Primary Sclerosing Cholangitis (PSC)

1. Overview

Primary Sclerosing Cholangitis (PSC) is a chronic, progressive cholestatic liver disease characterised by inflammation, fibrosis, and multifocal stricturing of the intrahepatic and extrahepatic bile ducts. [1] The etiology remains incompletely understood, but involves complex interactions between genetic susceptibility, immune dysregulation, and gut-liver axis dysfunction. [2]

PSC is distinguished by its strong association with inflammatory bowel disease (IBD), particularly ulcerative colitis (UC), which is present in approximately 70-80% of patients with PSC. [3] Conversely, the prevalence of PSC in patients with IBD is 2.16%, with higher rates in UC (2.47%) compared to Crohn's disease (0.96%). [3]

The disease carries significant morbidity and mortality due to progressive biliary fibrosis leading to cirrhosis and a markedly elevated risk of cholangiocarcinoma (10-20% lifetime risk). [4] There is currently no proven medical therapy to halt or reverse disease progression, making liver transplantation the only curative option for end-stage disease. [5] Recognition of PSC, appropriate surveillance for malignancies, and timely transplant referral are critical to improving outcomes in this challenging condition.

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2. Epidemiology

Incidence and Prevalence

• Geographic Variation: Highest prevalence in Northern Europe and North America; lowest in Southeast Asia [6,7]
• Rising Incidence: Temporal increases observed in Europe and North America over the past 3 decades [7]

Demographics

Association with IBD

Key Clinical Pearls:

• PSC-IBD has a distinctive phenotype: extensive colitis (pancolitis), right-sided disease, rectal sparing, and backwash ileitis are more common
• IBD in PSC may be clinically quiescent or have milder symptoms
• All patients with PSC require colonoscopy to screen for IBD, even if asymptomatic [1]

Risk Factors

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3. Aetiology and Pathophysiology

Aetiology: Multifactorial Model

The pathogenesis of PSC is multifactorial and remains incompletely understood. Current evidence suggests an interplay between:

1. Genetic Susceptibility [2]

   • Strong HLA associations (HLA-DRB103, HLA-B08, HLA-DRB1*13)
   • Over 20 non-HLA risk loci identified (e.g., MST1, MMEL1, GPR35)
   • Familial clustering suggests polygenic inheritance

2. Immune Dysregulation [2,10]

   • Aberrant T-cell and B-cell responses
   • Loss of immune tolerance to biliary epithelium
   • Increased gut-homing lymphocyte trafficking to liver via integrin-MAdCAM-1 interaction
   • Elevated atypical perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) in 65-80% (not pathogenic)

3. Gut-Liver Axis Dysfunction [8,10]

   • Portal vein delivers gut-derived bacterial products to liver
   • Increased intestinal permeability in IBD allows bacterial translocation
   • Dysbiosis alters bile acid metabolism and immune signaling
   • Hypothesis: aberrant gut microbiome triggers cholangiocyte injury in genetically susceptible individuals

4. Environmental Factors

   • No specific infectious or toxic trigger identified
   • Smoking appears protective (inverse association with PSC)

Pathophysiology: Biliary Injury Cascade

Cellular and Molecular Mechanisms

Phase 1: Cholangiocyte Injury

• Immune-mediated attack on biliary epithelial cells (cholangiocytes)
• Cholangiocyte senescence and apoptosis
• Release of damage-associated molecular patterns (DAMPs)

Phase 2: Periductal Inflammation

• Lymphocytic infiltration (CD4+ and CD8+ T cells)
• Recruitment of macrophages and neutrophils
• Cytokine release (TNF-α, IFN-γ, IL-17)

Phase 3: Fibrosis

• Hepatic stellate cell activation
• Myofibroblast differentiation and collagen deposition
• Characteristic "onion-skin" periductal fibrosis (concentric rings of fibrous tissue around bile ducts)

Phase 4: Stricture Formation

• Progressive fibrotic obliteration of bile ducts
• Multifocal strictures (alternating with normal or dilated segments)
• Bile duct loss (ductopenia) in advanced disease

Phase 5: Cholestasis and Secondary Biliary Cirrhosis

• Impaired bile flow leads to accumulation of toxic bile acids
• Hepatocyte injury and portal fibrosis
• Progression to cirrhosis and portal hypertension

Histopathology

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4. Clinical Presentation

PSC has a highly variable clinical course, ranging from asymptomatic biochemical abnormalities to end-stage liver disease.

