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DictionarySeesyndromeEncyclopediaSeehyperbilirubinemiaDubin-Johnson syndrome
hyperbilirubinemia [hi″per-bil″ĭ-roo″bĭ-ne´me-ah] an excess of bilirubin" >bilirubin in the blood, occurring as a result of liver or biliary tract dysfunction or with excessive destruction of red blood cells. It is classified as conjugated or unconjugated, according to the type of bilirubin present. Jaundice is manifested when excess bilirubin is deposited in the skin and mucous membranes.hyperbilirubinemia I Gilbert disease.hyperbilirubinemia II a chronic idiopathic jaundice, transmitted as an autosomal recessive trait, that affects the excretory function of the liver. The resulting increase in serum conjugated bilirubin is caused by defective transport of conjugated bilirubin into the biliary tract. The condition is generally harmless. Called also Dubin-Johnson syndrome.conjugated hyperbilirubinemia, Type III a form of conjugated hyperbilirubinemia; probably the result of a primary defect in the storage or hepatic uptake of bilirubin.hyperbilirubinemia in the newborn excess serum bilirubin in the newborn due either to overproduction of bilirubin, as in excessive destruction of erythrocytes, or to reduction in glucuronide conjugation in the liver. If a high level of bilirubinemia is left untreated, kernicterus may occur as a result of free unconjugated bilirubin entering the brain tissue and causing neurotoxic damage. The exact level at which kernicterus will occur in individual newborns has not been established. There is evidence that bilirubin levels as low as 6 to 9 mg/dl in very-low-birth-weight and preterm infants puts them at risk for kernicterus and brain damage.Treatment. The goal of therapy is to reduce serum bilirubin and prevent kernicterus, which virtually disappears when bilirubin levels are controlled. Phototherapy is the standard treatment for nonhemolytic hyperbilirubinemia. It may be used prophylactically in newborns at high risk, for example, in preterm, low-birth-weight, and very-low-birth-weight newborns. transfusions" >Exchange transfusions are used for treatment of moderate to severe hemolytic disease, or when excessive bilirubinemia in preterm newborns is not controlled by phototherapy.Patient Care. Newborns most at risk for hyperbilirubinemia are those who are preterm, who display bruising, or who have blood incompatibilities, an enclosed hemorrhage such as cephalhematoma, polycythemia, an intrauterine infection, congenital red blood cell abnormality, or congenital hypothyroidism or galactosemia. Observation of the newborn for jaundice is of primary importance, especially those predisposed to hyperbilirubinemia. Yellowing of the skin is first apparent on the face, progressing downward as it increases in severity. The time at which jaundice is first noticed also is significant. Laboratory data can provide information on the levels of direct and indirect serum bilirubin, the hematocrit, variations in red cell morphology, reticulocyte count, Coombs' test and crossmatching of the infant's cells and maternal serum to detect abnormal antibodies when infant and mother are of the same blood type, and special tests for enzyme deficiencies and galactosemia. Clinical jaundice is investigated when the jaundice appears in the first 12 hours of life and serum bilirubin levels rise at the rate of more than 3 mg per hour. These signs are indicative of hemolytic jaundice, which may require an exchange transfusion. Physiologic jaundice, which is due to immature liver function, rarely becomes apparent before the third day of life or persists beyond the first week and does not exceed 12 mg in term infants. Other observations include noting any bruising, which causes hemolysis of erythrocytes and release of the bilirubin component, and assessment for cephalhematoma, which has the same effect as bruising because accumulated red blood cells are broken down. Intestinal obstruction also can lead to a buildup of serum bilirubin. The unevacuated stool contains bile which is broken down by intestinal flora into its basic components, thus allowing the release of bilirubin into the blood stream. Care of the newborn receiving phototherapy includes protection of the skin and eyes from ultraviolet radiation. Care of the newborn receiving an transfusion" >exchange transfusion is discussed under that topic.Du·bin-John·son syn·drome (dū'bin jon'sŏn), [MIM*237500] an inherited defect in hepatic excretory function characterized by jaundice with levels of serum bilirubin up to about 6 mg/dL, over half of which is conjugated, and excretion of abnormal proportions of coproporphyrin I in urine. There is also retention of a dark pigment in the hepatocytes that is derived either from melanin or catecholamines, but otherwise liver histology examination provides normal results. Oral cholecystogram fails to visualize the gallbladder; excretion of test substances (for example, bromosulfothalein) by the liver is abnormal. The basic defect is apparently in canalicular transport. No therapy is necessary; autosomal recessive inheritance caused by mutation in the canalicular multispecific organic anion transporter gene (CMOAT) on 10q. Synonym(s): chronic idiopathic jaundiceA popular term for a rare autosomal recessive [MIM 237500] condition which is asymptomatic, and characterised by a blackened liver caused by defective conjugated bilirubin excretion; bilirubin levels are usually 120 µmol/L—US 7 mg/dl—60% conjugated—direct; estrogens should be avoided as they may intensify the jaundiceDu·bin-John·son syn·drome (dū'bin jon'sŏn sin'drōm) Inherited defect in hepatic excretory function characterized by jaundice with levels of serum bilirubin up to about 6 mg/dL, over half of which is conjugated, and excretion of abnormal proportions of coproporphyrin I in urine. There is also retention of a dark pigment in the hepatocytes that is derived either from melanin or catecholamines, but otherwise liver histology examination provides normal results. Dubin-Johnson syndrome A rare AUTOSOMAL RECESSIVE condition featuring a failure of BILIRUBIN transport in the liver and increased levels of bilirubin in the blood. There is sickness and mild JAUNDICE but the outlook is excellent. (Isadore Nathan Dubin, Canadian pathologist, b. 1913, and Frank Bacchus Johnson, American pathologist, b. 1919).Dubin, I. Nathan, U.S. pathologist, 1913-1980. Dubin-Johnson syndrome - chronic idiopathic jaundice. Synonym(s): Sprinz-Dubin syndrome; Sprinz-Nelson syndromeSprinz-Dubin syndrome - Synonym(s): Dubin-Johnson syndrome
Johnson, Frank B., U.S. pathologist, 1919–. Dubin-Johnson syndrome - Synonym(s): chronic idiopathic jaundice
Nelson, R.S., 20th century U.S. physician. Sprinz-Nelson syndrome - Synonym(s): Dubin-Johnson syndrome
Sprinz, Helmuth, German-born U.S. pathologist, 1911–. Sprinz-Dubin syndrome - Synonym(s): Dubin-Johnson syndromeSprinz-Nelson syndrome - Synonym(s): Dubin-Johnson syndromeAcronymsSeeDJS |