Jaundice Flashcards
What is the normal level of bilirubin in an infant
Less than 35umol/l
What is the level where the bilirubin becomes dangerous
Above 200umol/l
Why is a baby most susceptible to jaundice in the first week
This is because in utero the baby keeps its bilirubin unconjugated so that it can be passed to the mother through the placenta thus the baby’s liver enzymes are not as effective at conjugation until the first week. The babies intestines also contain enzymes that deconjugated the bilirubin
What causes increased production of bilirubin 4
- Cephalohaematoma
- Polycythemia
- Infection
- Haemolytic disease
What are 3 possible causes of slow conjugation
- Slow initiation of the enzymes in the liver
- Preterm infants are born before the liver enzymes are ready
- Congenital hypothyroidism: Causes slowing of the maturation of the liver
What are the 2 possible causes of decreased secretion
- Hepatitis: Infection
- Billary atresia
What is meant by physiological jaundice
14 days of increased bilirubin after the birth of the infant
What are the 4 conditions that must occur for ABO hemolytic disease to occur
- The mother should be O
- The father must be A, B or AB
- The infant must be A or B
- The Coombs test must be positive
What is the dose of anti-D immunoglobulins that are given to prevent maternal sensitization
100ug
What makes prem babies more susceptible to high bilirubin levels
They have improperly formed BBB
What are some of the risk factors that place infants at risk for bilirubin encephalopathy 3 and why do these occur
- Hypoxia
- Hypoglycemia
- Infection
These all increase the permeability of the BBB
Which infants should get phototherapy
Any infant with a TSB of above 80 after 6 hours
What are the ranges of phototherapy in a prem infant
- Less than 1250g above 125
- Less than 1500g above 150
- Less than 2000g above 200
What is the main risk factor of phototherapy
The infant can become dehydrated due to the increased passage of stools
What is bronzing and how does it occur
This is when an infant that has an issue in excretion conjugated bilirubin e.g. in biliary atresia is placed under phototherapy and so the unconjugated is converted but there is still no excretion of the conjugated
What is important to remember even after the visible jaundice disappears in phototherapy
That the infant might still have high levels of TSBW
What is the benefit of phenobarbitone
It shows little benefits and makes the infant lethargic
What are the 4 main indications for an exchange transfusion
- A TSB above 400 despite phototherapy
- A TSB in preterm between 250 and 350
- Rapidly rising TSB
- When there is high TSB and the presence of infection, hypoxia, hypoglycemia, or hypothermia
What is considered the normal values for anemia
- Packed cell volume: 45-65%
- HB: 15 - 25g/dL
What is considered an anemia
Below 35%, 12g/dL
Why do premature babies have a fall in their HB 3
- They have underdeveloped kidneys that produce low amounts of EPO
- The fetal RBC has a shorter lifespan
- Infants have low iron because most of the iron transfers in the tritrimester
When should treatment with packed red blood cells be given to a premature baby
If the Hb falls below 8.5 or the PCV is below 25%
What are the 2 criteria for polycythemia
- PVC of more than 65%
- An Hb Above 25g/dL
What are the 3 possible causes of polycythemia
- Chronic fetal hypoxia
- Maternal diabetes
- Over transfusion: This can be twin to twin or iatrogenic
