Question

A chronic cholestatic liver disorder causes progressive inflammation, scarring, and narrowing of the intrahepatic and extrahepatic bile ducts. Which condition is it most strongly linked with?

A. Primary biliary cholangitis
B. Ileal-predominant inflammatory bowel disease
C. Chronic hepatitis B infection
D. Ulcerative colitis
E. Autoimmune gluten-sensitive enteropathy

Answer

D. Ulcerative colitis

Detailed explanation

Primary sclerosing cholangitis is most strongly associated with ulcerative colitis.

PSC is a chronic cholestatic liver disease characterised by inflammation, fibrosis, and stricturing of both intrahepatic and extrahepatic bile ducts. The classic association is with inflammatory bowel disease, especially ulcerative colitis.

Important exam numbers:

• Around 70–80% of patients with PSC have ulcerative colitis.
• Around 4–5% of patients with ulcerative colitis develop PSC.
• Crohn’s disease can be associated, but much less commonly.

PSC often presents with cholestatic liver biochemistry:

• Raised ALP and GGT
• Later raised bilirubin
• Pruritus
• Jaundice
• Fatigue
• Right upper quadrant discomfort

The investigation of choice is MRCP, which shows multifocal strictures and dilatations of the bile ducts, giving the classic “beaded” appearance.

PSC is clinically important because it increases the risk of:

• Cholangiocarcinoma
• Colorectal cancer, especially in patients with ulcerative colitis
• Gallbladder carcinoma
• Progressive biliary cirrhosis and liver failure

Why the other options are wrong

A. Primary biliary cholangitis
Primary biliary cholangitis is a separate autoimmune cholestatic liver disease. It mainly affects small intrahepatic bile ducts and is associated with anti-mitochondrial antibodies. PSC affects intrahepatic and extrahepatic ducts and is classically linked to ulcerative colitis.

B. Ileal-predominant inflammatory bowel disease
This refers to Crohn’s disease. Crohn’s disease can be associated with PSC, but the association is much weaker than with ulcerative colitis.

C. Chronic hepatitis B infection
Hepatitis B primarily causes hepatocellular inflammation and can lead to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. It is not a classic association of PSC.

E. Autoimmune gluten-sensitive enteropathy
This refers to coeliac disease. Although coeliac disease is autoimmune, it is not strongly associated with PSC. Coeliac disease mainly affects the small intestine and is associated with anti-tTG and anti-endomysial antibodies.

Key exam point

Primary sclerosing cholangitis is strongly associated with ulcerative colitis and causes a beaded appearance of the bile ducts on MRCP.

Very important concept / clinical trap

PSC and PBC are both cholestatic autoimmune-type liver diseases, but they are different conditions.

Feature	PSC	PBC
Full name	Primary sclerosing cholangitis	Primary biliary cholangitis
Ducts affected	Intrahepatic and extrahepatic bile ducts	Small intrahepatic bile ducts
Classic association	Ulcerative colitis	Other autoimmune disease
Antibody	p-ANCA may be positive	Anti-mitochondrial antibody
Imaging	MRCP: beaded ducts	Imaging often less diagnostic
Biopsy	Onion-skin fibrosis	Florid duct lesions
Cancer risk	Cholangiocarcinoma, colorectal cancer	Hepatocellular carcinoma in cirrhosis

Cheat sheet for exam

• PSC = chronic inflammation and fibrosis of intrahepatic and extrahepatic bile ducts.
• Strongest association = ulcerative colitis.
• 70–80% of PSC patients have UC.
• Only around 4–5% of UC patients develop PSC.
• Crohn’s disease association exists but is much weaker.
• Symptoms: pruritus, jaundice, fatigue, RUQ pain.
• Bloods: cholestatic pattern, especially raised ALP and GGT.
• Best diagnostic test: MRCP.
• MRCP finding: multifocal strictures and dilatations producing “beaded” bile ducts.
• ERCP is now mainly used for intervention, not first-line diagnosis.
• Liver biopsy may show onion-skin periductal fibrosis.
• p-ANCA may be positive.
• Complications: cholangiocarcinoma, colorectal cancer, gallbladder cancer, cirrhosis.
• PSC + UC means increased colorectal cancer risk, so colonoscopic surveillance is important.
• No medical therapy reliably stops progression.
• Liver transplant is the definitive treatment for advanced disease.