Symptoms

Physical Examination Findings

Clinical Phenotypes

1. Small Duct PSC (5-10% of cases)

• Normal cholangiography (MRCP/ERCP)
• Cholestatic LFTs and histological features of PSC on biopsy
• Better prognosis than large duct PSC
• Lower cholangiocarcinoma risk

2. PSC-Autoimmune Hepatitis (AIH) Overlap Syndrome (5-10%)

• Features of both PSC (biliary strictures) and AIH (elevated transaminases, hypergammaglobulinemia, positive ANA/SMA)
• May respond to immunosuppression (for AIH component)
• Diagnosis requires liver biopsy

Episodes of Acute Bacterial Cholangitis

Charcot's Triad: Fever, right upper quadrant pain, jaundice

Reynolds' Pentad: Charcot's triad + hypotension + confusion (severe cholangitis)

Triggers:

• Dominant stricture causing bile stasis
• Bacterial superinfection (E. coli, Klebsiella, Enterococcus)
• Post-ERCP (instrumentation increases risk)

Management: Urgent IV antibiotics, biliary drainage (ERCP), supportive care

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5. Differential Diagnosis

Critical Differentiation: PSC vs. IgG4-Related Cholangitis

• IgG4-related disease is steroid-responsive (PSC is not)
• All suspected PSC should have serum IgG4 measured [11]
• Long-segment biliary strictures and pancreatic involvement favor IgG4-disease
• Tissue diagnosis (biopsy with IgG4 immunostaining) may be required

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6. Investigations

Biochemistry

Autoantibodies

Imaging

MRCP (Magnetic Resonance Cholangiopancreatography)

Gold Standard Non-Invasive Diagnostic Test [1]

Classic Findings:

1. "Beads-on-a-String" Appearance: Multifocal strictures alternating with normal or slightly dilated segments (pathognomonic)
2. Multifocal Strictures: Short, band-like strictures affecting intrahepatic and/or extrahepatic bile ducts
3. Pruning of Peripheral Ducts: Loss of visualization of small peripheral intrahepatic ducts (ductopenia)
4. Diverticular Out-Pouchings: Small out-pouchings between strictures

Advantages of MRCP:

• Non-invasive (no radiation, no contrast required)
• High sensitivity and specificity (~85-90% each)
• Allows visualization of entire biliary tree
• Can detect early changes before ERCP

Limitations:

• Cannot distinguish benign stricture from cholangiocarcinoma
• May miss small duct PSC (small intrahepatic ducts below resolution)

ERCP (Endoscopic Retrograde Cholangiopancreatography)

Historically the gold standard, now reserved for therapeutic intervention [1]:

• Dominant stricture dilatation (balloon dilatation ± short-term stenting)
• Biliary brushings/cytology to exclude cholangiocarcinoma
• Stone extraction (rare in PSC)

Risks: Pancreatitis (5-10%), cholangitis (especially in PSC), bleeding, perforation

When to Perform ERCP:

• Dominant stricture on MRCP (need tissue diagnosis to exclude malignancy)
• Clinical deterioration with worsening cholestasis
• Acute bacterial cholangitis requiring drainage

Ultrasound and CT

Not diagnostic, but useful for:

• Initial evaluation of abnormal LFTs (exclude biliary dilatation, gallstones)
• Surveillance for hepatocellular carcinoma (if cirrhotic)
• Assessment of complications (ascites, portal vein thrombosis)

Transient Elastography (FibroScan)

