Primary Sclerosing Cholangitis 2016

Though this blog has reviewed primary sclerosing cholangitis (PSC), it has been a while since I’ve posted much.  As such, I thought I would place a post of a recent review (KN Lazaridis, NF LaRusso. NEJM 2016; 375; 1161-70).

Key points:

Epidemiology:

  • Strongly associated with inflammatory bowel disease with 70-80% of PSC patients having IBD
  • Median age at diagnosis 41 years with ~6-% male

Clinical manifestations:

  • Insidious disease in most.  “About half the patients with this condition do not have symptoms but receive a diagnosis after liver-function tests are found to be abnormal.”
  • Diagnostic criteria include increased alkaline phosphatase for more than 6 months
  • In adults, a liver biopsy is not need for diagnosis
  • Tends to be slowly progressive
  • Bacterial cholangitis is reported as initial presentation in ~6% and can be recurrent and intractable
  • Colon cancer is more frequent in patients with PSC.  “Colonoscopy is warranted in all patients who have received a new diagnosis”

Subtypes:

  • Classic subtype (90%) involves the entire biliary tree
  • ~5% have only small intrahepatic bile duct involvement
  • ~5% of adults have overlap syndrome with autoimmune hepatitis.  In children, overlap syndrome is present in ~35%.
  • There are numerous “secondary” PSC causes including AIDS-related cholangiopathy, amyloidoiss, eosinophilic cholangiopathy, histiocytosis X, IgG4-associated cholangitis, and sarcoidosis (most extensive list -see Table 1)

Pathogenesis:

  • The exact reasons remain unclear.  There are associations with environmental triggers but these have not been proven to be causally related.  For example, patients with PSC are more likely to consume steak or hamburger compared with controls and less likely to consume similar amounts of fish.
  • Due to its association with IBD, there are “microbiota hypothesis” to account for the aberrant cholangiocytic response.

psc-nejm

Treatment:

  • “As of this writing, no effective medical therapy exists.”
  • The authors detail eight potential treatments that are being studied: obeticholic acid, simtuzumab, 24-nor-ursodeoxycholic acid, an apical sodium-dependent bile acid transporter inhibitor (LUM001), a human monoclonal antibody that targets vascular adhesion protein 1 (BTT1023), oral vancomycin (NCT01802073 -pediatric trial), and fecal microbiota transplantation.
  • Management: includes managing varices in those with cirrhosis, following for benign and malignant biliary strictures, following for gallbladder disease (eg. polyps or masses), colon cancer surveillance (typically yearly screening), and managing metabolic bone disease.

Briefly noted: M Bramuzzo et al. JPGN 2016; 63: 259-64.  Using an Italian Pediatric IBD registry, the authors noted 6.8% of 677 patients had autoimmune liver disease: 61% with PSC and 33% with overlap syndrome.

Related blog posts:

 

 

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