ABP Transplant Hepatology key terms

A progressive fibro-obstructive disease of infancy in which extrahepatic bile ducts are obliterated, causing cholestasis and cirrhosis if untreated. It is the most common indication for pediatric liver transplantation.

A hepatoportoenterostomy operation that removes the obliterated extrahepatic biliary remnant and connects a Roux limb to the liver hilum. Success is greatest when performed before about 60 days of age.

Conjugated hyperbilirubinemia beginning in the first months of life, defined by a direct or conjugated bilirubin above roughly 1 mg/dL when total bilirubin is elevated. It requires prompt evaluation for biliary atresia and metabolic disease.

An autosomal dominant multisystem disorder caused by JAG1 or NOTCH2 mutations, with bile duct paucity, cholestasis, butterfly vertebrae, peripheral pulmonary stenosis, characteristic facies, and posterior embryotoxon.

A group of inherited disorders of bile formation caused by mutations in bile transporter or canalicular proteins. They cause progressive cholestasis, pruritus, growth failure, and cirrhosis, often requiring biliary diversion or transplantation.

An autosomal codominant disorder caused by mutations in SERPINA1 that impair alpha-1 antitrypsin folding and secretion. Accumulated protein injures hepatocytes, while lung disease results from deficient antiprotease protection.

An autosomal recessive disorder of copper metabolism caused by ATP7B mutations. Copper accumulates in the liver, brain, cornea, and other tissues, producing hepatitis, cirrhosis, neuropsychiatric symptoms, and Kayser-Fleischer rings.

An autosomal recessive defect of fumarylacetoacetate hydrolase in tyrosine degradation. Toxic metabolites cause severe liver disease, renal tubular dysfunction, and risk of hepatocellular carcinoma; nitisinone plus dietary restriction is treatment.

A chronic immune-mediated liver injury characterized by hypergammaglobulinemia, autoantibodies, interface hepatitis on biopsy, and response to corticosteroids with or without azathioprine. It can present acutely or as advanced fibrosis in children.

Rapidly developing severe hepatocellular injury with coagulopathy and often hepatic encephalopathy in a child without preexisting chronic liver disease. It requires urgent transplant center referral and intensive supportive care.

Advanced liver fibrosis with regenerative nodules and distorted architecture, causing portal hypertension and impaired synthetic function. In children, causes include biliary atresia, metabolic disorders, and chronic hepatitis.

Elevated pressure in the portal venous system, usually from increased resistance to portal flow and augmented splanchnic inflow. It produces varices, splenomegaly, ascites, and portosystemic shunting in children with chronic liver disease.

Dilated submucosal veins in the esophagus that develop as collateral channels when portal pressure rises. They can rupture and cause life-threatening hematemesis or melena, especially in children with cirrhosis or portal vein thrombosis.

A reversible neuropsychiatric syndrome caused by liver dysfunction and portosystemic shunting, ranging from subtle attention deficits to coma. Diagnosis in children is clinical and requires excluding metabolic, infectious, and drug-related causes.

Abnormal accumulation of fluid in the peritoneal cavity due to portal hypertension, sodium retention, and low oncotic pressure. In children it may cause abdominal distention, respiratory compromise, and spontaneous bacterial peritonitis.

Bacterial infection of ascitic fluid without an obvious intra-abdominal surgical source, most often caused by enteric organisms. It requires diagnostic paracentesis and prompt antibiotics, often with albumin in high-risk patients.

Functional acute kidney injury in advanced liver disease caused by splanchnic vasodilation and renal vasoconstriction, without structural kidney damage. It is diagnosed after excluding other causes and often requires vasoconstrictors plus albumin.

A pulmonary vascular complication of liver disease characterized by intrapulmonary shunting, impaired oxygenation, and platypnea-orthodeoxia. Contrast echocardiography helps confirm shunting, and liver transplantation may reverse the condition.

Pulmonary arterial hypertension associated with portal hypertension, caused by pulmonary vascular remodeling. It is suspected when dyspnea or elevated right heart pressures occur and requires right heart catheterization for diagnosis and transplant risk assessment.

A percutaneous shunt placed between a hepatic vein and portal vein branch to decompress the portal system. In children it treats refractory variceal bleeding or ascites but risks encephalopathy, shunt dysfunction, and liver decompensation.

