Hepatobiliary: Primary Sclerosing Cholangitis (PSC)

Primary sclerosing cholangitis (PSC) is a long‑term disease where the bile ducts in and around the liver become inflamed and scarred. It is strongly linked with ulcerative colitis (UC) and is considered an extraintestinal manifestation of inflammatory bowel disease (IBD). PSC is uncommon but serious, because it can silently damage the liver and increase the risk of bile duct and colon cancers, so careful monitoring is important.

Key Takeaways

• PSC is a chronic inflammation and scarring of the bile ducts that often leads to cholestatic liver damage and, over time, cirrhosis. (ncbi.nlm.nih.gov)

• Around 70% of people with PSC also have IBD, most often UC, but only about 2–5% of people with UC develop PSC. (pubmed.ncbi.nlm.nih.gov)

• PSC can be silent and first show up as abnormal liver blood tests, especially raised alkaline phosphatase, on routine monitoring. (en.wikipedia.org)

• Having both PSC and IBD greatly increases colorectal cancer risk, so high‑quality colonoscopy is recommended every 1–2 years starting as soon as PSC is diagnosed. (pubmed.ncbi.nlm.nih.gov)

• People with PSC need regular liver blood tests and bile duct imaging to track disease progression and to screen for bile duct and gallbladder cancers. (guidelinecentral.com)

What is Primary Sclerosing Cholangitis?

PSC is a disease of the bile ducts, the small tubes that carry bile from the liver to the intestine. In PSC, these ducts become inflamed, then scarred and narrowed. Over time, many short narrowings and widenings appear along the ducts, creating a “beaded” look on imaging. (ncbi.nlm.nih.gov)

Because bile cannot flow normally, bile salts and toxins build up in the liver. This long‑term blockage can cause chronic cholestatic liver injury, fibrosis, and eventually cirrhosis and liver failure in many people. PSC is thought to involve the immune system, genes, and environmental factors, but there is no single known cause. (ncbi.nlm.nih.gov)

PSC is rare. It is seen more often in people of Northern European ancestry and more often in men than women. Most diagnoses occur in early to middle adulthood, although PSC can appear at any age. (en.wikipedia.org)

PSC is considered an extraintestinal manifestation of IBD because it affects the liver and bile ducts, not the bowel itself, yet is tightly associated with UC and, less often, Crohn’s disease.

How PSC and IBD, Especially UC, Are Linked

The connection between PSC and IBD runs in both directions:

• Among people with PSC, about 70% have IBD, and more than half have UC. (pubmed.ncbi.nlm.nih.gov)

• Among people with IBD, PSC is much less common. Large pooled studies suggest PSC occurs in about 2–3% of people with UC and about 1% of those with Crohn’s disease overall. (pubmed.ncbi.nlm.nih.gov)

• PSC is more likely in people with extensive or pancolitis (disease affecting the whole colon) than in those with disease limited to the rectum or left side. (pubmed.ncbi.nlm.nih.gov)

PSC can appear before, at the same time as, or many years after IBD is diagnosed. The activity of PSC in the liver does not reliably track with gut symptoms. Someone can have quiet UC and still have active PSC, or the other way around. (ncbi.nlm.nih.gov)

Because PSC is relatively rare, most people with UC will never develop it. At the same time, the stakes are high for those who do, which is why liver monitoring is built into long‑term IBD care.

Symptoms and How PSC Is Detected

Many people with early PSC feel completely well. The condition is often picked up when routine blood tests show a cholestatic pattern, especially:

• Raised alkaline phosphatase (ALP)

• Raised gamma‑glutamyl transferase (GGT)

• Sometimes mild increases in ALT and AST

• Later, increased bilirubin

This pattern, especially when it persists, usually prompts further liver work‑up and bile duct imaging. (en.wikipedia.org)

When symptoms do appear, they can include:

• Fatigue

• Itchy skin (pruritus)

• Yellowing of skin or eyes (jaundice)

• Dark urine and pale stools

• Right upper abdominal discomfort

• Fever and chills during episodes of bacterial cholangitis

As PSC advances, signs of cirrhosis can appear, such as fluid in the abdomen, enlarged spleen, or easy bruising.

