Pediatric Jaundice - Newman Flashcards
what is heme broken down into?
biliverdin and CO
what is biliverdin reduced to?
bilirubin
how do you get free unconjugated bilirubin?
albumin-binding sites are saturated, or unconjugated bilirubin is displaced from albumin by medicine
is unconjugated bilirubin lipid soluble?
yes, so it can cross the BBB
high hematocrit and RBC volume
- RBC with shorter life span
- inadequate conjugation of bilirubin by the liver due to immaturity of hepatic glucuronosyltransferase
newborns
- lots of unconjugated bilirubin present in their blood!
what is the most common type of bilirubin involved in neonatal hyperbilirubinemia
UNconjugated
- a result of hemolysis of RBC’s
levels of what, increase rapidly in the first few weeks after birth?
UGT1A1
- initially the level is very low, overwhelming the amount of unconjugated bilirubin presented in the liver
what enzyme is located in the intestine, and deconjugates bilirubin (making it water soluble), allowing it to be reabsorbed from the gut into the blood?
beta-glucuronidase
- the rest is excreted in the stool
visible jaundice early in life usually means that the transcutaneous serum bilirubin (TSB) is at what level?
5 mg/dL
what causes jaundice?
hyperbilirubinemia
caused by dehydration and decreased excretion of bilirubin in the stool (more supply related)
breast FEEDING jaundice
due to the presence of bilirubin deconjugating enzymes in milk
breast MILK jaundice
conjugated hyperbilirubinemia is always what?
pathologic!
what causes unconjugated hyperbilirubinemia?
- increased bilirubin production: erythrocyte-enzyme def, ABO incompatibility, RBC structural defects, G6PH def
- hepatic uptake def
- impaired conjugated: Gilbert synd, Crigler-Najjar type 1, severe UGT1A1 def
all moms that are type O blood, or Rh (D) neg must have what test done?
a direct coombs test
- tests for autoimmune hemolytic anemia (erythroblastosus fetalis)
also check the infant’s cord blood
what causes conjugated hyperbilirubinemia?
- UTI or sepsis
- **biliary atresia/cholestasis*
- hypothyroidism
- galactosemia
first 1-2 days of life
- poor suck
- high pitched cry
- stupor
- hypotonia
- seizures
phase 1 of acute bilirubin toxicity
middle of first week of life
- hypertonia of extensor muscles
- retrocollis
- fever
phase 2 of acute bilirubin toxicity
after the first week of life
- hypertonia
phase 3 of acute bilirubin toxicity
first year of life
- active DTR’s
- obligatory tonic-neck reflexes
- delayed motor skills
phase 1 of BIND (bilirubin induced neurologic dysfunction)
KNOW this phase!
- choreoathetotic cerebral palsy
- ballismus (spontaneous movements)
- tremor
- upward gaze
- dental dysplasia
- sensorineuronal hearing loss
- cognitive impairment
phase 2 of BIND
what do you assess for icterus?
the sclera and mucous membranes
- jaundice in the first 24
- ABO incompatibility with positive DAT
- hemolytic disease (G6PD, hereditary spherocytosis)
- gestational age 35-36 weeks (preterm)
- previous sibling requiring phototherapy
- cephalohematoma or bruising (from vaccuum delivery)
- exclusive breatfeeding (esp if it’s not going well)
- east Asian race
risk factors for severe hyperbilirubinemia
what are the 3 biggest risk factors for hyperbilirubinemia?
- prematurity
- high hematocrit at birth
- ABO incompatibility
what is the measurement for excessive jaundice in infants?
jaundice to neck = 5
jaundice to waist = 10
jaundice to toes = 15
what tests need to be run when TSB increases rapidly or baby is unexpectedly jaundiced upon initial exam?
- BT and DAT (coombs)
- CBC and peripheral smear
- conjugated bili level
- reticulocyte count
- repeat TSB in 4-24 hours
what labs should be run when conjugated bilirubin is elevated?
- UA
- blood cultures
- consider intra-hepatic or post-hepatic abnormalities
what labs should be run when baby has prolonged jaundice (greater than 3 weeks)?
- TSB, always order fractionated! (need unconj and conjugated)
- check newborn screens (hypothyroid, galactosemia)
if baby has jaundice for 2 months, what disease should you consider?
Gilberts
- most DC babies at 48 hours of life
- bilirubin greater than 24 hours of life
- DAT in babies born to Type O and Rh neg moms
- folluw up of the newborn within 2 days of DC
hospital protocol
- increase frequency of feedings
- continue breast feeding
if inadequate oral intake, excessive weight loss (>12% of birth weight), or dehydration, the baby should receive supplemental breast milk/formula
tx for mild jaundice, not a candidate for phototherapy
NOTE: exchange transfusion is considered when bili is >25 mg/dL or when symptoms of acute encephalopathy are present
what makes bilirubin water soluble?
isomerization (H-bonds to water, rather than internally H-bonded)
progressive nad destructive inflammatory process affecting both the extra and intrahepatic biliary tree
- development of jaundice in the first few post-natal weeks
- cholestatic jaundice, hepatomegaly, acholic stools
conjugated hyperbilirubinemia
- “giant cell” hepatitis
- prolonged cholestatic jaundice
- liver biopsy shows a very disrupted hepatic architecture
idiopathic neonatal hepatitis
syndromic bile duct paucity or arteriohepatic dysplasia
- AD
- marked reduction of intrahepatic bile ducts
Alagile syndrome
- liver disease resulting from retention of abnormal proteins in the endoplasmic reticulum of the hepatocyte
- most common genetic cause of acute and chronic liver disease in children
- most common genetically caused disorder necessitating liver transplantation in children
a1-AT deficiency
what causes jaundice in older children/adolescents?
obstructive or hepatocellular causes
