Hyperbilirubinemia plasma bilirubin

Depending on the type of bilirubin present in plasma—ie, unconjugated or conjugated—hyperbihru-binemia may be classified as retention hyperbilirubinemia, due to overproduction, or regurgitation hyperbilirubinemia, due to reflux into the bloodstream because of bihary obstmction. 

Sulfonamides are extensively protein bound. If these drugs are administered to mothers immediately before delivery or to the premature or full-term infant while there is physiologic hyperbilirubinemia, they may displace bilirubin from plasma protein, causing severe jaundice or kemicterus (8). 

The levels of GGT in plasma correlate well with elevations of alkaline phosphatase and are a sensitive marker for cholestatic liver disease. Elevations of serum bilirubin are common in end-stage liver disease and obstruction of the common bile duct, but other causes of hyperbilirubinemia are numerous. 

Neonatal hyperbilirubinemia is normally treated by phototherapy. The peak wavelength for photolysis of bilirubin is 450 nm, the same as that for photolysis of riboflavin (Section 7.1). Infants undergoing phototherapy show biochemical evidence of riboflavin depletion, with a significant increase in the EGR activation coefficient. Provision of additional riboflavin to maintain plasma concentrations enhances the photolysis of bilirubin, apparently as a result of reactive oxygen radicals generated by the products of photolysis of riboflavin. 

Favorable results of exchange transfusion in a variety of diseases in adults, for example sickle cell disease, severe clotting disorders, hepatic failure, and acute hemolytic transfusion reactions, have been published (1). Today, however, machine apheresis procedures are more effective and safer for patients requiring exchange of cellular elements or plasma. Exchange transfusion is the most effective therapeutic procedure in the treatment of hemolytic disease of the newborn. Bilirubin removal prevents damage to the central nervous system caused by hyperbilirubinemia. In addition, sensitized erythrocytes are replaced by normally surviving cells and anemia is corrected. 

Sulfonamides should not be given to pregnant women in the third trimester of pregnancy. They can displace bilirubin from plasma albumin and cause kernicterus (bilirubin encephalopathy) (205-208). For the same reason, the administration of sulfonamides to lactating women or premature infants should be avoided. Successful treatment of neonatal hyperbilirubinemia with higher bilirubin concentrations has been established using exchange transfusion and phototherapy. 

Jaundice occurs when plasma becomes supersaturated with bilirubin (>2-2.5 mg/dL) and the excess diffuses into the skin, sclera, and other tissues. The sclera is particularly affected because it is rich in elastin, which has a high affinity for bilirubin. Reddish yellow pigments, particularly carotene and lycopene, may give a yellowish tinge to the skin but they do not usually produce scleral coloration. Hyperbilirubinemia may result from elevation of unconjugated or conjugated bilirubin levels. 

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