• Assess degree of hepatic fibrosis non-invasively
• Limited utility in PSC (less validated than in viral hepatitis/NAFLD)

Liver Biopsy

Not routinely required for diagnosis (MRCP is diagnostic in large duct PSC) [1]

Indications:

1. Small Duct PSC: Normal MRCP but cholestatic LFTs and clinical suspicion
2. PSC-AIH Overlap: Elevated transaminases, hypergammaglobulinemia
3. Staging: Assess degree of fibrosis when non-invasive markers inconclusive
4. IgG4-Related Disease: Tissue diagnosis with IgG4 immunostaining

Histological Features:

• Onion-skin periductal fibrosis (pathognomonic but present in only 20-30% of biopsies)
• Bile duct damage and loss (ductopenia)
• Portal inflammation and fibrosis

Colonoscopy

MANDATORY in all patients with PSC [1,12]

Rationale:

• 70-80% of PSC patients have IBD (many asymptomatic)
• PSC-IBD patients have markedly elevated colorectal cancer (CRC) risk

Surveillance Protocol:

• Baseline colonoscopy at PSC diagnosis
• If IBD diagnosed: Annual surveillance colonoscopy with random biopsies (high CRC risk) [12]
• If no IBD: Repeat colonoscopy if symptoms develop or consider repeat every 5 years

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7. Classification and Staging

Amsterdam Classification (Large Duct vs. Small Duct PSC)

Note: Small duct PSC may progress to large duct PSC in 10-20% over time

Prognostic Models

1. Mayo Risk Score (Original 1989, Revised 2000)

Variables:

• Age
• Bilirubin
• Albumin
• AST
• History of variceal bleeding

Output: Predicted survival at 1, 2, 5 years

Limitations: Developed pre-MRCP era; less accurate in UDCA-treated patients

2. UK-PSC Risk Score

Variables:

• Alkaline phosphatase (ALP) after 12 months of UDCA
• Albumin
• Platelet count
• AST/ALT ratio
• Variceal bleeding

Output: Predicted transplant-free survival

Advantage: Incorporates treatment response to UDCA

3. Amsterdam-Oxford Model

Most recent model (incorporates liver stiffness, enhanced liver fibrosis score, presence of cirrhosis)

Histological Staging (Ludwig Classification)

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8. Management

General Principles

Critical Recognition: There is NO proven disease-modifying medical therapy for PSC [5,13]

Management focuses on:

1. Symptom control (pruritus, fatigue)
2. Surveillance for complications and malignancies
3. Management of dominant strictures
4. Treatment of concurrent IBD
5. Liver transplantation for end-stage disease

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Medical Management

Ursodeoxycholic Acid (UDCA): The Controversy [5,13]

Standard Dose (13-15 mg/kg/day):

• Improves alkaline phosphatase and bilirubin
• Does NOT improve survival, symptom progression, or transplant-free survival (randomized trials)
• Some centers still prescribe based on biochemical improvement

High Dose (25-30 mg/kg/day):

• May be HARMFUL (increased mortality and adverse events in randomized trial) [13]
• Avoid high-dose UDCA

Current Practice:

• No guideline consensus
• Many centers do NOT routinely prescribe UDCA
• If used, limit to standard dose (13-15 mg/kg/day)

Obeticholic Acid (OCA)

• Farnesoid X receptor (FXR) agonist
• Licensed for PBC, NOT PSC
• Clinical trials in PSC have shown no benefit and potential harm (pruritus)

Immunosuppression

• NOT effective in PSC (unlike autoimmune hepatitis)
• Consider only if PSC-AIH overlap syndrome (requires biopsy confirmation)

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Symptom Management

Pruritus [1]

Stepwise Approach:

1. First-Line: Cholestyramine (4-16 g/day in divided doses)

   • Bile acid sequestrant; binds pruritogenic bile acids in gut
   • Take 4 hours apart from other medications (reduces absorption)
   • Side effects: Constipation, bloating, fat-soluble vitamin deficiency

