Pediatric emergency medicine trisk 0888 0888
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peaks between 3 and 5 days of life in the term infant, rarely exceeds 12 mg/dL,
and requires no treatment.
Gilbert syndrome is a common cause of mild, intermittent, unconjugated
hyperbilirubinemia that occurs in approximately 6% of the population. Patients
with Gilbert syndrome have a partial deficiency of glucuronyl transferase. They
generally present in late childhood with nonspecific abdominal pain, nausea, and
mild jaundice in the setting of an intercurrent illness; there is no
hepatosplenomegaly on physical examination and the remainder of liver function
studies is normal. The serum bilirubin rarely exceeds 5 mg/dL in this benign
cause of jaundice.
Crigler–Najjar syndrome is characterized by the absence or deficiency of the
enzyme bilirubin glucuronyl transferase. Type I is the more severe form,
manifests soon after birth, and is associated with high morbidity and mortality.
Type II is milder, and is caused by an incomplete deficiency of the same enzyme;
it typically presents in infancy or later in childhood. Lucey–Driscoll syndrome is
a form of transient familial hyperbilirubinemia, and is caused by an inhibitor of
glucuronyl transferase in the mother’s serum; the syndrome resolves as the
inhibitor is cleared from the neonate’s blood.
Infants with galactosemia may exhibit an unconjugated hyperbilirubinemia
during the first week of life, whereas older infants with galactosemia tend to have
a conjugated hyperbilirubinemia (see Chapter 44 Jaundice: Conjugated
Hyperbilirubinemia ). Infants with galactosemia typically present with poor
feeding, emesis, abdominal distention, failure to thrive, and hypoglycemia.
Unconjugated hyperbilirubinemia may be the only presenting sign of
congenital hypothyroidism, preceding other manifestations by several weeks. The
mechanism is thought to relate to reduced bile flow. Other signs include poor
feeding, prolonged jaundice, constipation, and hypotonia. Infants of diabetic
mothers are also at increased risk for jaundice, with as many as 19% developing
nonphysiologic hyperbilirubinemia.
Breast milk jaundice occurs in 1% of newborns, and must be distinguished
from breast-feeding jaundice (discussed below); it is associated with the breast
milk itself and typically manifests after the fifth day of life. The underlying cause
of breast milk jaundice is incompletely understood, but is likely hormonally
mediated, and involves inhibition of bilirubin conjugation. Treatment requires
temporary cessation of breast-feeding; however, the mother should be encouraged
to express and store her breast milk during this time, and may resume breastfeeding when the neonatal bilirubin level reverts to normal.
Impaired Bilirubin Excretion
