Also see guideline on investigation of severe hypoglycaemia

Click here for the Glucose calculator

Hypoglycaemia is important because:

1. It is a common, readily diagnosed and readily treated problem.
2. If untreated, it may cause permanent brain damage.

Definition

Serum glucose <2.6mM.  This is based on the following:

1. Glucose levels within the ‘normal’ range are not necessarily optimal.
2. There is no physiological reason why brain glucose requirements should differ between term and preterm infants, or between the first and subsequent days of life.
3. The aim is to define a level which is safe for all babies, rather than is adequate for most.
4. Altered electrophysiological measurements and poor long-term neurological outcome have been reported in infants with recurrent serum glucose levels <2.6mM.

Diagnosis

1. Monitor at-risk infants
   • All infants <10th centile or >95th centile on customised centile charts
   • If customised centiles are not available, all infants or birthweight < 2.5kg or >4.5kg.
   • Infants of diabetic mothers
   • Stressed infants - i.e. those with birth asphyxia, sepsis, haemolytic disease, respiratory distress or congenital heart disease
   • Infants with possible symptoms
2. When to monitor
   • Measure plasma glucose at 1-2 hours of age, 4 hours, and then 4 hourly, preferably before feeds.
3. How long to monitor
   

   If feeding well	At least 12 hours
   Any recorded hypoglycaemia	At least 12 hours after last low level

Click here to link to the flowchart for management of infants at risk of hypoglycaemia

Treatment

1. All at risk infants (see above) should receive milk feedings (either breastfeed or formula - maternal preference) or intravenous dextrose as soon as feasible, and always within the first 2 hours of life.
2. If glucose below 2.2mM on first testing (1-2 hours) 
       or 2.2-2.6mM after first 2 hours
   feed immediately and recheck glucose within 1 hour.
3. If glucose below 2.2mM after first 2 hours
       or below 2.6mM on more than 2 occasions
       or feeds not tolerated 
   • start IV dextrose 10% at 60ml/kg/day (= 4.2mg/kg/min glucose)
   • continue feeds if possible
   • consider a bolus of 1-2ml/kg 10% dextrose IV
   • recheck glucose within 1 hour
4. Recurrent or persistent hypoglycaemia not responding to above measures - increase IV dextrose concentration or volume e.g. 12.5 or 15% dextrose and continue feeding if tolerated.
5. For small- or large-for-gestational age infants or infants of diabetic mothers on postnatal wards, see separate guidelines.

Continuing Therapy

Continue to monitor glucoses while IV dextrose is being gradually reduced. Rapid reductions in glucose infusion are likely to cause rebound hypoglycaemia.

• Click here to link to the flowchart for weaning of infants receiving dextrose for hypoglycaemia

Persistent or severe hypoglycaemia (requiring more than 10mg/kg/min of glucose or lasting longer than 1 week) may require further investigation and management, e.g. with glucagon, diazoxide, steroids or surgery.
Click here for the Glucose calculator

In an emergency, particularly if there is difficulty in starting intravenous glucose infusion, glucagon 100 to 300ug/kg intramuscularly will stabilise blood glucose in most babies for one to two hours. The dose can be repeated, but subsequent doses are much less likely to be effective. (Glucagon mobilises glycogen stores. After the first dose, stores will probably be depleted).

References