystitis
- Acalculous biliary pain
- Functional gallbladder disorder
Presumed to result from abnormal motile function of the gallbladder.
Frequency:
- Up to 8% in men
- Up to 21% in women

Physiology

Gallbladder Function:
- Stores and concentrates bile produced by the liver.
- Empties through contraction of its smooth muscle wall.
- Coordinated with sphincter of Oddi relaxation.
Gallbladder Emptying:
- Fasting State: Partially empties cyclically with the migrating motor complex.
- Post-Meal: Stimulated by:
  - Neural reflex stimuli
  - Enterohormonal cues (e.g., cholecystokinin (CCK))

Pathophysiology

Incomplete Understanding but possible factors include:
- Cystic Duct Narrowing:
  - Due to inflammation or fibrosis.
  - Causes obstruction to gallbladder emptying.
- Intrinsic Motility Disorder:
  - Affects smooth muscle of the gallbladder wall or cystic duct.
- Associations with Other Disorders:
  - Irritable bowel syndrome
  - Colonic inertia
  - Gastroparesis
- Alterations in Bile Composition
- Inflammatory Mediators (e.g., prostaglandin E2)
Histology:
- Up to 43% show no histologic abnormalities after cholecystectomy.
Conclusion:
- Encompasses a diverse group with variable factors leading to poor gallbladder emptying.

Clinical Presentation

Pancreatobiliary-Type Pain (per Rome IV criteria):
- Located in the right upper quadrant or epigastrium.
- Colicky nature.
- Occurs postprandially.
- Associated with:
  - Nausea
  - Bloating
  - Emesis
  - Diarrhea
- May report anorexia and weight loss.

Diagnosis

Essential Component: Typical pain history.
Physical Examination:
- May show abdominal tenderness in the right upper quadrant.
- Often entirely benign.
Laboratory Tests:
- Liver biochemistries and pancreatic enzymes are usually normal.
Imaging:
- Transabdominal ultrasound to exclude gallstones (sensitivity >95%).
Differential Diagnosis:
- Peptic ulcer disease
- Sphincter of Oddi dysfunction (SOD)
- Microlithiasis
- Chronic pancreatitis
- Functional gut motility disorders
CCK-Stimulated HIDA Scan (CCK-HIDA):
- Cornerstone diagnostic test.
- Measures gallbladder ejection fraction (EF).
- Abnormal EF: Less than 35-40%.
- Controversies:
  - Testing methodology.
  - Correlation with treatment outcomes.
  - Pain reproduction during CCK infusion lacks supporting evidence.

Treatment

Cholecystectomy:
- Primary treatment for biliary dyskinesia.
- Laparoscopic cholecystectomy has increased its frequency.
- Accounts for:
  - 10-20% of adult cases in the U.S.
  - Up to 50% in children.
Outcomes:
- Variable results reported.
- Studies:
  - Yap et al. (1991):
    - Significant symptom resolution in patients with abnormal CCK-HIDA after surgery.
  - Richmond et al. (2016):
    - Improved quality of life after cholecystectomy.
- Conclusion:
  - Larger studies needed to better define outcomes.

Sphincter of Oddi Dysfunction (SOD)

Definition

A functional disorder causing non-calculous obstruction of biliary or pancreatic secretions.
Also known as:
- Ampullary stenosis
- Papillary stenosis
- Papillitis
- Postcholecystectomy syndrome
Involves abnormal contractile function of the ampullary sphincter.
Affects mostly middle-aged women.
Contributes to:
- Postcholecystectomy pain
- Idiopathic recurrent pancreatitis

Anatomy and Physiology

Location:
- At the terminal portions of the common bile duct and main pancreatic duct.
- Entering the second portion of the duodenum.
Sphincter Structure:
- Common muscular complex (ampullary zone).
- Intrapancreatic and intrabiliary sphincteric mechanisms.
Function:
- Baseline elevated pressure zone with phasic contractions.
- Cyclical motor activity associated with the migrating motor complex.
Influences:
- Neural: Parasympathetic and sympathetic systems.
- Hormonal:
  - Cholecystokinin (CCK): Potent inhibitor.
  - Secretin: Inhibits the pancreatic portion.

