CBD Stones and Jaundice: Understanding Common Bile Duct Obstruction

CBD Stones and Jaundice: Understanding Bile Duct Obstruction

When gallstones migrate from the gallbladder into the common bile duct (CBD), they can cause one of the most recognisable signs of liver and bile duct disease: jaundice — the yellow discolouration of the skin and whites of the eyes. This comprehensive guide explains what happens when bile duct stones cause jaundice, how it is diagnosed, and how it is treated.

The Biliary System: A Brief Anatomy

To understand CBD stones and jaundice, it helps to understand the biliary system:

• Liver: Produces bile continuously (600–1,000 ml per day)
• Hepatic ducts: Carry bile from the liver
• Common hepatic duct: Formed by the junction of the left and right hepatic ducts
• Cystic duct: Connects the gallbladder to the common hepatic duct
• Common bile duct (CBD): Formed by the junction of the common hepatic duct and cystic duct; carries bile to the duodenum
• Ampulla of Vater: The opening of the CBD into the duodenum, shared with the pancreatic duct
• Sphincter of Oddi: The muscular valve controlling bile flow into the intestine

When a gallstone lodges in the CBD, it obstructs bile flow from the liver to the intestine. This obstruction causes bile to back up into the liver and bloodstream, producing the characteristic features of obstructive jaundice.

What Are CBD Stones?

CBD stones (choledocholithiasis) are gallstones that have migrated from the gallbladder into the common bile duct. They occur in 10–15% of patients with gallbladder stones.

Types of CBD Stones

Primary CBD stones form directly in the bile duct (not from the gallbladder). They are typically brown pigment stones associated with bile duct infection (cholangitis) or biliary stasis from strictures.

Secondary CBD stones (more common) migrate from the gallbladder into the CBD. They are typically cholesterol or mixed stones.

How Stones Migrate from Gallbladder to CBD

Gallstones can pass through the cystic duct into the CBD when:

• The stone is small enough to pass through the cystic duct (usually <5 mm)
• The cystic duct is dilated (from inflammation or previous stone passage)
• Increased gallbladder pressure forces stones through the cystic duct

Once in the CBD, stones may:

• Pass spontaneously into the duodenum (especially small stones)
• Become lodged in the CBD, causing obstruction
• Become lodged at the ampulla of Vater, obstructing both the bile duct and pancreatic duct

Understanding Jaundice from CBD Stones

Jaundice occurs when bilirubin — a yellow pigment produced from the breakdown of haemoglobin — accumulates in the blood and tissues. Normally, bilirubin is processed by the liver and excreted in bile into the intestine.

The Mechanism of Obstructive Jaundice

When a CBD stone obstructs bile flow:

1. Bile backs up in the liver (cholestasis)

2. Bilirubin cannot be excreted into the intestine

3. Conjugated bilirubin (water-soluble) leaks back into the bloodstream

4. Bilirubin accumulates in the skin and eyes → jaundice

5. Bilirubin is excreted in the urine → dark urine (tea-coloured)

6. Without bile in the intestine → pale, clay-coloured stools

7. Bile salts accumulate in the skin → itching (pruritus)

The Progression of Jaundice

Jaundice from CBD stones typically develops over 24–72 hours. The sequence is:

1. Icteric sclerae — yellowing of the whites of the eyes (first sign, visible when bilirubin >2 mg/dL)

2. Skin jaundice — visible when bilirubin >3 mg/dL

3. Dark urine — appears early, often before skin jaundice is noticeable

4. Pale stools — appear as bile flow to the intestine is reduced

5. Pruritus — itching from bile salt deposition in the skin

Complications of CBD Stones

Acute Cholangitis

The most serious complication of CBD stones is acute cholangitis — bacterial infection of the obstructed bile duct. Bacteria (usually E. coli, Klebsiella, Enterococcus) ascend from the intestine into the stagnant, obstructed bile.

