*Jaundice Flashcards
What is jaundice?
Yellow discolouration of the skin and sclera due to an increase in unconjugated bilirubin in the blood and tissues.
It is usually benign
How does jaundice appear?
Yellowing of the skin and conjuctiva
What is the process of bilirubin?
SPLEEN - unconjugated (fat-soluble) bilirubin is a by-product of RBC breakdown
CIRCULATION - free, unconjugated bilirubin attracted to fatty tissue, to brain (high levels cause KERNICTERUS)
LIVER - unconjugated bilirubin transported to liver where it becomes conjugated (water soluble)
GALL BLADDER - conjugated bilirubin transported to gall bladder
BILE DUCT - conjucated biliruibin is excreted in bile excreted into GI tract
INTESTINES - becomes urobilin (through bacteria) which is further metabolised into urobilinogen (reabsorbed from gut and extrected via urine) and stercobilinogen (excreted in faeces)
EXCRETED - in faeces, reabsorbed from gut and excreted via urine
What is kernicterus?
Accumulation of billirubin in the brain resulting in irreversible damage (neurological deficits, seizures, abnormal reflexes and eye movements)
- Not all bilirubin binds to albumin
- Free unbound bilirubin is attracted to fatty tissue
- Brain is fatty - can cross blood-brain barrier
= irreversible neurological injury
Worst outcome of high billirubin
What is the pathophysiology (causes) of jaundice?
- Fetal Hb levels are higher and have shorter lifespan
- Immature liver
- May have reduced albumin binding sites owing to other reasons (e.g. acidosis, prematurity)
- Fetal gut - delayed emptying (conjugated bilirubin may become unconjugated bilirubin and then be reabsorbed into system)
What is the treatment for hyperbilirubinaemia?
Phototherapy
What is physiological jaundice?
From 3-10 days
Baby is well
What is pathological jaundice?
Occurs within first 24hrs of life or beyond 2 weeks.
Significant and early jaundice due to more sinister underlying problem (e.g. HDN, ABO incompatability, Rh incompatability, metabolic disorders)
Begin immediate workup for possible sepsis and blood group incompatibility (HDN)
What is breastfeeding jaundice?
Exaggerated physiological jaundice - Associated with poor intake/weight gain
- Appears between 48-72hrs of life
- Peaks at D3-5
What are risk factors (warning signs) for jaundice?
- Birth trauma (especially bruising)
- RhD negative
- Blood group incompatibility (Maternal O)
- Pre-term
- Delayed feeding
- Delayed meconium passage
- Family history
Jaundice: What observations would you undertake?
- Cephalocaudal exam
- TCB / SBR
- Wet (?concentrated) and dirty nappies
- ?Lethargy
- Pre-kernicterus behavious - restlessness, poor muscle tone, seizures
- Feeding
What is Kramer’s rule?
Jaundice appears first in the face and progresses to trunk and extremities.
- Use natural light
- Blanch the skin
- Look at conjunctiva/gums in darker skinned babies
Jaundice: When to refer?
- If SBR is over treatment line
- If sleepy
- If not feeding
- If within first 48hrs of life
No need to refer if jandice is light, baby is alert and feeding, jaundice is fading on daily observation
Jaundice: What tests are involved?
- TcB? (transcutaneous bilirubin)
- SBR (serum bilirubin)
- Blood group
- Direct Coombs (DAT): detects level of maternal antibodies
Treatment for jaundice?
Phototherapy degrades unconjugated bilirubin to water-soluble products
Biliblanket
In severe cases: exchange transfusion
Treat underlying disorder
What is billirubin?
A by product of Hb through the breakdown of haem
What is the Kleihauer test?
A blood test which estimates the number of fetal cells in the sample of maternal blood.
50+ fetal cells is considered high
If present - 625IU of Anti D
What is Direct Coombs test?
Cord blood taken to meaure the level of maternal antibodies on fetal RBCs.
Sometimes called a direct antiglobulin test (DAT)
What is an SBR?
Blood test measuring the amount of billirubin in the blood
When might you suspect pathological jaundice?
Jaundice in first 24 hrs
Jaundice beyond physiological limits
CB >2mg or 20% of total
Rise of >5mg/24hrs or 0.5mg/dl/hr
Beyond 2 weeks
Signs of underlying illness
How to differentiate between pathological and physioligical jaundice?
Time of onset
* Pathological earlier - within first 24 hrs of life or last longer than normal 1-2 weeks
Bilirubin levels including peak levels
