Neurology

Question 1

Criteria for Hypothermia for HIE

Answer 1

1. Gestation: 35 weeks or older

2. Age: less than 6 hours since birth

3. Evidence of asphyxia by at least 2 of the following

• APGAR <6 at 10 mins or ongoing need for resuscitation
• Any acute perinatal event that may cause HIE
• Cord arterial pH <7.0 or cord BE<-12 mmol or cord arterial lactate >9.4mmol/l

4. Evidence of moderate or severe HIE

• seizures or,
• 3 of 6 criteria or,
• Neonatologist concern

Question 2

Pathophysiology HIE

Answer 2

• Reversible hypoxic ischaemic global insult
• Absent cerebral glucose/oxygen reduces ATP, producing lactic acid and neuro excitotoxicity causing necrosis and cell death
• Neuronal cell death in phases
  
  • Acute phase: hypoxic ischaemic event
  • Latent period (up to 6hrs): return of aerobic metabolism and ongoing inflammation/cell death
  • Secondary phase (hrs to days): cytotoxic oedema, mitochondrial failure and excitotoxicity (encephalopathy)

Question 3

Effect of Therapeutic Hypothermia

Answer 3

• Alters course of apoptosis
• decreases cellular metabolic rate
• reduces the release of neuro-excitatory AAs and free radicals

Evidence: cooling reduces mortality or major neuro-developmental disability at 18mo without increasing the disability in survivors.

Question 4

Contraindications to Therapeutic Hypothermia

Answer 4

Absolute Contraindication:

Question 5

Germinal Matrix

Answer 5

location: subependymal, subventricular region

timing: 8 to 28 weeks gestation and involutes from 24 weeks, and is gone by 34 weeks

function: source of neuron and glial cells that migrate radially outward

Question 6

Risk factors for IVH

Answer 6

Linked to fluctuation in cerebral blood flow.

• IVH
• Community hospital
• Sepsis eg. chorio
• Non-optimal initial stabilisation
• RDS
• Pneumothorax
• Hypotension
• Asphyxia
• PDA
• Coagulopathy

Question 7

Screen IVH

Answer 7

For babies <32 weeks or <1500g

• 50% occur within the first day
• 90% occur within the first 3 days

If IVH not diagnosed by 1 week then it is unlikely to occur

Question 8

Papile Grading System

Answer 8

Grade IV is more likely to be a venous infarction than extension of grade III IVH.

Question 9

Post haemorrhagic hydrocephalus

Answer 9

incidence: 1/3 of IVH but 2/3 spontaneously resolve within 4 weeks

Question 10

Outcome IVH

Answer 10

Grade 1/2: minimal increased risk

Grade 3: 1/3 major impairment

Grade 4: 3/4 major impairment

PHH: 90% neurodevelopmental impairment, 14% seizures, 9% visual problems, 6% SNHL