Jaundice Flashcards
bilirubin is derived from ___
the heme from old or damaged RBCs is broken down into bilirubin and iron
___ transports the bilirubin to the liver where it undergoes two enzymatic processes to conjugate it into a water-soluble form.
Albumin
Describe bilirubin clearance
- albumin transfer unconjugated bilirubin to liver
- Bilirubin undergoes 2 enzymatic processes to conjugate it into a water soluble form
- The liver then stores it as bile and excretes it into the intestine where it aids in fat digestion
*normal intestinal flora make conjugated bilirubin non-resorpable
What is is responsible for the yellow to green to brown color of stool.
bilirubin stored as bile in liver then excreted into intestintes where it aids in fat digestion
___ keeps the bilirubin in bile in its water-soluble form making it non-resorpable
The normal intestinal flora
Until the dual enzymatic process in the liver is completed, the bilirubin is __ and ___
unconjugated and fat-soluble.
In laboratory analysis, unconjugated bilirubin reacts with reagents ___, so on laboratory reports it will be referred to as__ bilirubin. Once the bilirubin is conjugated, it reacts ___ with laboratory reagents, so is referred to on laboratory reports as bilirubin.
indirectly
indirect
directly
direct
ALL newborns develop physiologic jaundice to some degree. It rarely rises above ___ of bilirubin, and has only ___ and ___, and causes no problems for the newborn.
13mg/dl
mild skin jaundice and scleral icterus
Why do all newborns have some degree of physiologic jaundice
- Infants are born with a high RBC count, to compensate for their somewhat hypoxic state in utero. These begin to breakdown fairly soon after birth so there is naturally a increased amount of bilirubin being produced
- increased fatty acid intake interferes with albumin transport, which is more of a problem for breast fed infants, but occurs to some degree with all infants.
- the second enzyme, UDP-glucuronyl transferase is somewhat slow in functioning in the initial days of life, so unconjugated bilirubin will build up in the serum
- The bile duct does not begin secreting immediately, so there is some degree of stasis that occurs at this level with conjugated bilirubin.
- the neonate intestine is a sterile environment until they have been feeding for a few days. Without the intestinal flora, the conjugated bilirubin in the bile is resorbed, leading to a increase in the total serum bilirubin.
____ intake interferes with albumin transport, which is more of a problem for breast fed infants, but occurs to some degree with all infants.
increased fatty acid
____ is somewhat slow in functioning in the initial days of life, so ___ bilirubin will build up in the serum.
the second enzyme, UDP-glucuronyl transferase
unconjugated
the neonate intestine is a sterile environment until they have been feeding for a few days. Without the intestinal flora, the ___ bilirubin in the bile is resorbed, leading to a ___
conjugated
increase in the total serum bilirubin.
Risk factors for neonatal jaundice
- Breastfeeding
- Prematurity
- Dehydration
- Asian ancestry- due to less amount of, or less effective UDP-glucuronyl transferase
- Hemolytic processes
- Maternal diabetes/ hypoglycemic infant
- Infection- poor bile excretion and increased RBC breakdown
- Obstructed bile duct (biliary atresia)
Increased fatty acids interfere with:
- albumin transport of bilirubin to the liver
- UDP glucuronyl transferase
*Fatty acids are high in breast milk
Describe why neonates can get break milk jaundice
- increased RBC breakdown
- fatty acids interfere w/ albumin transport of bilirubin to the liver and UDP glucuronyl transferase
- poor biliary excretion of conjugated bilirubin due to lack of breast milk in first 3 days of life leading to dehydration
___ is the leading cause of neonatal jaundice, and can lead to bilirubin levels high enough to require treatment
Breast milk jaundice
*Generally, we try, and are successful at keeping infants breastfeeding. We just have to play a waiting game, and be ready to provide treatment to bring the bilirubin levels down if necessary
Common causes of increased breakdown of RBC and the additional release of unconjugated bilirubin that can lead to pathologic neonatal jaundice
- Hemolytic Disease
- ABO incompatibility (MC)
- G6PD deficiency
- Extravascular blood (ie. cephalohematoma)
- Hereditary spherocytosis
- Significant tissue bruising during delivery
How do you determine if ABO incompatibility (hemolysis) is causing the neonatal jaundice
- In these cases, the mother is O+ and the baby is not.
