Neonatal jaundice is jaundice (yellowing of the skin and other tissues) in neonates.
Neonatal jaundice is obviously jaundice in a neonate. What do those 2 words mean?
"Neonate" is a child in their first month of life - specifically, their first 28 days. "Jaundice" is where a person's skin and eye white's become yellow in color. So it's essentially when a child in their first 28 days of life becomes yellow.
What causes yellowness?
Bilirubin. It gets created when red blood cells are broken down. Usually bilirubin is excreted in bile and urine - which is why urine is yellow! However, at higher level, it seeps out of blood vessels and is flung throughout the body.
Unconjugated hyperbilirubinemia, meaning the problem occurs BEFORE the liver:
Physiological in newborns, as fetal hemoglobin is being rapidly broken down and replaced with adult hemoglobin. Also, hepatic machinery [for the conjugation and excretion of bilirubin] doesn't mature until approximately 2 weeks of age. It is often seen around the 2nd day after birth, lasting 10 days in term infants [up to 204 μmol/L], or 14 days in premature births [up to 225 μmol/L]
Breast milk jaundice, as breast milk may contain factors that keep the baby's liver from breaking down bilirubin. It may run in families
Dehydration → bilirubin will be more concentrated
Formula suppplementation, or malnutrition → breast milk promotes intestinal absorption of bilirubin, so less reaches the liver
Cephalohematoma (i.e. hemorrhage between skul and periosteum, due to rupture of blood vessels crossing the periosteum)
Hemolytic disorders, caused by:
Blood disorders, including:
Sickle cell disease
Conjugated/direct hyperbilirubinemia, meaning the problem occurs:
Biliary atresia (i.e. common bile duct between the liver and small intestine is either blocked or absent)
Bile duct obstruction
That makes sense. But why is this "bilirubin" thing at extremely high levels in babies? What disease do they have?
It can be normal. There's 2 reasons for this. One, because fetal hemoglobin is being rapidly destroyed, and replaced with adult hemoglobin. And two, because the liver, which is supposed to help process the bilirubin to get rid of it into pee, doesn't mature until 2 weeks of age. So it's not surprising that they're naturally yellow for some time.
I see. But how about formula? Does that damage the liver or something?
For some reason, breast milk improves the ability of the tummy to eat bilirubin - we call that absorption. So less reaches the liver.
I see. It's also possible that newborns have disease, right?
Yes. And because they're so young, it's usually "inbuilt" stuff. Diseases they were born with. In particular, we're concerned with blood cells being destroyed super quick. And this can occur in various disorders of blood, including blood cells getting destroyed because they're not their usual shape (i.e. hereditary spherocytosis), or conflict between the mother and baby's blood (i.e. blood type autoantibodies).
Yellow discoloration of the sclera, the face, extending down onto the chest, and then the extremities
Infants whose palms and soles are yellow, have serum bilirubin >255 μmol/l (15 mg/dL), and is more serious
Interfere with feeding
Clinical assessment of color: → jaundiced appearance <24 hours, or >14 days indicates pathological jaundice
Blanching the skin by pressure, so underlying skin and subcutaneous tissue is revealed
Ingram icterometer, where a piece of transparent plastic with 5 transverse strips of graded yellow lines, is pressed against the nose, and matched. Bilirubin level is accordingly assigned
Transcutaneous bilirubinometer, a portable device, which generates a yellow xenon light passing through the subcutaneous tissue. Reflected light returns through an optic fiber, which is measured and assigned a bilirubin level
Serum bilirubin (SBR)>85 μmol/L (5 mg/dL), which is more than double the amount required to cause jaundice in adults (>34μmol/L). Serum bilirubin is differentiated in results into Unconjugated bilirubin ("indirect" and Conjugated bilirubin ("direct" → total bilirubin >331.5 μmol/L, or direct/conjugated bilirubin >34μmol/L indicates pathological jaundice
Why is the threshold for bilirubin double that which is permitted in adults ?
Because the machinery in the liver that processes bilirubin doesn't mature until around 2 weeks of age. That's why it's normal to have bilirubin levels double that in newborns, as supposed to adults .
Hx of illness → infection
FH of jaundice
FH of anemia → hemolytic disorder
FH of neonatal death due to liver disease → liver disease
Intrauterine infection, which can be evidenced by cataracts, small head, hepatomegaly, splenomegaly → infection
Cephalohematoma → hemolytic disorder
Bruising → hemolytic disorder
Signs of bleeding in the ventricles → hemolytic disorder
Maternal blood group and RBC antibodies → hemolytic disease
Using baby's cord blood:
Blood group → hemolytic disease
DAT/Coombs test → ABO incompatibility/hemolytic disease
FBC → hemolysis, unusually shaped RBC's, evidence of infection
CRP → infection
Billirubin with differential (conjugated, unconjugated)
LFT → liver disease
Serum bilirubin normally subsides without intervention. Tx includes:
Frequent and effective feedings → bilirubin is reduced through bowel movements and urination
Bili light (i.e. exposing baby to intensive phototherapy) often used in any newborn w/ serum bilirubin>=360μmol/L → blue light (wavelengths at 458nm) oxidize bilirubin to biliverdin
Sunbathing is also effective, with the advantage of UV-B which promotes vitamin D production. This condition has also been rising due to less time spent outdoors
Exchange transfusions (i.e. exchange of a person's own blood cells with replacement products), in any newborn w/ bilirubin>428 μmol/l
So what would my doctor do if my newborn had neonatal jaundice?
First of all, ensure that the child is getting frequent and effective feeds. That's because bilirubin is excreted both by both number 1's, and number 2's.
How about phototherapy - also known as "the paparazzi" ?
We do not in all cases of neonatal jaundice. Remember neonatal jaundice is defined as bilirubin>255. Well, we only use it if bilirubin >=360, which is more than 40% above the level where we started saying "there's elevated bilirubin here"!
And how does this "paparazzi" work? It's UV light, right? Can't that cause cancer ?
We don't use UV light because it can increase risks of skin moles and cancers. We just use good ole plain blue light . That does not cause cancer !
Extreme jaundice can cause kernicterus (i.e. bilirubin-induced brain dysfunction, because bilirubin is highly neurotoxic), which presents w/ fever, seizure, high pitched crying
So what if a child is a bit yellow. Is it really such a concern?
Yes, because at very high levels, it can cause something called "kernicterus". It's because bilirubin damages the brain - it can cause brain dysfunction.
Common in newborns, affecting >60% of babies in the 1st week of life
Is jaundice in newborns really common?
Yes. 60% will have it in their first week of life. You're not alone .