Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by inflammation and fibrosis of the intra‐ and extrahepatic bile ducts. Disease progression often results in biliary cirrhosis and hepatic failure. The only successful treatment has been liver transplantation. The etiopathogenesis remains poorly understood, which is why development of medical therapies has been extremely challenging.

The diagnosis of PSC is made by cholangiography (Figure 44.1). Both intrahepatic and extrahepatic ducts can be affected. Segmental bile duct fibrosis with subsequent saccular dilation with normal intervening areas results in the characteristic beaded pattern frequently noted on the cholangiogram. The use of magnetic resonance cholangiopancreatography for accurate detection of suspected PSC has been increasingly useful (Figure 44.2). Liver biopsy is rarely used in the management of PSC; histological findings include periductal fibrosis with inflammation, bile duct proliferation, and ductopenia (Figure 44.3). Fibroobliterative cholangiopathy (Figure 44.4) is considered the most diagnostic finding on liver biopsy but is present in only about 10% of biopsies obtained in PSC patients. Explant findings often reveal liver fibrotic reactions surrounding the large bile ducts (Figure 44.5).

The recognition of elevated serum hepatic biochemistries consistent with cholestasis in a patient with concurrent inflammatory bowel disease (IBD) is strongly suggestive of PSC; the absence of IBD does not exclude PSC. IBD, most commonly chronic ulcerative colitis, and PSC frequently coexist; the reported prevalence of IBD in patients with PSC is 70–80%, whereas the frequency of PSC in patients with IBD is only 2.1–7.5%. In those PSC patients who undergo proctocolectomy, the formation of peristomal varices with severe bleeding can be a major complication and a cause of significant morbidity (Figure 44.6). In such cases a surgical portocaval shunt or a transjugular intrahepatic portal shunt (TIPS) procedure has been effective. In addition, pouchitis following proctocolectomy seems to be more frequent and more severe in PSC patients than in those with ulcerative colitis alone (Figure 44.7).

The differential diagnosis of PSC includes biliary obstruction from choledocholithiasis, stricture, or malignancy, primary biliary cirrhosis, immunoglobulin G4‐related sclerosing cholangitis/autoimmune pancreatitis, recurrent pyogenic cholangitis, fungal cholangitis, acquired immunodeficiency syndrome cholangiopathy, choledochal cysts, cystic fibrosis, primary portal hypertension, intrahepatic hepatocellular carcinoma, and eosinophilic cholangitis.

Metabolic bone disease, most commonly osteoporosis, is seen in relation to PSC patients (Figure 44.8). Approximately 50% of patients have osteopenia, whereas osteoporosis develops in less than 10% of cases. Initial treatment with calcium and weight‐bearing activity is essential. Oral replacement therapy with vitamin D is indicated if measured serum levels are reduced. The use of bisphosphonates has been proven to be effective in preventing bone mineral loss.

Bacterial cholangitis is most commonly associated with a previous history of biliary tract surgery, bile duct calculi, or dominant stricture. Therapy includes empiric broad‐spectrum intravenous antibiotics and biliary decompression when clinically indicated. Dominant strictures occur in 45–62.5% of PSC patients (Figure 44.9). Clinical manifestations include progressive jaundice, symptoms of bacterial cholangitis, and dark urine. Diagnosis and therapy include endoscopic or radiological approaches to dilate the dominant stricture and often provide significant and clinical improvement.

The most serious complication of PSC is the development of cholangiocarcinoma (CCA), which can be divided into three types according to anatomical location: perihilar (50–60%), distal (20–30%), and intrahepatic (20%). Risk factors for CCA include advanced age, long duration of IBD, advanced hepatic disease, cigarette smoking, colorectal neoplasia, and carcinoma. Confirming the diagnosis of CCA in PSC is challenging. The distinction between benign and malignant biliary strictures with cross‐sectional imaging and cholangiography can be helpful in making the diagnosis (Figure 44.10). Serum tumor markers, particularly carbohydrate antigen 19‐9, have been useful in diagnosing CCA in patients with PSC. Rarely, bile duct dysplasia or carcinoma can be diagnosed on liver biopsy (Figure 44.11). At least one report has suggested that positron emission tomography (PET) scanning can be helpful in diagnosing CCA complicating PSC (Figure 44.12). The use of biliary cytology, digital image analysis, and fluorescence in situ hybridization (FISH) studies can also be helpful in diagnosing CCA in patients with PSC (Figures 44.13 and 44.14). Some studies also suggest that cholangioscopy can be helpful in distinguishing between malignant and benign dominant bile duct strictures in patients with PSC (Figure 44.15).

Recently, a new score, called PRESTO (Primary Sclerosing Cholangitis Risk Estimate Tool) has been developed and validated to improve a clinician’s ability to predict the prognosis of a patient with PSC. PRESTO uses the following clinical variables to calculate the score: serum total bilirubin, albumin, serum alkaline phosphatase, platelet count, aspartate aminotransferase, age, PSC duration, hemoglobin, and serum sodium level (Figure 44.16). The PRESTO score can be calculated online on the following website:

https://rtools.mayo.edu/PRESTO_calculator/?_ga=2.243955841.527710396.1583449885‐968311735.1583449885

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