2. Second-Line: Rifampicin (150-300 mg twice daily)

   • Enzyme inducer; mechanisms unclear
   • Monitor LFTs (hepatotoxicity risk)
   • Drug interactions (reduces efficacy of oral contraceptives, warfarin)

3. Third-Line: Sertraline (50-100 mg daily)

   • SSRI; modulates central opioid pathways
   • May help with concurrent depression/fatigue

4. Fourth-Line: Naltrexone (25-50 mg daily)

   • Opioid antagonist
   • Start low dose (may cause withdrawal-like symptoms initially)

5. Refractory Pruritus:

   • Nasobiliary drainage (temporary)
   • Molecular adsorbent recirculating system (MARS) dialysis
   • Consider liver transplantation if intractable

Fat-Soluble Vitamin Deficiency

Monitor and Replace:

• Vitamin A (night blindness)
• Vitamin D (osteoporosis risk)
• Vitamin E (neuropathy risk)
• Vitamin K (coagulopathy)

Screening: Annual vitamins A, D, E, K levels in cholestatic patients

Metabolic Bone Disease

• DEXA scan at diagnosis and every 2-3 years
• Calcium and Vitamin D supplementation
• Bisphosphonates if osteoporosis (T-score < -2.5)

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Management of Dominant Stricture

Definition: Stenosis of common hepatic duct < 1.5 mm or common bile duct < 2 mm [1]

Clinical Significance:

• Causes progressive cholestasis and cholangitis
• HIGH suspicion for cholangiocarcinoma (difficult to differentiate benign vs. malignant)

Diagnostic Approach:

1. MRCP: Identify and characterize stricture
2. ERCP with Brushings/Biopsy: Obtain tissue for cytology/histology
3. Fluorescence In-Situ Hybridization (FISH): Increases diagnostic yield for malignancy
4. Serum CA 19-9: Elevated in cholangiocarcinoma (but also in cholangitis)
5. EUS-Guided Fine Needle Aspiration (EUS-FNA): If accessible mass lesion

Management:

• Balloon Dilatation ± Short-Term Stenting (if benign): Improves symptoms and cholestasis
• Avoid long-term stents (increase cholangitis risk)
• Cholangiocarcinoma: Discuss at multidisciplinary team meeting; consider resection (if isolated extrahepatic) or liver transplant (if strict criteria met)

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Management of Concurrent IBD [8,12]

Key Principles:

• Treat IBD with standard therapies (5-ASA, immunomodulators, biologics)
• Control of intestinal inflammation does NOT improve PSC (they behave independently)
• Annual colonoscopy mandatory (high CRC risk)

IBD-Specific Considerations in PSC:

• Right-sided colitis and rectal sparing more common
• IBD may persist or develop even after liver transplantation
• Colectomy for refractory IBD does NOT improve PSC

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Surveillance for Malignancies

Cholangiocarcinoma (CCA) [4]

Lifetime Risk: 10-20% (400x general population risk)

Risk Factors:

• Long duration of PSC
• Presence of dominant stricture
• Inflammatory bowel disease
• Smoking
• Alcohol use

Surveillance Strategy (No proven effective protocol):

Diagnosis is Challenging:

• Cytology/histology sensitivity is low (30-50%)
• FISH analysis improves sensitivity to 50-60%
• High clinical suspicion required

Management:

• Resection (if isolated extrahepatic CCA, no cirrhosis)
• Liver transplantation (if meets strict criteria: unresectable perihilar CCA < 3 cm, no metastases, neoadjuvant chemoradiation protocol)
• Palliative chemotherapy

Colorectal Cancer (CRC) [12]

Risk: PSC-UC patients have 4-5x higher CRC risk than UC alone

Surveillance:

• Annual colonoscopy with random biopsies (every 10 cm, 4-quadrant) starting at IBD diagnosis
• Continue surveillance even after liver transplantation