Charcot's Triad (classic presentation):

1. Right upper quadrant pain

2. Fever with rigors (shaking chills)

3. Jaundice

Reynolds' Pentad (severe cholangitis — life-threatening):

4. Hypotension (septic shock)

5. Confusion or altered consciousness

Severe cholangitis has a mortality rate of 10–30% without prompt treatment. It requires immediate hospitalisation, IV antibiotics, and urgent ERCP to decompress the bile duct.

Gallstone Pancreatitis

When a stone lodges at the ampulla of Vater, it can obstruct the pancreatic duct as well as the bile duct, triggering acute pancreatitis. This presents with severe epigastric pain radiating to the back, nausea, vomiting, and elevated serum amylase/lipase.

Secondary Biliary Cirrhosis

Prolonged bile duct obstruction (weeks to months) can cause secondary biliary cirrhosis — irreversible scarring of the liver. This is rare with modern prompt treatment but emphasises the importance of early diagnosis and treatment.

Diagnosis of CBD Stones

Blood Tests

• Liver function tests (LFTs): Elevated bilirubin (conjugated), ALP, GGT, and ALT/AST
• Full blood count: Elevated WBC in cholangitis
• Coagulation studies: Prolonged PT/INR in severe obstruction (liver produces clotting factors)
• Serum amylase/lipase: Elevated in gallstone pancreatitis
• Blood cultures: Positive in 50–80% of cholangitis cases

Ultrasound Abdomen

Ultrasound is the first-line investigation. It can detect:

• Gallbladder stones (>95% sensitivity)
• Dilated CBD (>8 mm suggests obstruction)
• Dilated intrahepatic bile ducts
• CBD stones (only 50–60% sensitivity — CBD stones are often missed on ultrasound)

MRCP (Gold Standard for CBD Stones)

MRCP provides detailed imaging of the entire biliary tree without radiation or contrast injection. Sensitivity for CBD stones >5 mm approaches 95%. It is the investigation of choice when CBD stones are suspected but not confirmed on ultrasound.

CT Scan

CT is less sensitive than MRCP for CBD stones but is useful for assessing complications (pancreatitis, abscess, perforation).

Endoscopic Ultrasound (EUS)

EUS is the most sensitive investigation for small CBD stones (<5 mm) that may be missed by MRCP. It is performed by passing an ultrasound probe through the mouth into the duodenum.

Treatment of CBD Stones

ERCP (First-Line Treatment)

ERCP is the gold-standard treatment for CBD stones. It removes stones non-surgically using a flexible endoscope passed through the mouth.

The ERCP procedure:

1. Endoscope passed through mouth to duodenum

2. Bile duct cannulated and contrast injected (cholangiogram)

3. Sphincterotomy performed (small cut to widen bile duct opening)

4. Stones removed using balloon catheter or Dormia basket

5. Completion cholangiogram confirms complete clearance

Success rate: >90% in a single session. Large stones (>15 mm) may require mechanical lithotripsy.

Laparoscopic CBD Exploration

In some centres, CBD stones are removed laparoscopically at the same time as cholecystectomy (laparoscopic CBD exploration). This avoids the need for a separate ERCP procedure and is preferred in patients with multiple CBD stones or when ERCP is not available.

After ERCP: Cholecystectomy

ERCP removes CBD stones but not the gallbladder. Without cholecystectomy, CBD stones recur in 10–15% of patients per year. Laparoscopic cholecystectomy is recommended within 2–6 weeks of successful ERCP.

When to Seek Urgent Care

Go to A&E immediately if you develop:

• Jaundice (yellow skin or eyes) — especially with fever and abdominal pain
• Fever with rigors and right upper quadrant pain (Charcot's triad — cholangitis)
• Confusion or low blood pressure with fever and jaundice (Reynolds' pentad — life-threatening)
• Severe epigastric pain radiating to the back with vomiting (gallstone pancreatitis)

Emergency contact: Call +91 80889 54804 or go to the nearest A&E.

*Medically reviewed by Dr. Adarsh M Patil, MBBS, MS (General Surgery), Fellowship in Advanced Laparoscopy & Bariatric Surgery (Belgium). Consultant General & Laparoscopic Surgeon, Apollo Clinic Indiranagar, Bangalore.*