Flash cards

Q: What inflammatory bowel disease is most strongly associated with PSC?
A: Ulcerative colitis. Around 70–80% of PSC patients have UC.

Q: What is the diagnostic investigation of choice for PSC?
A: MRCP. It shows multifocal strictures and dilatations of the bile ducts.

Q: What is the classic MRCP appearance in PSC?
A: A “beaded” appearance of the bile ducts due to alternating strictures and dilatations.

Q: What pattern of liver function tests is typical in PSC?
A: Cholestatic pattern, with raised ALP and GGT.

Q: Which cancer is classically associated with PSC?
A: Cholangiocarcinoma.

Q: What colorectal complication is increased in patients with PSC and ulcerative colitis?
A: Colorectal cancer.

Q: What biopsy appearance may be seen in PSC?
A: Onion-skin periductal fibrosis.

Q: Which antibody is strongly associated with primary biliary cholangitis rather than PSC?
A: Anti-mitochondrial antibody.

MCQs

1. A 36-year-old man with chronic diarrhoea and intermittent rectal bleeding is found to have raised ALP and GGT. MRCP shows multifocal strictures of the intrahepatic and extrahepatic bile ducts. Which associated condition is most likely?

A. Coeliac disease
B. Ulcerative colitis
C. Wilson disease
D. Chronic hepatitis C
E. Alcohol-related liver disease

Answer: B. Ulcerative colitis

Explanation: PSC is classically associated with ulcerative colitis. The MRCP finding of multifocal strictures involving intrahepatic and extrahepatic ducts is highly suggestive of PSC.

2. Which investigation is now considered the diagnostic test of choice for suspected primary sclerosing cholangitis?

A. Liver biopsy
B. Anti-mitochondrial antibody testing
C. MRCP
D. ERCP
E. Abdominal plain X-ray

Answer: C. MRCP

Explanation: MRCP is non-invasive and demonstrates the characteristic beaded appearance of the bile ducts. ERCP was historically the gold standard but is now mainly used for therapeutic intervention.

3. Which of the following is false regarding primary sclerosing cholangitis?

A. It is associated with ulcerative colitis
B. It may cause cholestatic liver function tests
C. It is associated with cholangiocarcinoma
D. Anti-mitochondrial antibody is usually strongly positive
E. MRCP may show a beaded biliary tree

Answer: D. Anti-mitochondrial antibody is usually strongly positive

Explanation: Anti-mitochondrial antibody is typical of primary biliary cholangitis, not PSC. PSC may be associated with p-ANCA, but there is no single highly specific diagnostic antibody.

4. A patient with ulcerative colitis is diagnosed with PSC. Which additional malignancy risk becomes especially important?

A. Colorectal cancer
B. Testicular cancer
C. Pancreatic neuroendocrine tumour
D. Renal cell carcinoma
E. Thyroid cancer

Answer: A. Colorectal cancer

Explanation: PSC in a patient with ulcerative colitis increases colorectal cancer risk. These patients require careful colonoscopic surveillance.

5. Which histological description is most classically associated with PSC?

A. Interface hepatitis with plasma cells
B. Copper accumulation in hepatocytes
C. Onion-skin periductal fibrosis
D. Mallory-Denk bodies
E. Granulomatous destruction of small ducts

Answer: C. Onion-skin periductal fibrosis

Explanation: PSC can show concentric periductal fibrosis, often described as onion-skin fibrosis. However, biopsy is not usually the first-line diagnostic test.

