Click here to view. Differentiation between physiologic jaundice, which is seen in many infants during the first week of life, and pathologic jaundice is essential because pathologic jaundice is a sign of a more serious condition jaundice, babies, jondice, bilirubin. Pathophysiology Physiologic versus pathologic jaundice Physiologic jaundice is characterized by unconjugated hyperbilirubinemia that peaks by the third or fourth day of life in full-term newborns and then steadily declines by 1 week of age. Subsequent Rh-positive fetuses may develop hemolysis. Other minor blood group incompatibilities also can cause hemolysis and jaundice.
ABO incompatibility is the most common type of isoimmune hemolytic disease.
This type of hemolysis is relatively mild. G6PD deficiency , a sex-linked disease, is an important cause of hyperbilirubinemia and anemia in infants of Greek and Asian descent. Abnormalities of the red blood cell membrane , such as spherocytosis and elliptocytosis, may cause hyperbilirubinemia. Alpha thalassemia may occur in the neonatal period. Decreased bilirubin excretion Delay in intestinal transit time , because of decreased motility or bowel obstruction, increases the enterohepatic circulation.