Bile Excretion in Sphincter of Oddi Dysfunction
Yes, bile excretion is impaired in sphincter of Oddi dysfunction due to functional or structural obstruction at the sphincter level, which causes retention of bile in the biliary tree. 1
Pathophysiological Mechanism
Sphincter of Oddi dysfunction (SOD) represents a benign noncalculous obstruction of bile drainage at the sphincter level, which directly impairs bile flow from the biliary tree into the duodenum. 2 The condition can result from either:
- Sphincter of Oddi stenosis (structural narrowing) 1
- Sphincter of Oddi dyskinesia (functional motility abnormality) 1
Both mechanisms produce obstruction to flow through the sphincter, inducing retention of bile in the biliary tree. 1
Normal vs. Dysfunctional Bile Flow
Under normal circumstances, the sphincter maintains pressure in the common bile duct higher than the duodenum during fasting, then relaxes postprandially to allow coordinated bile excretion. 3 In SOD, this coordinated mechanism fails, resulting in:
- Impaired bile drainage from the hepatic hilum to the duodenum 1
- Increased biliary pressure from functional outflow obstruction 4
- Discoordination between gallbladder contraction and sphincter relaxation (when gallbladder is present) 4
Clinical Manifestations of Impaired Bile Excretion
The impaired bile excretion in SOD manifests as:
- Biliary-type pain (the hallmark symptom) 2, 1
- Transient elevations in liver enzymes (particularly in Type I and II SOD) 1, 5
- Common bile duct dilatation (in Type I SOD) 5
Diagnostic Confirmation
Quantitative evaluation of bile transit from the hepatic hilum to the duodenum using choledochoscintigraphy demonstrates slow bile transit, which confirms impaired bile excretion and is valuable in deciding whether to proceed with sphincter of Oddi manometry or treatment. 1
Post-Cholecystectomy Context
After cholecystectomy, denervation disrupts the coordinated neural control mechanism, leading to sphincter dysfunction in up to 5% of patients. 4, 3 The prevalence of biliary-type pain varies from 1-1.5% in unselected post-cholecystectomy patients to 14% in those with post-cholecystectomy symptoms. 1
Important Clinical Caveat
The degree of bile excretion impairment correlates with SOD classification: Type I patients (with pain, elevated liver enzymes, and dilated common bile duct) have the most severe obstruction with 65-95% showing manometric abnormalities, while Type III patients (pain only) have minimal objective evidence of obstruction with only 12-28% showing manometric abnormalities. 1, 5