6. Which of the following best differentiates PSC from primary biliary cholangitis?

A. PSC affects only hepatocytes
B. PSC is strongly associated with anti-mitochondrial antibodies
C. PSC is more strongly associated with ulcerative colitis and affects large bile ducts
D. PSC is caused by chronic hepatitis C
E. PSC is treated definitively with gluten withdrawal

Answer: C. PSC is more strongly associated with ulcerative colitis and affects large bile ducts

Explanation: PSC commonly affects both intrahepatic and extrahepatic bile ducts and is strongly associated with UC. PBC affects small intrahepatic ducts and is associated with AMA.

7. Which of the following is a recognised complication of PSC?

A. Cholangiocarcinoma
B. Medullary thyroid carcinoma
C. Small-cell lung carcinoma
D. Seminoma
E. Phaeochromocytoma

Answer: A. Cholangiocarcinoma

Explanation: PSC significantly increases the risk of cholangiocarcinoma. It also increases the risk of colorectal cancer in patients with ulcerative colitis.

8. A patient has pruritus, jaundice, raised ALP, and MRCP showing biliary strictures. Which antibody may be positive but is not diagnostic?

A. Anti-centromere antibody
B. Anti-CCP antibody
C. p-ANCA
D. Anti-tTG antibody
E. Anti-Jo-1 antibody

Answer: C. p-ANCA

Explanation: p-ANCA may be positive in PSC and ulcerative colitis, but it is not diagnostic. PSC diagnosis is usually made by cholangiographic imaging, especially MRCP.

9. Which of the following is false about ERCP in PSC?

A. It was historically the gold-standard diagnostic test
B. It carries risks such as pancreatitis
C. It has been largely replaced by MRCP for diagnosis
D. It has no role at all in PSC management
E. It may be useful for therapeutic procedures

Answer: D. It has no role at all in PSC management

Explanation: ERCP is no longer the preferred diagnostic test because MRCP is safer and non-invasive. However, ERCP remains useful for interventions such as dilatation or stenting of dominant strictures.

10. A 42-year-old man with ulcerative colitis has fatigue and pruritus. Blood tests show ALP 690 U/L, bilirubin mildly elevated, and ALT only moderately raised. What liver test pattern does this represent?

A. Isolated synthetic failure
B. Cholestatic pattern
C. Pure hepatocellular pattern
D. Haemolytic pattern
E. Nephrotic pattern

Answer: B. Cholestatic pattern

Explanation: PSC typically causes a cholestatic liver enzyme pattern, with disproportionately elevated ALP and GGT compared with transaminases.

Summary for quick exam revision

Primary sclerosing cholangitis is a chronic cholestatic liver disease caused by inflammation, fibrosis, and stricturing of intrahepatic and extrahepatic bile ducts. Its strongest association is ulcerative colitis. Around 70–80% of patients with PSC have ulcerative colitis, but only a small minority of patients with ulcerative colitis develop PSC. Crohn’s disease can also be associated, but much less commonly. PSC usually presents with pruritus, jaundice, fatigue, right upper quadrant pain, and cholestatic liver biochemistry with raised ALP and GGT. The diagnostic investigation of choice is MRCP, which shows multifocal strictures and dilatations producing a classic beaded appearance. ERCP was historically the gold-standard test but is now mainly used for therapeutic intervention because of its complication risk. Liver biopsy has a limited role but may show onion-skin periductal fibrosis. p-ANCA may be positive, but there is no highly specific diagnostic antibody. PSC must be distinguished from primary biliary cholangitis, which affects small intrahepatic ducts and is associated with anti-mitochondrial antibodies. The major complications of PSC are cholangiocarcinoma, gallbladder cancer, progressive biliary cirrhosis, and colorectal cancer in patients with ulcerative colitis. PSC with ulcerative colitis requires careful colorectal cancer surveillance. No medical therapy reliably halts disease progression, and liver transplantation is the definitive treatment for advanced disease.