Overview
Hypoglycaemia can be normal and transient in normal-term neonates in the first 24 hours of life without any long-term consequences, as they can use alternate substrates (e.g. ketones) to compensate. However, for some infants, this can only compensate up to a certain point. Transient hypoglycaemia is common in the first few hours after birth.
There are no internationally agreed criteria, but many guidelines use the following:
- Term infants and well: ≥2.0 mmol/L
- Unwell or preterm infants: aim for ≥2.6 mmol/L
Other guidelines use the ≥2.6 mmol/L threshold alone.
Causes
Causes can be divided into:
- Poor glucose stores or production:
- Intrauterine growth restriction
- Prematurity
- Birth asphyxia
- Inborn errors of metabolism
- Midline defects (e.g. omphalocele)
- Increased glucose demand:
- Hypothermia
- Haemolytic disease of the foetus and newborn
- Neonatal sepsis
- Respiratory distress
- Seizures
- Polycythaemia
- Hyperinsulinaemia:
- Maternal diabetes mellitus
- Maternal beta-blocker use
- Other endocrine problems:
- Pituitary insufficiency
- Adrenal insufficiency and congenital adrenal hyperplasia
Presentation
Overview
- May be asymptomatic
- Adrenergic symptoms – the body’s ‘reaction’ to low glucose:
- Irritability
- Jitteriness
- Tachycardia
- Pallor
- Neuroglycopenic symptoms – low glucose in the brain:
- Hypothermia may also be seen
Management
Overview
- If asymptomatic:
- Encourage breastfeeding
- Recheck blood glucose in 1 hour, if ineffective, give glucose 10% IV infusion
- If symptomatic or very low glucose (<1 mmol/L):
- Immediately give glucose IV infusion
- If there is a delay in obtaining IV access, consider buccal glucose gel as an interim option while arranging IV glucose or give intramuscular glucagon
- If ≥12 mg/kg/min is required to maintain normoglycaemia, investigate for congenital hyperinsulinism