- A Coombs test can tell you if the baby’s RBCs are carrying antibodies which mark them for destruction.
*-Indirect coombs- AB in serum, direct coombs- AB on RBC so immune system is going after it
**Mother has to be O+
G6PD deficiency most commonly occurs in who
is usually a disease of males of African or Mediterranean descent and the stress of birth, combined with this enzymatic deficiency, will result in hemolysis.
Causes of pathologic neonatal jaundice that results in high unconjugated or indirect bilirubin
- increased breakdown of RBC
- Decreased serum albumin (common in premature infants)
- Competitive albumin-binding (ie. sulfa drugs- MC w/ UTIs during preg.)
- infant hypoglycemia
- UDP glucuronyl transferase deficiency
If the infant had hypoglycemic episodes in the nursery, it will not be able to make the necessary amounts of ___
glucuronic acid (substrate)
Neonatal hypoglycemic occurs due to __ or __
maternal diabetes or infections in the infant.
Causes of UDP glucuronyl transferase deficiency
- Crigler Nayjar disease
2. Gilbert’s Syndrome
Causes of pathologic neonatal jaundice that results in high conjugated or direct bilirubin
- Cholestasis
- Biliary atresia***
- Galactosemia
- Inborn errors of metabolism
- Down Syndrome
- Infection (bacterial and viral)
- CF
- hypothyroidism
Biliary atresia needs to be corrected by ___ of life in order to avoid liver failure necessitating a liver transplant.
the second month
Often the newborn screen is not back when these infants are evaluated, so the index of suspicion for a ___ needs to remain high, in these cases with high direct bilirubin levels
metabolic defect
__ and __ both cause slow gut motility resulting in decreased bile clearance
Cystic fibrosis and hypothyroidism
**If they have passed meconium, Hypothyroidism and CF are less likely
Jaundice which appears on the ___ day of life is always pathologic and you will want to work quickly to determine the underlying cause.
first day of
What viruses can cause high direct bilirubin
- EBV
- CMV
- Hepatitis
- HSV
What history is important to obtain when assessing neonatal jaundice
- Intake amount and type (BM or formula)
- Urine output
- Stooling pattern and color
- Ethnicity
- Maternal blood type
- postnatal period/infections
- family history of red cell abnormalities or metabolic disorders or significant neonatal jaundice in other infants
What EXAM is important to obtain when assessing neonatal jaundice
- Calculate weight loss percentage
- Hydration status/cap refill
- Neurologic status
- Extravascular blood/bruising
- Skin color by blanching on sternum
Describe the normal stooling and urinating pattern of neonates
Neonates usually urinate every 2 hours after the first day of life, and stool with every feeding.
-have a wet diaper for every day of life (1 wet diaper on day 1, 2 wet diapers on day 2, etc.)
Why is assessing the stool color important for the neonatal jaundice work up
The color of the stool helps to ascertain the presence of bile and transitions from the black tar of meconium to the dark green of transitional stool, to the yellow of bile-containing stool.
How can you assess how much breastmilk an infant is getting
- by eliciting a history of breast engorgement before feeding followed by a sensation of emptying during feeding.
- Again, most moms do not have a milk supply until late on day 3 to early on day 4.
- Ask about latching and satiety of the infant and determine the frequency and duration of feeding
most moms do not have a milk supply until ___
late on day 3 to early on day 4
How often should neonates feed?
Young neonates need to be awakened to feed every 2 hours and sometimes this contributes to some dehydration are not aware of this and allow them to just continue sleeping.