Diagnosis is usually based on:

• Blood tests

• Magnetic resonance cholangiopancreatography (MRCP), which shows typical bile duct narrowing and dilatation

• Sometimes liver biopsy, especially if imaging is normal but suspicion remains for small‑duct PSC (journals.lww.com)

Liver Monitoring in People With IBD

For people with IBD without known PSC

In IBD, liver tests serve several roles:

• Detecting extraintestinal liver diseases like PSC

• Monitoring for medication‑related liver injury

• Watching for other liver conditions that can coexist with IBD

Care teams commonly order liver blood tests at diagnosis, before starting new systemic medicines, and at intervals during treatment. Tests usually include ALT, AST, ALP, GGT, and bilirubin.

Findings that raise concern for PSC include:

• Persistently high ALP (with or without raised GGT)

• Unexplained cholestatic pattern not clearly linked to medicines, alcohol, or other known liver diseases

• Combination of these tests with typical symptoms such as itching or jaundice

When this pattern appears, guidelines recommend evaluation with high‑quality MRCP and further liver work‑up, rather than relying on more invasive procedures like diagnostic ERCP. (journals.lww.com)

For people with confirmed PSC

Once PSC is diagnosed, regular follow‑up is essential, whether or not gut symptoms are active. Expert societies advise:

• Periodic clinical review and standard liver blood tests, generally every 6–12 months, with closer follow‑up in higher‑risk cases (reference.medscape.com)

• Noninvasive assessment of liver scarring over time, such as elastography or fibrosis blood scores (reference.medscape.com)

• Routine attention to bone health and fat‑soluble vitamins, because long‑term cholestasis can weaken bones

The main treatment focus is managing symptoms, treating episodes of cholangitis, monitoring for progression, and planning for transplant evaluation if advanced disease or complications develop.

Cancer Risks and Colonoscopy Needs in PSC‑IBD

PSC brings important cancer risks that shape monitoring plans:

• Cholangiocarcinoma (bile duct cancer) risk is much higher in PSC than in the general population.

• Gallbladder cancer and, in those with cirrhosis, hepatocellular carcinoma (liver cancer) are also more common. (pubmed.ncbi.nlm.nih.gov)

Because of this, societies such as AASLD and AGA recommend regular imaging of the liver and bile ducts, often MRI/MRCP or ultrasound every 6–12 months, sometimes with a tumor marker blood test called CA 19‑9. (guidelinecentral.com)

For the colon, the combination of PSC and IBD, especially UC, greatly raises the chance of colorectal dysplasia and cancer compared with IBD alone, with roughly a threefold higher risk in pooled studies. (pubmed.ncbi.nlm.nih.gov)

Key colonoscopy principles in PSC‑IBD include:

• Colonoscopic surveillance begins as soon as PSC is diagnosed, not 8 years after IBD onset as in standard IBD pathways. (academic.oup.com)

• High‑definition colonoscopy with targeted biopsies, often with dye‑spray chromoendoscopy when available, is preferred. (journals.lww.com)

• Surveillance is repeated every 1–2 years as long as both conditions are present, even after liver transplant. (reference.medscape.com)

These schedules may be adapted for individual risk factors, but the overall theme is clear: once PSC and IBD coexist, colon cancer prevention becomes a central part of long‑term care.

FAQs

Does treating UC well make PSC go away?

Current evidence suggests that controlling bowel inflammation does not reliably change the course of PSC. The two diseases can behave quite independently, so liver monitoring must continue even when UC is in deep remission. (ncbi.nlm.nih.gov)

How worried should someone with UC be about PSC?

PSC remains uncommon among people with UC, affecting only a small minority. However, because it is serious and often silent at first, routine liver blood tests and careful review of any abnormal results are important parts of UC follow‑up. (pubmed.ncbi.nlm.nih.gov)

Does colectomy cure PSC?

Removing the colon can cure UC but does not cure PSC. Many people continue to need liver and bile duct monitoring after colectomy, and PSC can still progress or recur after liver transplantation. (aasld.org)

When should liver tests be checked in IBD?

Liver tests are commonly checked at diagnosis, before and during systemic medicines, and any time symptoms or prior results raise concern. The exact schedule is individualized, but the goal is to catch problems like PSC or drug‑related injury early, when there is more time to act.