PSC and PBC

The differences between PSC and PBC

PSC Support logo with PSCPlogoIt is important for the whole PSC community to be aware of the differences and similarities between the two diseases and to that end, with advice from leading clinical experts, PSC Support and PSC Partners Seeking a Cure have published a concise comparison of PSC (primary sclerosing cholangitis) and PBC (primary biliary cholangitis).

 

Please feel free to download and share our infographic:

 

Primary sclerosing cholangitis (PSC) is part of the family of ‘cholestatic liver diseases' [1]. This means it is a disease that affects the bile ducts – tubes that deliver bile from the liver to the small intestine. PSC occurs because of inflammation in the bile ducts (cholangitis), which results in hardening (sclerosis) and narrowing of the ducts [2]. As a result, bile cannot be released properly and it builds up in the liver where prolonged exposure results in liver damage.

 

The medical abbreviation for primary sclerosing cholangitis is PSC. Although medical abbreviations are designed to simplify disease names, they can sometimes cause confusion; particularly as other liver conditions incorporate similar names. Another closely related condition that you may have heard of is PBC (traditionally called primary biliary cirrhosis). Despite sharing common symptoms (such as itching and fatigue) and having comparable acronyms, PSC and PBC are distinct entities and exhibit important differences, including the site of tissue damage within the liver, associations with inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn’s disease response to treatment, and risks of disease progression [3]

 

In PSC, a key feature is the development of scar tissue (fibrosis) that predominantly affects the medium- to large-sized bile ducts within and outside the liver. This can most often be identified with a special MRI scan (called MRCP), although occasionally a liver biopsy is needed for confirmation. PSC can affect men and women at any age, although it is commonly diagnosed in the fourth decade of life, most often in the presence of inflammatory bowel disease (IBD) [2]

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Close monitoring of PSC patients is vital. Because of the increased colon cancer risk in PSC patients with ulcerative colitis, annual colonoscopies are advised.  Moreover, the presence of colitis is associated with a greater risk of liver disease progression and bile duct cancer (cholangiocarcinoma) [4]. Individuals with PSC can occasionally develop abdominal pain and fever, which may suggest infection of the bile ducts called cholangitis. Although the latter can be treated with antibiotics, no currently known treatment has been shown to slow the progression or cure PSC. There are, however, several clinical trials underway that aim to slow progression of liver disease [5].
 

By contrast, PBC mainly affects the small bile ducts in the liver itself and is not associated with biliary sclerosis [6]. In the current era, PBC can be identified through special antibody tests (performed on blood sampling) and liver biopsy is rarely needed. Over 90% of individuals with PBC are women, and the condition is most often diagnosed in middle age via a series of blood tests (see Table 1). Approximately two-thirds of patients with PBC can improve their liver blood tests whilst taking ursodeoxycholic acid (UDCA), and it is well recognized that this correlates with improved survival and a lower risk of liver transplantation [3]. Unlike primary sclerosing cholangitis, PBC does not share an association with IBD, colonic cancer or bile duct cancer; however individuals with PBC can occasionally develop thyroid problems, dry eyes (a condition called ‘Sicca syndrome/Sjogren’s syndrome) or intolerance to gluten in wheat (coeliac disease) [7].

 

It is important to recognise that PBC and PSC are different diseases; stemming from the way they are diagnosed, the association with IBD, and the way they are monitored and respond to treatment. The layers of complexity in PSC require the care of clinicians experienced in treating PSC and knowledgeable in current PSC research.

 
Table 1. Similarities and Differences Between PSC and PBC 

Feature

PSC - primary sclerosing cholangitis

PBC - primary biliary cholangitis

Site of disease involvement

Bile ducts inside and outside the liver; however in small duct PSC (10-15% of patients) only the small ducts inside the liver are affected

Small bile ducts inside the liver only

Mode of diagnosis

Usually by MRI of bile ducts. Occasionally liver biopsy or ERCP is needed

Two of the following: Raised ALP, positive disease specific antibodies (AMA), diagnostic liver biopsy

Associated with increased risk of bile duct and colon cancer

Yes

No

Response to Ursodeoxycholic acid (UDCA)

Improves liver blood tests in some patients; not conclusively proven to slow disease progression

Associated with improved prognosis in those individuals who respond well to UDCA

Co-existing inflammatory bowel disease (IBD)

Around 80% of patients have IBD - mostly colitis

Very rare and not characteristic; around 1%

Common symptoms in early disease

Itching, fatigue, abdominal pain, cholangitis flares

Itching, fatigue, dry eyes and mouth, abdominal pain

Gender predominance

60% men, 40% women

90% women, 10% men

Average age at diagnosis

Any age; mostly around 40 years

75% are affected in middle age (>45 years old)

Associated with excess alcohol consumption?