Gallbladder Polyps and Cancer

Risk: Increased gallbladder carcinoma risk in PSC (2-3%)

Surveillance: Annual ultrasound

Cholecystectomy Indications:

• Gallbladder polyp ≥8 mm
• Any gallbladder mass lesion
• Porcelain gallbladder (calcified wall)

Hepatocellular Carcinoma (HCC)

Risk: Lower than in other cirrhosis etiologies, but still present

Surveillance (if cirrhotic): Ultrasound + AFP every 6 months

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9. Liver Transplantation [14]

Only Curative Treatment for PSC

Indications

Standard Liver Transplant Indications:

• Decompensated cirrhosis (ascites, variceal bleeding, hepatic encephalopathy)
• Model for End-Stage Liver Disease (MELD) score ≥15
• Intractable pruritus (significantly impaired quality of life)
• Recurrent bacterial cholangitis
• Hepatocellular carcinoma (within Milan criteria)

PSC-Specific Indication:

• Cholangiocarcinoma (if meets strict criteria: perihilar CCA < 3 cm, no metastases, neoadjuvant chemoradiation, exploratory laparotomy negative)

Outcomes

Post-Transplant Considerations

• IBD persists or may develop de novo after transplant
• Continue CRC surveillance (annual colonoscopy)
• Lifelong immunosuppression (tacrolimus, mycophenolate)
• Monitor for recurrent PSC (rising ALP, new strictures on MRCP)

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10. Complications

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11. Prognosis

Natural History

Prognostic Factors

Poor Prognostic Indicators:

• Age 60 at diagnosis
• Jaundice (elevated bilirubin)
• Hepatosplenomegaly
• Variceal bleeding
• Dominant stricture
• High Mayo risk score

Favorable Factors:

• Asymptomatic at diagnosis
• Normal bilirubin
• Small duct PSC (better prognosis than large duct)

Causes of Death

1. Liver Failure (cirrhosis, decompensation)
2. Cholangiocarcinoma (poor prognosis; median survival 6-12 months untreated)
3. Colorectal Cancer (if concurrent IBD)
4. Sepsis (recurrent cholangitis)
5. Complications of Liver Transplantation

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12. Prevention and Screening

Primary Prevention

No known primary prevention (etiology unknown)

Screening

Who to Screen for PSC:

• Patients with IBD (particularly UC) and abnormal LFTs (elevated ALP)
• First-degree relatives with PSC (10-100x increased risk)

Who to Screen for IBD in Diagnosed PSC:

• All patients with PSC (70-80% have IBD)
• Colonoscopy at PSC diagnosis

Who to Screen for Malignancies in PSC:

• Cholangiocarcinoma: Annual MRCP and CA 19-9 (all PSC patients)
• Colorectal Cancer: Annual colonoscopy (if IBD present)
• Gallbladder Cancer: Annual ultrasound (all PSC patients)
• Hepatocellular Carcinoma: Ultrasound + AFP every 6 months (if cirrhotic)

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13. Key Guidelines

Guideline Consensus:

• MRCP is diagnostic gold standard
• No proven disease-modifying therapy (UDCA does NOT improve outcomes)
• Mandatory colonoscopy at diagnosis and annual surveillance if IBD
• High index of suspicion for cholangiocarcinoma (dominant strictures)
• Liver transplantation is only curative treatment

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14. Patient and Layperson Explanation

What is Primary Sclerosing Cholangitis (PSC)?

PSC is a disease of the bile ducts, the tubes that carry bile from your liver to your intestines. In PSC, these bile ducts become scarred and narrowed, which blocks the flow of bile. Over time, this can damage your liver.

Who gets PSC?

• PSC is rare, affecting about 1 in 10,000 people
• It is more common in men (2 out of 3 patients are male)
• Most people are diagnosed between ages 30-40
• 7-8 out of 10 people with PSC also have inflammatory bowel disease (usually ulcerative colitis)

What causes PSC?

