Krigler-Najjar syndrome
Introduction
Introduction to Kriegler-Najar Syndrome Crigler-najjarsyndrome (CNS), also known as congenital glucuronyltransferase deficiency, congenital non-obstructive non-hemolytic jaundice, is a rare occurrence in newborns Hereditary hyperbilirubinemia in infants and young children. basic knowledge The proportion of illness: 0.001% Susceptible people: good for newborns and infants Mode of infection: non-infectious Complications: coma
Cause
Cause of Kriegler-Najar syndrome
(1) Causes of the disease
Kriegler-Najar syndrome type I, first reported by Crigler in 1952, is autosomal recessive, parents are mostly close relatives, and the glucuronyltransferase in the liver cells of the child is completely lacking and cannot form a combination. Bilirubin, the blood-induced unconjugated bilirubin is significantly increased, too high fat-soluble unconjugated bilirubin, through the undeveloped blood-cerebrospinal fluid barrier, diffuses into the cerebrospinal fluid and brain parenchyma, causing bilirubin encephalopathy.
The Kriegler-Najar syndrome type II, discovered by Arias in 1962, is also known as Arias Syndrome. It is generally considered to be autosomal dominant, with incomplete explicit appearance, and parents rarely have close relatives. In children, hepatic cells are partially deficient in glucuronyltransferase, causing bilirubin binding disorder, causing unbound bilirubin to increase, because a small amount of bound bilirubin can still be produced, so bilirubin encephalopathy is less likely to occur.
(two) pathogenesis
Due to gene mutations in different regions of the coding region of uracil diphosphate glucuronyltransferase (UGT1A1), UGT1Al enzyme activity is reduced or even absent; Krigler-Najar syndrome is classified into type I according to the degree of deficiency of UGT1A1. Type II, type I is an autosomal recessive genotype, UGT1 disappears completely in the liver; type II, autosomal dominant inheritance, glucuronyltransferase activity is reduced but does not disappear, due to the reduction or even lack of UGT1A1 enzyme activity, thus Causes bilirubin to bind to dysfunction.
There was no special change in the histopathology of the liver of the patient. Only the bile duct was found in the capillary bile duct. In patients with nuclear jaundice, the basal ganglia of the brain was deeply stained by unconjugated bilirubin.
Prevention
Kriegler-Najar syndrome prevention
There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.
Complication
Kyle-Najar syndrome complications Complications
Type I can cause drowsiness, convulsions, angulation, muscle spasm and rigidity, coma, type II can have mental abnormalities, sensory defects, and tension tremors.
Symptom
Kyle-Najar syndrome symptoms common symptoms jaundice angulation
Type I is rare. It was first reported by Crigler-Najjar in 1952. The patient is homozygous for the crigle-najjar-type gene. The neonates develop jaundice rapidly after birth. Most of them have significant jaundice and bilirubin 1 to 4 days after birth. The concentration can be as high as 289-816 mol/L, 90% is unconjugated bilirubin; due to the affinity of unconjugated bilirubin for brain tissue, muscle spasm and rigidity, convulsions, angulation, etc. often occur within 2 weeks after birth. Bilirubin encephalopathy, the patient has no hemolysis, bile is colorless, no bilirubin, normal gallbladder angiography.
Type II is rare, but more common than type I. It was found in 1962 to be a heterozygous gene of Grigrer-Najjar type. The patient developed jaundice shortly after birth, and also developed in childhood or adulthood. The condition is relatively lighter than type I. Neurological symptoms, mental development is normal, jaundice is slightly lower than type I, serum bilirubin fluctuates from 85 to 374 mol/L, bilirubin encephalopathy is rare, bile is pigmented, and there is a considerable amount of urobilin in feces, only A small number of patients have high levels of unconjugated bilirubin in the blood, which causes damage to the extrapyramidal system, and other liver function tests are normal.
Examine
Examination of the Kriegler-Najar syndrome
Serious jaundice, serum bilirubin>340mol/L, accompanied by bilirubin encephalopathy, phenobarbital treatment is invalid, diagnosed as type I; jaundice is mild, serum bilirubin <340mol/L, neurological symptoms Not obvious, phenobarbital treatment has a certain effect, diagnosed as this type II.
Liver biopsy under normal light microscope, occasional gallbladder embolism, the structure of liver cells is almost normal under electron microscope, type I can be seen that the endoplasmic reticulum of hepatocytes is more prominent, irregular vesicles are occasionally seen in hepatocytes, and special particles exist in cytoplasm, II Type may have hepatic smooth surface endoplasmic reticulum hypertrophy and hyperplasia, accompanied by bilirubin encephalopathy, visible cerebral cortex, thalamus and basal ganglia are deeply stained with bilirubin, kidney papilla, intestinal mucosa, endocardium, etc. There is significant bilirubin deposition.
Diagnosis
Diagnosis and identification of Kriegler-Najar syndrome
Type I diagnosis is mainly based on serum unconjugated bilirubin, and there is no evidence of hemolysis, liver function and liver biopsy are normal, type II: due to partial deficiency of intrahepatic BGT, treatment with phenobarbital can reduce serum gallbladder The concentration of erythropoietin can be clinically determined by its therapeutic response to an enzyme-inducing agent to identify type I or type II Kriegler-Najar syndrome.
Need to identify the neonatal hemolytic jaundice caused by infection, neonatal ABO hemolytic disease, Rh hemolytic disease.
