Hypoxic ischaemic encephalopathy

Question 1

What is hypoxic ischaemic enephalopathy (HIE) ?

Answer 1

Hypoxia = lack of oxygen
Ischaemia = restricted blood flow to the brain
Encephalopathy = malfunctioning of the brain as a result of this

Question 2

Who does HIE usually affect?

Answer 2

Neonates due to hypoxia during birth

Question 3

When is HIE suspected in neonates?

Answer 3

• Acidosis on umbilical artery blood gas
• Poor Apgar scores (a test performed on baby to see how they tolerated birthing process)
• Features of hypoxia
• Evidence of multi-organ failure

Question 4

Causes of HIE?

Answer 4

Anything that leads to reduced O2 to the brain (antenatal, intrapartum or post partum):
- maternal shock
- intrapartum haemorrhage
- prolapsed cord (compresses cord during birth)
- nuchal cord (cord wrapped around baby’s neck)
- placental abruption

Question 5

Describe grades of HIE:
- mild
- moderate
-severe

Answer 5

Mild:
- poor feeding, irritable, hyper-alert
- resolves in 24hrs
-normal prognosis

Moderate:
- poor feeding, lethargic, hypotonic, seizures
- resolve in weeks
- 40% can develop cerebral palsy

Severe:
- reduced consciousness, apnoeas, flaccid, reduced or absent reflexes
- 50% mortality
- 90% develop cerebral palsy

Question 6

Management of HIE?

Answer 6

Supportive care in neonatal unit. Includes:
- neonatal resus
- ventilation
- circulation support, using inotropes
- nutrition
- A-B balance
- treat seizures with anticonvulsants

Therapeutic hypothermia to prevent further damage from secondary reperfusion injury

Follow up by paeds and MDT - assess development and support disability

Question 7

What is intention of therapeutic hypothermia?

Answer 7

Reduce inflammation and neurone loss after hypoxic injury

Reduce risk of:
- cerebral palsy
- developmental delay
- learning disability
- blindness
- death

Question 8

What are the TOBY criteria for theraputic cooling?

Answer 8

• > /= 36 weeks gestation w/ moderate - severe encephalopathy

+ Either:
* APGAR score </= 5
Or
* continued need for ventilation at 10 min after birth
Or
* acidosis (PH <7.00 or base defecit >/= 16 mmol/L

Question 9

When will hypoxic ischaemic encephalopathy develop in a child?

Answer 9

• within 24 hours of bithr
• baby will be unwell at birth - usually needs resucitation