Pathophysiology

Aberrations in sphincter function leading to elevated intraductal pressures.
Types of Obstruction:
- Fixed obstruction: Due to a stenotic ampulla.
- Functional obstruction: Due to abnormal motility.
Alternative Theories:
- Interruption of cholecystosphincteric reflex post-cholecystectomy.
- Nociceptive sensitization from inflammation.

Clinical Presentation

Typical pancreatobiliary-type pain (per Rome IV criteria):
- Episodic upper abdominal pain.
- Postprandial onset.
- Associated with nausea.
Physical Examination:
- Generally unremarkable.
Laboratory Findings:
- May have transient elevation of liver or pancreatic enzymes.
Complications:
- Recurrent idiopathic pancreatitis.

Diagnosis

Clinical History:
- Consistent pancreatobiliary-type pain.
Exclusion of Other Causes:
- Use of CT scans, endoscopy, and other tests.
Laboratory Tests:
- Check for transient enzyme elevations.
Milwaukee Classification (historical):
- Type I: Pain with all objective findings (enzyme elevations, ductal dilation).
- Type II: Pain with one objective finding.
- Type III: Pain only.
Endoscopic Retrograde Cholangiopancreatography (ERCP) with Endoscopic Sphincter of Oddi Manometry (ESOM):
- Standard diagnostic test.
- Measures ductal pressures.
- Elevated pressures (>35-40 mm Hg) indicate SOD.
- Risks:
  - Pancreatitis (4% to 31% incidence).
Other Diagnostic Tests:
- Nardi Test (morphine-prostigmine provocation).
- Biliary Scintigraphy.
- Ultrasound Stimulation Tests.
- Secretin-Stimulated MRCP (ssMRCP).

Treatment

Medical Management

Limited success.
Medications:
- Smooth muscle relaxants (e.g., nifedipine).
- Phosphodiesterase inhibitors.
- Trimebutine.
- Hyoscine butylbromide.
- Nitric oxide donors.
Alternative Therapies:
- Amitriptyline.
- Duloxetine.
- Electroacupuncture.
- Biofeedback.

Endoscopic Treatment

Endoscopic Sphincterotomy (ES):
- Primary treatment for types I and II SOD.
- Success Rate: 55% to 95% pain relief.
- Risks:
  - Post-ERCP pancreatitis (10% to 15% incidence).
  - Restenosis (25% to 33%).
EPISOD Trial Findings:
- Type III SOD (pain only) patients do not benefit from ES.
- ES is not recommended for patients without objective findings.

Surgical Treatment

Indications:
- Failed endoscopic intervention.
- Previous gastric surgery patients (e.g., gastric bypass).
Transduodenal Sphincteroplasty with Pancreatic Septoplasty:
- Operative procedure to divide the sphincter and septum.
- Technique:
  - Midline laparotomy with a Kocher maneuver.
  - Duodenotomy and identification of the ampulla.
  - Sphincterotomy and septotomy performed.
  - Mucosal approximation with fine sutures.
- Outcomes:
  - Over 60% experience long-term pain relief.
  - Poorer outcomes in:
    - Younger patients
    - Patients with chronic pancreatitis

Post-Gastric Surgery Patients

Challenges:
- Altered anatomy makes diagnosis and treatment difficult.
Diagnosis:
- History and laboratory evidence are crucial.
- ssMRCP to evaluate ductal dilation and exclude other pathologies.
Treatment Options:
- Surgical sphincteroplasty is effective.
- Endoscopic access via the excluded stomach (alternative approach).

Key Points

Biliary dyskinesia and SOD are functional disorders causing pancreatobiliary pain syndromes.
Diagnosis relies on:
- Typical pain history
- Exclusion of other causes
- Specific diagnostic tests (e.g., CCK-HIDA, ESOM)
Treatment options:
- Biliary dyskinesia:
  - Cholecystectomy is primary.
  - Outcomes vary; more research is needed.
- SOD:
  - Endoscopic sphincterotomy for types I and II.
  - Surgical sphincteroplasty for failed endoscopic cases or altered anatomy.
Clinical Practice:
- Proper patient selection is crucial for successful outcomes.
- Awareness of risks associated with diagnostic and therapeutic procedures.

Note: This revision consolidates key information from the provided context into a structured format with highlighted keywords for efficient study and review.