Posthepatic

Posthepatic refers to conditions in which bile flow is obstructed after it leaves the liver, typically within the biliary tree, gallbladder, or the extrahepatic ducts. In medicine, posthepatic jaundice is the form of obstructive jaundice arising from such blockages, leading to impaired excretion of conjugated bilirubin into the intestine.

Pathophysiology and presentation arise from obstruction of bile flow. Conjugated bilirubin accumulates in the blood, causing yellowing of the skin and eyes. Urine may be dark from bilirubinuria, and stools often pale due to a lack of stercobilin. Bile acids accumulate in the skin, contributing to pruritus. Laboratory findings typically show elevated direct (conjugated) bilirubin, increased alkaline phosphatase and gamma-glutamyl transferase, and milder transaminase elevations compared with prehepatic causes.

Common causes include choledocholithiasis (stones in the common bile duct), benign or malignant biliary strictures, pancreatic head or other malignancies compressing the bile ducts, sphincter of Oddi dysfunction, and congenital biliary atresia or biliary anomalies in some populations. Less frequent causes include post-surgical bile duct injury and inflammatory strictures such as primary sclerosing cholangitis in certain contexts.

Diagnosis combines laboratory testing with imaging. Noninvasive imaging such as abdominal ultrasound is often the first step, followed by MRCP (magnetic resonance cholangiopancreatography) to delineate the biliary tree. Endoscopic retrograde cholangiopancreatography (ERCP) is used both diagnostically and therapeutically to remove stones, dilate strictures, or place stents; CT or endoscopic ultrasound may aid in identifying masses. Management focuses on relieving the obstruction and addressing the underlying cause, with antibiotics for cholangitis and surgical or endoscopic interventions as appropriate. Prognosis depends on the cause and success of biliary decompression.