How do you calculate neonate weight loss percentage
using the difference between birth weight and current weight (make sure it is naked), divided by the birth weight.
How much weight should a neonate lose initially?
- Infants, especially breast fed, will lose some of their weight in the initial week, and then regain it by 2 weeks of life.
- It is acceptable for newborns to lose 2-3% of their birth weight per day, through Day 3, when they should begin to regain when maternal milk supply begins.
- Formula fed infants rarely lose any weight.
How can you assess skin jaundice
*It is often difficult to see jaundiced skin in a newborn, because their skin is fairly red, if they are fair to medium skin color by ethnicity.
It is helpful to apply pressure to their skin to blanch out the red color giving you a second or two to assess the underlying skin color for jaundice.
-If you have difficulty assessing the skin in the time it takes capillary refill to return the ruddy color to the skin, use a microscope slide to apply pressure to blanch their skin.
How do you assess a neonates neuro status
by assessing their response to stimuli such as being cold, bright lights, or their extremities being pulled on.
*This is not to guide your investigation into the cause of their neonatal jaundice
Remember that neonatal jaundice has a two-pronged approach- ascertaining and correcting an underlying pathology and reducing the high bilirubin levels in order to avoid the development of ___
kernicterus.
What is kernicterus
Kernicterus is the deposition of bilirubin in the brain leading to serious neurologic injury which is what you are assessing in the neurologic exam. An additional consequence of kernicterus is permanent hearing loss.
An additional consequence of kernicterus is ___
permanent hearing loss.
Describe the dual approach to neonatal jaundice management
- DETERMINE if a pathologic cause exists
- REDUCE the serum bilirubin levels
*Regardless of cause, without reduction of high bilirubin levels, the child may suffer kernicterus, leading to hearing impairment or serious neurologic injury
When assessing if the infant needs reduction in the bilirubin levels due to any cause, we use this wonderful website of ___ which you can easily locate using any search engine. Once you have the ___ level of the infant, you can input birth time and time of blood draw, or use the infant’s age in hours and the bilirubin level into the calculator.
bilitool.org
total bilirubin
What are reasons for starting phototherapy sooner
- premature
- showing signs of neurotoxicity
- pathologic cause of jaundice
Bilirubin deposits in ___ tissue.
-Describe the order that jaundice first appears and resolves
keratinized
- so begins first in the skin of the face and then descends caudally, later depositing in the sclera.
- It resolved in the reverse direction
Some of us assess the degree of jaundice by ____ as a guide for how high the serum bilirubin levels are with ___ and __ being a threshold for getting serum bilirubin levels
determining how far down the body it has developed
abdomen and thighs
If you have a ___, you can get a sense of their total bilirubin level from that
transcutaneous bilirubin meter
*If abnormal, will need serum bilirubin confirmation
You will often need a ___ level in a jaundiced baby. In neonates with rapidly rising bilirubin levels, or a concerning history or exam, further testing will be needed
serum total bilirubin
Use the bilitool to help you with treatment decision-making, which may include
- discharging to home with every 24 hours serum bilirubin rechecks
- home bilirubin blanket or
- light phototherapy with every 24 hour rechecks, or
- inpatient care.
Every case is different, but we tend to use inpatient care for those:
- pathologic jaundice or
- neurologic toxicity is a concern, or
- if follow-up is an issue.
You will often need a serum total bilirubin level in a jaundiced baby. In neonates with rapidly rising bilirubin levels, or a concerning history or exam, further testing will be needed including:
- CBC w/ peripheral smear
- Reticulocyte count
- Fractionated serum bilirubin (total, direct, indirect)
- Coombs test- direct and indirect
- Not usually done initially: tests for infection (urine, TORCH titer)
-___ is the last to show up as jaundice and the last to go away
Scleral icterus
-Transcutaneous bili can be as far off as ___ so add __ to the transcut. And see if it is still in normal range
3
3
