Neonatology Flashcards
What is jaundice?
What is neonatal jaundice?
The yellow colouring of skin and sclera caused by the accumulation of bilirubin in the skin and mucous membranes.
Neonatal jaundice is caused by hyperbilrubinaemia that is unconjugated (physiological or pathological) or conjugated (pathological).
What is the prevalence of neonatal jaundice in:
a) term infants?
b) preterm infants?
c) breast fed babies at 1 month?
a) 60%
b) 80%
c) 10%
What harmful effect can high levels of bilirubin lead to?
Kernicterus.
What types of jaundice are there?
Which requires treatment?
Physiological jaundice
- jaundice in a healthy baby, born at term, is normal
Pathological jaundice
- jaundice that requires treatment or further investigation
What causes physiological jaundice?
Increased RBC breakdown
- foetal RBC have shorter half lives (90-100 days compared to 120 days in adults)
- in utero, foetus has high Hb concentration that breaks down releasing bilirubin as high Hb is no longer needed
b) Immature liver
- unable to process high bilirubin concentrations
At what time period does physiological jaundice occur?
Starts at day 2-3
Peaks at day 5
Resolved by day 10
Baby remains well and does not require any intervention beyond routine neonatal care.
What can lead physiological jaundice to progress to pathological jaundice?
- If the baby is premature
2. If there is increased RBC breakdown e.g. extensive bruising
What can cause pathological jaundice?
- Haemolytic disease
- e.g. haemolytic disease of the newborn, ABO incompatibility, G6PD deficiency, spherocytosis
- onset <24 hours - Bilirubin above phototherapy threshold
- onset after 24 hours
- likely dehydrated
- increased haemolysis due to bruising/cephalohaematoma - Unwell neonate
- jaundice as a sign of congenital or postnatal infection - Prolonged jaundice
- jaundice for >14 days in term infants OR 21 days in preterm
- consider: infection, metabolic (hypothyroid/pituitarism, galactosaemia), breast milk jaundice, GI (biliary atresia)
What are risk factors for pathological jaundice?
- prematurity, low birth weight, small for dates
- previous sibling required phototherapy
- exclusively breast fed
- jaundice <24 hours
- infant of diabetic mother
How do babies with neonatal jaundice present?
Colour: yellow skin, sclera (determine presence or absence of jaundice)
Drowsy: difficult to rouse, not waking for feeds, very short feeds
Neurologically: altered muscle tone, seizures
Other:
- signs of infection
- poor urine output
- abdominal mass/organomegaly
- stool remains black/not changing colour
What are investigations for neonatal jaundice?
Transcutaneous bilirubinometer (TCB):
- used in >35/40 gestation and >24 hours old for first measurement
- use for all subsequent measurements if level <250umol/L and child has not required treatment
Serum bilirubin:
- if <35/40 gestation, <24 hours old, TCB >250umol/L
- for subsequent levels
Blood group (mother and baby) and DCT
FBC - Hb, haematocrit
As needed:
U&Es - if excessive weight loss/dehydrated
Infection screen - if unwell or <24 hours, cultures if blood, urine, CSF infection suspected, consider TORCH screen
G6PDH - mediterranean or African origin
LFTs - suspected hepatobiliary disorder
TFTs
What is the management for neonatal jaundice?
- Monitor total bilirubin levels and plot on treatment threshold chart
- specific for gestational age of the baby at birth
- age of baby on x-axis
- total bilirubin level on y-axis
- if total bilirubin reaches threshold on the chart, commence treatment to lower bilirubin level - Phototherapy
- Exchange transfusion
- if extremely high levels
- remove blood from neonate and replace with donor blood
1) What is phototherapy?
2) What is double phototherapy?
3) What must be measured once phototherapy is complete and why?
1) Treatment for neonatal jaundice
Converts unconjugated bilirubin into isomers that can be excreted in the bile and urine without requiring conjugation in the liver
Remove clothing down to nappy to expose skin and eye patches to protect the eyes
Light-box shines blue light on to baby’s skin (little or no UV light is used)
2) Double phototherapy involves 2 light boxes
3) Rebound bilirubin measured 12-18 hours after stopping phototherapy to ensure levels do not rise above the treatment threshold again
What is kernicterus?
Brain damage caused by excessive bilirubin levels
Bilirubin can cross the BBB so excessive bilirubin causes direct damage to the CNS
How does kernicterus present?
- less responsive
- floppy
- drowsy
- poor feeding
What complications does Kernicterus cause?
Permanent damage to the nervous system
- cerebral palsy
- deafness
- learning difficulties
Kernicterus is rare now due to effective jaundice treatment
What is hypoxic ischaemia encephalopathy?
Occurs in neonates as a result of hypoxia during birth.
Hypoxia = lack of oxygen Ischaemia = restriction in blood flow to the brain Encephalopathy = malfunctioning of the brain
Some hypoxia during birth is normal but prolonged or severe hypoxia leads to ischaemia brain damage.
What can HIE lead to?
Permanent damage to the brain causing cerebral palsy.
Severe HIE can cause death.
What can cause HIE?
Anything that leads to asphyxia (deprivation of oxygen) to the brain:
- maternal shock
- intrapartum haemorrhage
- prolapsed cord (compression of cord during birth)
- nuchal cord (cord wrapped around neck of baby)
What staging is used to grade hypoxic-ischaemic encephalopathy?
Sarnat staging
What are the grades for Sarnat staging of HIE?
1) Mild - poor feeding, irritable, hyper-alert; resolves within 24 hours; normal prognosis
2) Moderate - poor feeding, lethargic, hypotonic, seizures; can take weeks to resolve; up to 40% develop cerebral palsy
3) Severe - reduced consciousness, apnoeas, flaccid and reduced/absent reflexes; up to 50% mortality; up to 90% develop cerebral palsy
How are patients with HIE managed?
- specialists in neonatology on neonatal unit
- supportive care with neonatal resuscitation and ongoing optimal ventilation, circulatory support, nutrition, acid base balance and treatment of seizures
What are the risk factors for hypoglycaemia in a neonate?
- poor feeding
- infection ie. sepsis
- maternal drugs e.g. labetalol
- diabetes
- prematurity
- preterm
- small baby (low brown fat so use glucose for energy instead)
Who does necrotising enterocolitis affect?
Premature neonates