The exact cause is unknown. It is thought to involve:

• Genetic factors (runs in families in some cases)
• Immune system dysfunction (your immune system attacks bile ducts)
• Gut-liver connection (bacteria or toxins from the gut may trigger liver inflammation)

What are the symptoms?

Many people have no symptoms at first. When symptoms occur, they may include:

• Tiredness (very common)
• Itching (pruritus) – can be severe
• Yellow skin and eyes (jaundice)
• Abdominal pain (right upper side)
• Diarrhea or bloody stool (if you have inflammatory bowel disease)

How is PSC diagnosed?

• Blood tests: High alkaline phosphatase (a liver enzyme)
• MRCP scan: A special MRI scan that shows your bile ducts (shows "beads-on-a-string" appearance)
• Colonoscopy: To check if you have inflammatory bowel disease

Is there a cure?

Unfortunately, there is no medication that can cure or stop PSC from getting worse. Treatments focus on:

• Managing symptoms (e.g., medications for itching)
• Monitoring for complications (e.g., cancer screening)
• Liver transplant (the only cure, for advanced disease)

What are the risks and complications?

1. Liver failure: PSC can lead to cirrhosis (scarring of the liver) and liver failure over 10-15 years
2. Bile duct cancer (cholangiocarcinoma): 10-20 out of 100 people with PSC develop this cancer
3. Bowel cancer: If you have inflammatory bowel disease, your risk of colon cancer is higher
4. Infections: Bile duct blockages can cause infections (cholangitis)

What monitoring do I need?

• Regular blood tests to check liver function
• Annual MRCP or ultrasound scan to look for bile duct changes or cancer
• Annual colonoscopy (if you have inflammatory bowel disease) to screen for colon cancer

What is the outlook?

• PSC is a long-term, slowly progressive disease
• Progression varies widely: some people remain stable for years; others progress faster
• Average time to liver transplant or liver failure is 10-15 years from diagnosis
• Liver transplant has good success rates (80-85% survive at least 5 years)

What should I do?

• Follow up regularly with your gastroenterologist and hepatologist
• Attend all surveillance appointments (scans, colonoscopies)
• Report any new symptoms promptly (especially jaundice, severe pain, fever)
• Avoid alcohol (may worsen liver damage)
• Ask about liver transplant referral if your liver disease progresses

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15. Common Exam Questions

For MRCP and Postgraduate Examinations

1. What is the most common extrahepatic association of PSC?

• Answer: Inflammatory bowel disease, particularly ulcerative colitis (present in 70-80% of PSC patients) [3]

2. What is the characteristic imaging finding of PSC on MRCP?

• Answer: "Beads-on-a-string" appearance – multifocal strictures alternating with normal or dilated segments of the intrahepatic and extrahepatic bile ducts [1]

3. What is the hallmark biochemical abnormality in PSC?

• Answer: Elevated alkaline phosphatase (ALP), typically 3-10 times the upper limit of normal, with a cholestatic pattern of LFTs [1]

4. Is there a proven disease-modifying medical therapy for PSC?

• Answer: No. Ursodeoxycholic acid (UDCA) improves liver biochemistry but does NOT improve survival, transplant-free survival, or symptom progression. High-dose UDCA (25 mg/kg) may be harmful. [5,13]

5. What is the lifetime risk of cholangiocarcinoma in PSC?

• Answer: 10-20% (approximately 400 times higher than the general population) [4]

6. How is PSC differentiated from primary biliary cholangitis (PBC)?

• PSC: Male predominance, IBD association, biliary strictures on MRCP, AMA negative, atypical p-ANCA positive
• PBC: Female predominance, AMA positive (95%), intrahepatic small bile duct destruction, NO strictures on MRCP [1]

7. What surveillance is required for PSC patients with concurrent IBD?

• Answer: Annual colonoscopy with random biopsies due to markedly elevated colorectal cancer risk (4-5x higher than UC alone) [12]