A pediatric waitlist priority score using age under one year, albumin, bilirubin, INR, growth failure, and sodium. Higher scores predict three-month waitlist mortality and guide organ allocation for children under twelve.

A prognostic score using bilirubin, creatinine, INR, and sodium that estimates three-month mortality in older children and adults with chronic liver disease. It is used for waitlist prioritization and may include pediatric exception points.

Urgent pediatric liver transplant categories for acute liver failure, primary graft nonfunction, hepatic artery thrombosis, or other catastrophic complications. Status 1A carries the highest priority and requires rapid evaluation and listing.

Additional priority points granted when a child's measured laboratory score underestimates mortality risk or disease severity. Examples include metabolic disease, growth failure, hepatopulmonary syndrome, and certain complications of cirrhosis.

Transplantation using a portion of liver from a healthy living donor, usually a parent. It reduces waiting time and cold ischemia but requires rigorous donor evaluation and carries donor surgical risk.

Division of a deceased donor liver into two grafts, typically a left lateral segment for a child and a larger portion for an adult. It expands the pediatric donor pool but increases technical complexity.

T-cell-mediated immune injury to the allograft, often presenting with fever, elevated liver enzymes, and biopsy findings of portal inflammation, bile duct damage, and endothelialitis. Treatment usually begins with high-dose corticosteroids.

Allograft injury caused by donor-specific antibodies binding graft endothelium, with complement activation and microvascular inflammation. Diagnosis uses serum antibody testing and biopsy, and treatment includes plasma exchange, intravenous immunoglobulin, and antibody reduction.

Drugs such as tacrolimus and cyclosporine that block T-cell activation by inhibiting calcineurin and interleukin-2 production. They prevent rejection but cause nephrotoxicity, hypertension, neurotoxicity, and metabolic complications.

A calcineurin inhibitor and cornerstone of pediatric liver transplant immunosuppression. It has narrow therapeutic indices, requires therapeutic drug monitoring, and can cause tremor, nephrotoxicity, hyperkalemia, and post-transplant diabetes.

An antimetabolite that inhibits lymphocyte proliferation by blocking inosine monophosphate dehydrogenase. It is used with calcineurin inhibitors to reduce rejection or allow dose reduction, but causes gastrointestinal upset and bone marrow suppression.

Sirolimus and everolimus are immunosuppressants that inhibit mammalian target of rapamycin, reducing T-cell proliferation. They may permit calcineurin inhibitor sparing but can cause dyslipidemia, proteinuria, poor wound healing, and mouth ulcers.

Intraoperative or early postoperative antibody therapy, such as basiliximab or antithymocyte globulin, that depletes or blocks T-cell activation. It reduces early rejection and allows delayed calcineurin inhibitor initiation in children with kidney dysfunction.

A spectrum of lymphoid proliferations after transplantation, often driven by Epstein-Barr virus and immunosuppression. It may present with lymphadenopathy, fever, or organ dysfunction; treatment includes immunosuppression reduction, rituximab, and chemotherapy.

Preventive antiviral therapy, commonly valganciclovir, given after transplant to children at risk for cytomegalovirus disease. Monitoring viral load and adjusting immunosuppression are important because cytomegalovirus causes hepatitis, colitis, and myelosuppression.

Occlusion of the hepatic artery after transplantation, causing biliary ischemia, graft dysfunction, and potentially graft loss. Early recognition with Doppler ultrasound is critical; treatment may require thrombectomy, revision, or retransplantation.

Narrowing at the surgical bile duct connection after liver transplantation, causing cholestasis, cholangitis, and graft dysfunction. It is managed with endoscopic or percutaneous dilation and stenting, sometimes requiring surgical revision.

Antibodies directed against donor human leukocyte antigens that may develop before or after transplantation. They are associated with antibody-mediated rejection, graft injury, and reduced long-term survival, prompting screening and tailored immunosuppression.

A clinical state in which a transplant recipient maintains stable graft function without immunosuppressive drugs. It is uncommon in children and requires careful protocolized withdrawal and close monitoring for rejection.

A herpesvirus that commonly infects children and persists latently. After transplantation, primary infection or reactivation under immunosuppression can cause post-transplant lymphoproliferative disorder, hepatitis, and fever.