Pediatric Jaundice Flashcards
Define “jaundice”.
~The yellow-orange tint found in the sclera and skin of infants secondary to hyperbilirubinemia
~Visible jaundice early in life usually means that the TSB is at least 5mg/dL
~2/3 of newborns will appear clinically jaundiced (for whatever reason) during their first weeks of life
~DDx of jaundice in newborns is lengthy!
Discuss the importance of distinguishing between conjugated (direct) and unconjugated (indirect) hyperbilirubinemia in a jaundiced infant.
- The differentials diagnoses change.
- Hyperbilirubinemia, more precisely hyperbilirubinemia due to the unconjugated fraction, may cause bilirubin to accumulate in the gray matter of the central nervous system, potentially causing kernicterus.
Explain in general terms the direct and indirect Coombs test.
~ABO incompatibility may occur if mom’s blood type is O and the baby’s blood type is A or B or AB
~Pregnant women get a prenatal antibody screening with a Coombs test. It checks the mother’s blood to see if there are antibodies that could pass to and harm her unborn baby.
~If mom is type O or if mom is Rh(D) negative, the infant’s cord blood should be evaluated for this by using a direct antibody (Coomb’s) test
Access and use BiliToolTM when presented with a newborn’s gestational age, day-of-life, and bilirubin levels.
~You put in the gestational age, day-of-life, and bilirubin levels and it will give you a risk stratification
~Will also tell you if they can go under the bili lights!
Explain the significance of stool passage as it relates to enterohepatic circulation and bilirubin in a newborn.
Not much mentioned about this in his lecture about this but…
Decreased intake, decreased passage of stool –> higher levels of unconjugated bilirubin.
Additionally, the presence of pale stools and dark urine suggests an obstructive or post-hepatic cause as normal feces get their color from bile pigments.
Determine which infants are at risk for hyperbilirubinemia secondary to blood group (ABO) and Rh incompatibility when presented with maternal ABO and Rh status.
~May occur if mom’s blood type is O and the baby’s blood type is A or B or AB
~ABO and Rh(D) testing should be done on all pregnant women
~If mom is type O or if mom is Rh(D) negative the infant’s cord blood should be evaluated for a direct antibody (Coomb’s) test
~If mom is not O and is Rh positive, cord blood does not need to be tested
List the most common causes of unconjugated hyperbilirubinemia in a newborn baby (4 major categories of this).
Unconjugated:
1. Increased bilirubin production: ~Erythrocyte-enzyme deficiencies ~Blood group incompatibility (ABO)* ~Structural defects in RBC’s ~G6PD deficiency
- Deficiency of hepatic uptake:
~Albumin site overload - Impaired conjugation of bilirubin:
~Gilbert syndrome
~Crigler-Najjar syndrome type I
~Severe UGT1A1 deficiency - Increased enterohepatic circulation:
~Decreased intake, decreased passage of stool
Differentiate between Crigler-Najjar type I and type II in terms of bilirubin-uridine diphosphate glucuronyltransferase (UGT1A1) activity and potential long-term outcome.
Crigler-Najjar type I:
~No UDP glucuronosyltransferase 1-A1 expression can be detected in the liver tissue.
~Outcome is grim
Crigler-Najjar type II:
~UGT1A1 is present at reduced but detectable levels (typically <10% of normal), because of single base pair mutations.
~Prognosis is better
List the most common causes of conjugated hyperbilirubinemia in a newborn baby, although it should be noted that in general, conjugated hyperbilirubinemia in a newborn baby is rare.
Conjugated:
- UTI or sepsis
- Biliary atresia/cholestasis
- Hypothyroidism
- Galactosemia
What are the two phases of bilirubin induced neurologic dysfunction (BIND)/kernicterus? What symptoms are seen in each of the two phases?
Phase 1: First year of life ~HypERtonic ~Active DTR’s ~Obligatory tonic-neck reflexes ~Delayed motor skills
Phase 2: ~Choreoathetoticcerebral palsy ~Ballismus ~Tremor ~Upward gaze ~Dental dysplasia ~Sensorineuronalhearing loss ~Cognitive impairment
Recognize the signs/symptoms of bilirubin toxicity in a neonate. What happens in each of the three phases?
Acute bilirubin toxicity is when you have a super duper high unconjugated bilirubin level in the neonate. It is lipid soluble and is starting to cross blood-brain barrier.
Three Phases: Phase 1—the first 1-2 days ~Poor suck****** one of the first complaints you will hear about! Do not blow it off! ~High pitched cry ~Stupor ~Hypotonia ~Seizures
Phase 2—middle of the first week of life ~Hypertonia of extensor muscles ~Opisthotonus ~Retrocollis ~Fever
Phase 3—after the first week of life
~Hypertonia
Discuss the difference between breast-feeding (“lack of breast milk”) and breast-milk jaundice.
Breastfeeding vs. Breast Milk Jaundice:
~Breast feeding jaundice is more a function of dehydration and decreased excretion of bilirubin the stool (more supply related)
~Breast Milk jaundice is due to the presence of bilirubin deconjugating enzymes in milk
Explain how phototherapy decreases bilirubin levels in infants undergoing treatment for hyperbilirubinemia.
~Isomerized bilirubin, making it water soluble
~Must expose as much surface area of bare skin as possible to the lights
~Light is in the blue-green spectrum
List the 3 major signs/symptoms of biliary atresia in a neonate.
Biliary atresia:
~Progressive and destructive inflammatory process affecting both the extra-and intrahepatic biliary tree
~Development of jaundice in the first few post-natal weeks
S/Sx:
- Cholestatic jaundice
- Hepatomegaly
- Acholic stools
Describe the pathophysiology behind bilirubin induced neurologic dysfunction (BIND)/kernicterus. Hint: blood-brain barrier.
~Unconjugated hyperbilirubinemia during the neonatal period describes the history of nearly all individuals who suffer from kernicterus.
~It is thought that the blood–brain barrier is not fully functional in neonates and therefore bilirubin is able to cross the barrier.
