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Low bacterial degradation of bilirubin (in neonates, the bacterial degradation of bilirubin is reduced because the intestinal flora is not fully developed and this may lead to absorption of unconjugated bilirubin. Increased entero-hepatic circulation (unconjugated bilirubin is reabsorbed from intestine through the process of enterohepatic circulation) This jaundice appears after 24 hours its maximum intensity by 4th-5th day in term & 7th day in preterm with Serum level less than 15 mg / dl and it disappears without any treatment.ĭecreased excretion (ineffective hepatic excretion of unconjugated bilirubin) There are two types of jaundice which are physiological and pathological jaundice. Hepatic excretory capacity is low because of low concentration of the binding protein ligandin in the hepatocytes and also because of low activity of glucuronyl transferase the enzyme responsible for binding bilirubin to glucuronic acid, thus making bilirubin water soluble (conjugation). This is the result of shortened lifespan of fetal erythrocytes and high erythrocyte mass in neonates. A fraction of bilirubin from the stool is reabsorbed into the blood via the portal circulation (enterohepatic circulation).įor neonates, Bilirubin production is elevated because of increased break down of fetal erythrocyte. Conjugated (direct) bilirubin is excreted into bile. Bilirubin (unconjugated or indirect) is bound to serum albumin and transferred to the liver where it is conjugated to glucoronate by glucuronyl transferase. Heme is decomposed into iron which is stored or recycled and biliverdin and bilirubin. Hemoglobin from the decomposed red blood cells is converted into heme and globin. As red blood cells are lysed, they release hemoglobin. Macrophages in the liver and spleen phagocytize damaged red blood cells. With age, red blood cells become increasingly fragile and are damaged by passing through narrow capillaries. The red blood cells are highly produced by bone marrow and has life span of 120 days. However, significant jaundice occurs in 6 % of term babies, the Visible form of bilirubinemia: Newborn skin >5 mg / dl

Hyperbilirubinemia also called jaundice refers to an excessive level of accumulated bilirubin in the blood and is characterized by a yellowish discoloration of the skin, sclerae, mucous membranes and Occurs in 60% of term and 80% of preterm neonates.