Part D: Blood

Neonatal Jaundice and Hemolytic Disease of the Newborn

INTRODUCTION

Neonatal jaundice, implying a yellow color of the skin and mucous membranes due to bilirubin deposition, occurs in about 60% of infants and even more often in those exclusively breast feeding. In most cases, the jaundice will be mild or moderate, and the total serum bilirubin (TSB) will not endanger the newborn infant. Occasionally, the TSB may increase to potentially dangerous levels and require treatment with phototherapy or rarely exchange transfusion to offset any further increase. Rarely, the TSB may rise to hazardous levels, at which bilirubin may cross the blood-brain barrier and enter the brain cells. The result will be the complication of acute bilirubin encephalopathy (ABE), in many cases with the devastating chronic sequela of choreoathetotic cerebral palsy known as kernicterus, or death. Despite attempts to eliminate this condition, kernicterus, although a rare condition, is still with us and accompanies us into the third millennium. Many cases should be preventable. Because the implications for affected individuals are lifelong, the public health aspects are necessarily of major importance. Understanding of the metabolism of bilirubin and the pathophysiology of hyperbilirubinemia are crucial to the prevention of this condition, as discussed in this chapter.

EPIDEMIOLOGY

Was There a Disappearance and Resurgence of Kernicterus?

Some authors refer to a disappearance and then resurgence of reported cases of kernicterus in Westernized countries during the last decades.^{1, 2, 3, and 4} Others opine that the condition never completely disappeared and is still being seen, both in countries with advanced medical systems and in developing countries.⁵ There can be no doubt that widespread use of the 2 mainstays of treatment of hyperbilirubinemia, exchange transfusion and phototherapy, along with immune prophylaxis of Rh isoimmunization, have prevented many cases of extreme hyperbilirubinemia. If the condition did indeed disappear, however, there can be no explanation for the cases of kernicterus still occurring due to conditions including glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and direct antiglobulin titer (DAT) positive ABO isoimmunization, conditions that, in themselves, did not disappear.^6,7

In favor of the resurgence theory, following a period during which few cases of kernicterus were reported, several case reports were published from the United States,^{8, 9, and 10} followed by reports of the US-based Kernicterus Registry.^7,11 In Denmark, Ebbesen¹² did find cases of bilirubin encephalopathy between 1994 and 2001, whereas in a nationwide search, he uncovered no cases during the 20 years preceding 1994.

On the other hand, in the United States, Burke et al reported a 70% decrease in the number of hospitalizations between 1988 and 2005 of neonates diagnosed with kernicterus.¹³ Brooks et al found a constant incidence of kernicterus in California occurring during 2 time epochs: 1988–1993 and 1994–1997.¹⁴ On a national ...