8. What defines a "dominant stricture" in PSC, and why is it important?

• Answer: Stenosis of the common hepatic duct < 1.5 mm or common bile duct < 2 mm. Important because it causes progressive cholestasis, cholangitis, and has high suspicion for cholangiocarcinoma (requires ERCP with brushings/cytology) [1]

9. What is the only curative treatment for PSC?

• Answer: Liver transplantation. 5-year survival post-transplant is 80-85%. However, PSC can recur in the graft in 20-25% of patients. [14]

10. How does PSC-associated IBD differ from classical IBD?

• Answer: PSC-IBD has a distinct phenotype: more extensive colitis (pancolitis), right-sided predominance, rectal sparing, backwash ileitis. IBD symptoms may be mild or quiescent despite extensive disease. [8]

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16. Viva Voce Points

Opening Statement

"Primary sclerosing cholangitis is a chronic, progressive cholestatic liver disease characterised by immune-mediated inflammation and fibrosis of the intrahepatic and extrahepatic bile ducts, leading to multifocal biliary strictures, cirrhosis, and a significantly elevated risk of cholangiocarcinoma. It has a strong association with inflammatory bowel disease, particularly ulcerative colitis."

Key Facts to Mention

Epidemiology:

• Incidence: 0.87 per 100,000; Prevalence: 13.53 per 100,000 [6]
• Male predominance 2:1; peak age 30-40 years
• 70-80% of PSC patients have IBD (mostly UC) [3]
• 2.47% of UC patients have PSC [3]

Pathophysiology:

• Multifactorial: genetic susceptibility (HLA-DRB103, HLA-B08), immune dysregulation, gut-liver axis dysfunction
• Characteristic histology: onion-skin periductal fibrosis, bile duct damage, ductopenia

Diagnosis:

• Elevated ALP (3-10x ULN) – hallmark biochemical finding
• MRCP gold standard: "beads-on-a-string" multifocal strictures
• Atypical p-ANCA positive 65-80%; AMA negative (differentiates from PBC)
• Mandatory colonoscopy to screen for IBD

Management:

• No proven disease-modifying therapy
• UDCA improves biochemistry but NOT outcomes
• Symptom management: cholestyramine (pruritus), vitamin supplementation
• Dominant stricture: ERCP + brushings (exclude cholangiocarcinoma)
• Liver transplantation: only curative treatment (5-year survival 80-85%)

Complications:

• Cholangiocarcinoma: 10-20% lifetime risk [4]
• Colorectal cancer: annual colonoscopy if IBD [12]
• Cirrhosis, portal hypertension, recurrent cholangitis

Differentials:

• PBC: AMA positive, NO strictures on MRCP, female, intrahepatic small duct disease
• IgG4-related cholangitis: Elevated serum IgG4, steroid-responsive
• Secondary sclerosing cholangitis: Identifiable cause (stones, surgery, ischemia)

Common Viva Scenarios

Scenario 1: "A 35-year-old man with ulcerative colitis is found to have an ALP of 450 U/L. How would you investigate?"

Model Answer: "This patient has cholestatic liver biochemistry in the context of IBD, which raises concern for PSC. I would:

1. Check full liver function tests, including GGT, bilirubin, transaminases, albumin, and coagulation
2. Measure autoantibodies: AMA (to exclude PBC), atypical p-ANCA, ANA, SMA
3. Measure serum IgG4 (to exclude IgG4-related cholangitis)
4. Arrange MRCP to visualize the biliary tree (looking for multifocal strictures – 'beads-on-a-string')
5. If MRCP confirms PSC, stage liver fibrosis (FibroScan or FIB-4 score)
6. Ensure colonoscopy surveillance is up to date (annual in PSC-IBD due to high CRC risk)"

Scenario 2: "A patient with established PSC presents with worsening jaundice and weight loss. What are your concerns and next steps?"