No

No

Associated with smoking

Most often non-smokers

Associated with a history of smoking [8,9]

 

 

13 November 2015 (prepared by PSC Support, PSC Partners Seeking a Cure, Dr Gideon Hirschfield and Dr Palak Trivedi)

(Table 1 updated 8 November 2016, Infographic added 07 September 2017)

 


Background

The international community of the bile duct disease PBC (primary biliary cirrhosis) has changed the name of its disease to 'primary biliary cholangitis'.

PSC Partners Seeking a Cure in the US and PSC Support are using this name change as an opportunity to spread awareness of PSC, to help PSC patients take charge of their disease, and to focus on meeting the specific and wide-ranging needs of PSC patients.

 

Why you need to understand the difference between PSC and PBC

PSC and PBC sound like the same disease. Focusing solely on the names of these conditions, both are 'primary' diseases (not secondary, that is, not caused by another condition). Both are 'biliary', that is, diseases of the bile ducts. Following the name change for PBC, both are now characterised by the term 'cholangitis'.  However, the two diseases are not the same, despite sharing certain similar characteristics and symptoms. Each condition creates different needs among patients, and each requires different treatments and monitoring. 

We have witnessed errors caused by the similarities in the name of the two diseases. We encourage you to be informed about the differences between the two diseases, and to ensure that your care providers are similarly informed. Our two organisations (PSC Partners Seeking a Cure in the US and PSC Support in the United Kingdom) have worked together with hepatologists who see the importance of educating our patients on this issue. 

"It is critical that you are correctly diagnosed with PSC in a timely manner. PSC is very different to PBC. Because PSC carries an increased risk of cancers including bile duct cancer (cholangiocarcinoma) and colon cancer, patients with PSC must be monitored from diagnosis," states Martine Walmsley, Chair of Trustees of PSC Support. "Unlike PBC, PSC has no effective treatment and so every PSC patient should be offered the chance to take part in research such as the UK-PSC Study to help find that cure, or be considered for inclusion in clinical trials of potential new drugs."

 

Why the name change?

Patients with PBC have justifiably wanted to change the name of their disease to avoid the stigma of the term 'cirrhosis'.  They changed the term cirrhosis to cholangitis to prevent the misconception that their disease is caused by alcohol overuse.  The second reason for their name change was that 80% of patients with PBC no longer progress to cirrhosis. Unlike most patients with PSC, a large number of PBC patients respond to ursodeoxycholic acid (UDCA), which in their case slows down disease progression. The term cirrhosis in their name no longer reflects the reality of their disease. 

 

 


 

Acknowledgements

PSC Support and PSC Partners Seeking a Cure would like to thank Professor Gideon Hirschfield and Dr Palak Trivedi for their involvement in helping us provide a concise comparison between PSC and PBC.

Professor Gideon Hirschfield: Professor/Consultant Hepatologist; University of Birmingham (UK)/University Hospitals Birmingham; Chief Investigator for UKPSC

Dr Palak Trivedi: Academic Clinical Lecturer and SPR in Hepatology and Gastroenterology, NIHR Centre for Liver Research; University of Birmingham (UK).

 

References

1          EASL Clinical Practice Guidelines: management of cholestatic liver diseases. J Hepatol 2009;51:237–67. doi:10.1016/j.jhep.2009.04.009

2          Hirschfield GM, Karlsen TH, Lindor KD, et al. Primary sclerosing cholangitis. Lancet 2013;382:1587–99. doi:10.1016/S0140-6736(13)60096-3

3          Trivedi PJ, Corpechot C, Pares A, et al. Risk Stratification in autoimmune cholestatic liver diseases: Opportunities for clinicians and trialists. Hepatology 2015;:n/a – n/a. doi:10.1002/hep.28128

4          Boonstra K, Weersma RK, van Erpecum KJ, et al. Population-based epidemiology, malignancy risk, and outcome of primary sclerosing cholangitis. Hepatology 2013;58:2045–55. doi:10.1002/hep.26565

5          Trivedi PJ, Hirschfield GM. Treatment of autoimmune liver disease: current and future therapeutic options. Ther Adv Chronic Dis 2013;4:119–41. doi:10.1177/2040622313478646

6          Hirschfield GM, Gershwin ME. The immunobiology and pathophysiology of primary biliary cirrhosis. Annu Rev Pathol 2013;8:303–30. doi:10.1146/annurev-pathol-020712-164014

7          Floreani A, Franceschet I, Cazzagon N, et al. Extrahepatic autoimmune conditions associated with primary biliary cirrhosis. Clin Rev Allergy Immunol 2015;48:192–7. doi:10.1007/s12016-014-8427-x

8          Corpechot C, Gaouar F, Chrétien Y, et al. Smoking as an independent risk factor of liver fibrosis in primary biliary cirrhosis. J Hepatol. 2012 Jan;56(1):218-24. doi: 10.1016/j.jhep.2011.03.031. Epub 2011 May 19.

         Juran BD, Lazaridis KN. Environmental factors in primary biliary cirrhosis. Semin Liver Dis. 2014 Aug;34(3):265-72. doi: 10.1055/s-0034-1383726. Epub 2014 Jul 24.

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