• Kernicterus, or bilirubin
encephalopathy, is a neurologic
syndrome resulting from the
deposition of unconjugated
(indirect) bilirubin in the basal
ganglia and brainstem nuclei.
• Jaundice within first 24 hrs of birth
• A sibling who was jaundiced as neonate
• Unrecognised hemolysis (ABO- or Rh-
• Non optimal sucking nursing
• Deficiency of G6PD
• Cephalhematomas bruising
• East Asian or Mediterranean descent
PREVENTABLE CAUSES OF KERNICTERUS
• The American Academy of Pediatrics has identified potentially preventable causes of kernicterus, as follows:
(1) early discharge (<48 hr) with no early follow-up (within 48 hr of discharge); this problem is particularly
important in near-term infants (35-37 wk of gestation);
(2) failure to check the bilirubin level in an infant noted to be jaundiced in the 1st 24 hr;
(3) failure to recognize the presence of risk factors for hyperbilirubinemia;
(4) underestimation of the severity of jaundice by clinical (visual) assessment;
(5) lack of concern regarding the presence of jaundice;
(6) delay in measuring the serum bilirubin level despite marked jaundice or delay in initiating phototherapy in
the presence of elevated bilirubin levels; and
(7) failure to respond to parental concern regarding jaundice, poor feeding, or lethargy.
PATHOGENESIS • MULTIFACTORIAL
1. Unconjugated bilirubin levels,
2. Albumin binding and unbound bilirubin levels,
3. Passage across the blood-brain barrier, and
4. Neuronal susceptibility to injury.
• The precise blood level above which indirect-reacting
bilirubin or free bilirubin will be toxic for an individual infant
is unpredictable, but in a large series, kernicterus occurred
only in infants with a bilirubin >20 mg/dL.
• Ninety percent of the infants in whom kernicterus developed
were in previously healthy, predominantly breastfed term and
• The duration of exposure to high bilirubin levels needed to
produce toxic effects are unknown.
• The more immature the infant is, the greater the susceptibility
• INITIAL SIGNS
• POOR FEEDING
• LOSS OF MORO REFLEX
• LATER SIGNS
• INFANT APPEARS GRAVELY ILL
• DIMINISHED TENDON REFLEXES
• RESPIRATORY DISTRESS
• OPISTHOTONOS WITH BULDGING FONTANELLE
• TWITCHING OF FACE OR LIMBS
• SHRILL HIGH PITCHED CRY
• ADVANCED STAGE
• CONVULSIONS AND SPASM OCCUR
• AFFECTED INFANTS STIFFLY EXTENDING THEIR ARMS IN AN
INWARD ROTATION WITH THE FISTS CLENCHED.
• RIGIDITY IS RARE AT THIS LATE STAGE.
• Many infants who progress to these severe neurologic signs
die; the survivors are usually seriously damaged but may
appear to recover and for 2-3 months show few abnormalities.
• Later in the 1st yr, opisthotonos, muscle rigidity, irregular
movements, and convulsions tend to recur.
• In the 2nd yr, the opisthotonos and seizures abate, but
irregular, involuntary movements, muscle rigidity, or, in some
infants, hypotonia increase steadily.
• By 3 yr of age, the complete neurologic syndrome is often
apparent; it consists of bilateral choreoathetosis with
involuntary muscle spasms, extrapyramidal signs, seizures,
mental deficiency, dysarthric speech, high-frequency hearing
loss, squinting, and defective upward eye movements.
• Pyramidal signs, hypotonia, and ataxia occur in a few infants.
In mildly affected infants, the syndrome may be characterized
only by mild to moderate neuromuscular incoordination,
partial deafness, or “minimal brain dysfunction,” occurring
singly or in combination; these problems may be unapparent
until the child enters school.
INCIDENCE AND PROGNOSIS
By pathologic criteria, kernicterus develops in 30% of infants (all gestational ages) with untreated hemolytic
disease and bilirubin levels >25-30 mg/dL.
The incidence at autopsy in hyperbilirubinemic preterm infants is 2-16%
Overt neurologic signs have a grave prognosis; more than 75% of infants die, and 80% of affected survivors
have bilateral choreoathetosis with involuntary muscle spasms.
Mental retardation, deafness, and spastic quadriplegia are common.
• Universal screening for hyperbilirubinemia in the 1st 24-48 hr
after birth to detect infants at high risk for severe jaundice and
bilirubin induced neurologic dysfunction.
• Hour-specific bilirubin nomogram
• Physical examination, and
• Clinical risk factors
• The following approach is further recommended:
(1) any infant who is jaundiced before 24 hr requires measurement of total and
direct serum bilirubin levels and, if it is elevated, evaluation for possible hemolytic
(2) follow-up should be provided within 2-3 days of discharge to all neonates
discharged earlier than 48 hr after birth.
• Early follow-up is particularly important for infants younger than 38 wk of
• Parental communication with regard to concerns about infant’s skin color and
behavioral activities should be addressed early.
• Mothers should be advised to nurse their infants every 2-3 hr and to avoid
routine supplementation with water or glucose water in order to ensure
adequate hydration and caloric intake.