Key Pathophysiological and Clinical Features of Primary Sclerosing Cholangitis

Disease Definition and Mechanism

• PSC is a chronic immune‑mediated cholestatic liver disease characterized by progressive inflammation and fibrosis of intra‑ and extra‑hepatic bile ducts, resulting in multifocal strictures, biliary cirrhosis, and eventual hepatic decompensation. 1
• The inflammatory process induces periductular fibrosis that creates the typical multifocal strictures and segmental ductal dilatations seen on imaging. 1

Biochemical Manifestations

• Cholestasis in PSC produces a biochemical profile of parallel elevation of alkaline phosphatase and γ‑glutamyl transpeptidase. 2, 3
• Advanced cholestasis leads to malabsorption of fat‑soluble vitamins and predisposes to osteopenic bone disease. 2
• Elevated serum bilirubin signals more advanced disease and is associated with poorer prognosis. 3, 4
• Aminotransferase levels are usually 2–3 times the upper limit of normal, indicating hepatocellular injury secondary to cholestasis. 2

Immunologic Markers

• Perinuclear antineutrophil cytoplasmic antibodies are present in 33‑88 % of PSC patients but do not correlate with disease activity. 3, 4

Associated Conditions

• Up to 80 % of individuals with PSC have concurrent inflammatory bowel disease, most often ulcerative colitis. 1, 2
• PSC‑associated colitis frequently presents as extensive pancolitis (≈87 % of cases) and shows higher rates of backwash ileitis and rectal sparing compared with ulcerative colitis alone. 5

Microbiological Factors

• Bacterial colonization of the bile ducts can occur at sites of dominant strictures, precipitating secondary cholangitis and potentially accelerating disease progression. 6

Disease Progression and Complications

• The natural history of PSC is progressive, with most patients developing cirrhosis, portal hypertension, and hepatic decompensation over time. 1
• Dominant strictures may cause acute cholestasis, bacterial cholangitis, and faster progression of liver disease. 6
• Progressive fibrosis culminates in biliary cirrhosis accompanied by portal hypertension, ascites, and risk of variceal hemorrhage. 2
• Patients with PSC have a markedly increased lifetime risk of cholangiocarcinoma and colorectal adenocarcinoma. 7

Clinical Presentation

• Approximately half of PSC patients are asymptomatic at diagnosis, with disease identified incidentally. 2
• When symptomatic, typical manifestations include pruritus, right‑upper‑quadrant discomfort, fatigue, and weight loss, reflecting cholestatic injury. 1, 2
• Fever and chills from bacterial cholangitis are uncommon at initial presentation unless the patient has undergone prior biliary instrumentation. 1

Cholangite Sclérosante Primitive et Autres Formes de Cholangite

Caractéristiques et Classification

• La cholangite sclérosante primitive (CSP) est une maladie hépatique cholestatique chronique caractérisée par l'inflammation et la fibrose des voies biliaires intrahépatiques et/ou extrahépatiques, entraînant une cholestase, des sténoses des voies biliaires et une fibrose hépatique pouvant évoluer vers une cirrhose et une décompensation hépatique, fortement associée aux maladies inflammatoires de l'intestin, avec une incidence estimée entre 0,91 et 1,3 pour 100 000 personnes-années 8
• La CSP peut être diagnostiquée à l'aide d'une cholangiographie par résonance magnétique (CPRM) ou d'une cholangiographie directe (CPRE), et les patients présentent souvent des symptômes tels que des douleurs dans le quadrant supérieur droit, un prurit, une fatigue et un ictère 8

Diagnostic et Examens

• Le profil biochimique cholestatique avec élévation de la phosphatase alcaline et de la bilirubine est caractéristique de la CSP, et la mesure des taux sériques d'IgG4 est recommandée pour exclure une cholangite associée aux IgG4 9
• La CPRM ou la CPRE sont recommandées pour le diagnostic de la CSP chez les patients présentant un profil biochimique cholestatique, et la biopsie hépatique est recommandée pour diagnostiquer la CSP à petits canaux chez les patients avec une CPRE ou une CPRM normales 9

Traitement et Pronostic

• La transplantation hépatique est le seul traitement définitif pour la CSP, mais les thérapies médicales (acide ursodésoxycholique) et les interventions endoscopiques peuvent améliorer la qualité de vie, et la dilatation endoscopique ou percutanée des sténoses biliaires et le drainage peuvent être nécessaires 10
• La cholangite associée aux IgG4 répond favorablement aux médicaments immunosuppresseurs, notamment aux corticostéroïdes 9

Key Pathophysiological and Clinical Facts of Primary Sclerosing Cholangitis

Disease Definition

• Primary sclerosing cholangitis (PSC) is an immune‑mediated chronic liver disease that causes progressive inflammation, fibrosis, and destruction of intra‑ and/or extra‑hepatic bile ducts, leading to cholestasis, multifocal strictures, hepatic fibrosis, cirrhosis, portal hypertension, and hepatic decompensation. 11

Immune‑Mediated Mechanisms

• The central pathogenic process is immune‑mediated injury of biliary epithelial cells, supported by genetic risk loci, chronic portal‑tract inflammation, and a strong association with inflammatory bowel disease, indicating an immune‑driven attack on the bile‑duct epithelium. 12
• Additional immunogenetic evidence reinforces the role of both genetic predisposition and immune dysregulation in PSC pathogenesis. 13

Histopathology

• Periductal concentric (“onion‑skin”) fibrosis is the classic histologic hallmark of PSC, although it is infrequently captured in routine liver biopsies. 14

Disease Complications

Dominant Biliary Strictures

• Dominant strictures—defined as a bile‑duct lumen ≤1.5 mm in the common bile duct or ≤1 mm in the hepatic duct—develop in 45 %–58 % of PSC patients during follow‑up and are associated with acute cholestasis, bacterial cholangitis, and accelerated liver‑disease progression. 14

Malignancy Risk

• Approximately 10 %–15 % of individuals with PSC develop cholangiocarcinoma, most often presenting as a perihilar stenotic lesion. 14

Prognostic Biomarkers

• Rising serum bilirubin levels reflect more advanced disease stage and correlate with a markedly poorer prognosis in PSC. 12