Model Answer: "My primary concern is cholangiocarcinoma, which occurs in 10-20% of PSC patients and often presents with dominant stricture, progressive jaundice, and weight loss. I would:

1. Repeat liver biochemistry (bilirubin, ALP) and check CA 19-9 (elevated in CCA, but also cholangitis)
2. Arrange urgent MRCP to assess for new dominant stricture or mass lesion
3. Refer for ERCP with biliary brushings and/or biopsy for cytology and FISH analysis
4. Consider EUS-guided FNA if accessible mass
5. Exclude other causes: cholangitis (fever, cultures), decompensated cirrhosis (ascites, encephalopathy)
6. Discuss at hepatobiliary MDT for management plan (resection, transplant, or palliative care)"

Scenario 3: "What is the role of UDCA in PSC?"

Model Answer: "Ursodeoxycholic acid at standard doses (13-15 mg/kg/day) improves liver biochemistry, specifically ALP and bilirubin, but does NOT improve survival, transplant-free survival, or histological progression based on randomized controlled trials. High-dose UDCA (25-30 mg/kg/day) was studied in a trial but was stopped early due to increased adverse events and mortality in the UDCA arm. Current guidelines do not recommend UDCA as a disease-modifying therapy, though some centers still use standard doses based on biochemical improvement. There is no consensus." [5,13]

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17. Common Mistakes and Pitfalls

❌ Mistake 1: Assuming UDCA will slow PSC progression

• Reality: UDCA improves biochemistry only; NO survival benefit [5,13]

❌ Mistake 2: Not screening PSC patients for IBD

• Reality: 70-80% have IBD; colonoscopy is mandatory at PSC diagnosis [3]

❌ Mistake 3: Assuming control of IBD will improve PSC

• Reality: PSC and IBD behave independently; treating IBD does NOT improve liver disease [8]

❌ Mistake 4: Failing to suspect cholangiocarcinoma in a dominant stricture

• Reality: Dominant stricture = cancer until proven otherwise; requires urgent ERCP + brushings [4]

❌ Mistake 5: Confusing PSC with PBC

• Key Difference: PBC = AMA positive, NO strictures on MRCP; PSC = AMA negative, strictures on MRCP [1]

❌ Mistake 6: Not performing annual colonoscopy in PSC-IBD

• Reality: PSC-UC has 4-5x higher CRC risk than UC alone; annual surveillance essential [12]

❌ Mistake 7: Using immunosuppression for PSC

• Reality: Immunosuppression is NOT effective in PSC (unlike AIH); only consider if PSC-AIH overlap [1]

❌ Mistake 8: Missing IgG4-related cholangitis

• Reality: IgG4-disease is steroid-responsive (unlike PSC); always measure serum IgG4 [11]

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18. References

1. European Association for the Study of the Liver. EASL Clinical Practice Guidelines: Management of cholestatic liver diseases. J Hepatol. 2009;51(2):237-267. doi:10.1016/j.jhep.2009.04.009

2. Trivedi PJ, Hirschfield GM, Adams DH, Vierling JM. Immunopathogenesis of Primary Biliary Cholangitis, Primary Sclerosing Cholangitis and Autoimmune Hepatitis: Themes and Concepts. Gastroenterology. 2024;166(6):995-1019. doi:10.1053/j.gastro.2024.01.049

3. Barberio B, Massimi D, Cazzagon N, et al. Prevalence of Primary Sclerosing Cholangitis in Patients With Inflammatory Bowel Disease: A Systematic Review and Meta-analysis. Gastroenterology. 2021;161(6):1865-1877. doi:10.1053/j.gastro.2021.08.032

4. Karlsen TH, Folseraas T, Thorburn D, Vesterhus M. Primary sclerosing cholangitis - a comprehensive review. J Hepatol. 2017;67(6):1298-1323. doi:10.1016/j.jhep.2017.07.022

5. Lindor KD, Kowdley KV, Harrison ME. ACG Clinical Guideline: Primary Sclerosing Cholangitis. Am J Gastroenterol. 2015;110(5):646-659. doi:10.1038/ajg.2015.112

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