PEDIATRICS
RAAFI UL BASHEER ZARGAR
KERNICTERUS
• Kernicterus, or bilirubin
encephalopathy, is a neurologic
syndrome resulting from the
deposition of unconjugated
(indirect) bilirubin in the basal
ganglia and brainstem nuclei.
RISK • Jaundice within first 24 hrs of birth
FACTORS • A sibling who was jaundiced as neonate
• Unrecognised hemolysis (ABO- or Rh-incompatibility)
• Non optimal sucking\ nursing
• Deficiency of G6PD
• Infection
• 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 near-term
ETIOPATHOGENESIS infants.
• 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 to
kernicterus.
• INITIAL SIGNS
• LETHARGY
• POOR FEEDING
• LOSS OF MORO REFLEX
• LATER SIGNS
CLINICAL • INFANT APPEARS GRAVELY ILL
FEATURES • PROSTRATIONS
• DIMINISHED TENDON REFLEXES
• RESPIRATORY DISTRESS
• OPISTHOTONOS WITH BULDGING FONTANELLE
• TWITCHING OF FACE OR LIMBS
• SHRILL HIGH PITCHED CRY
• ADVANCED STAGE
• CONVULSIONS AND SPASM OCCUR
CLINICAL • AFFECTED INFANTS STIFFLY EXTENDING THEIR ARMS IN AN
FEATURES 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.
RECOVERY
• 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.
• Protocols
PREVENTION
• Hour-specific bilirubin nomogram
• Physical examination, and
• Clinical risk factors
MANAGEMENT
• 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 disease and
(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 gestation.
• 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.
REFERENCES
I. NELSON TEXTBOOK OF
PEDIATRICS, 20TH EDITION
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