Hypoglycaemia in Children

Introduction.

Hypoglycaemia is an abnormally low level of glucose in the blood (less than 4 millimoles per litre or 40 mg/dl) irrespective of age and gestational age.
Most infants with mild to moderate  hypoglycaemia are asymptomatic.
Normal glucose utilization rate is 4-6mg/kg/minute but high-risk infants require 6-10mg/kg/minute.
In the extreme cases of hyperinsulinism, the infants utilize glucose at a rate greater than 10mg/kg/minute.
The following predispose to it:

  • prematurity, intra-uterine growth restriction, hypothermia, perinatal asphyxia, polycythaemia, septicaemia, maternal diabetes, in-born errors of metabolism -galactosaemia, glyogen storage diseases -, liver diseases, haemolytic disease of the newborn, Beckwith-Wiedemann syndrome, nesidioblastosis and other pancreatic tumours.

Clinical features

Mild cases of hypoglycaemia may be
asymptomatic.
Symptoms include diaphoresis, irritability, hypotonia, lethargy, apnea and seizures.

Investigation.

Screening for hypoglycaemia is mandatory for all high-risk infants (EGA <37weeks, Weight <2.5kg, SGA, infants of diabetic mothers, infants of mothers on ß-blockers, infants with cold-stress).
The diagnosis of hypoglycaemia should be confirmed using test strips which are not  affected by haematocrit, oxygen saturation or bilirubin level.
These modern strips usually provide blood glucose values very close to values obtained by spectrophotometery.

Management

Intravenous 10% Dextrose-in-Water
should be administered at the rate of
60ml/kg/day on the first day.
RBG should be checked at 1hour after
commencement of infusion, 6 hourly for
the first 24 hours and thereafter, 12
hourly.
If RBG is < 2.6 mmol/1 and the infant is
asymptomatic, it is important to either
increase the 10% Dextrose-in-Water drip
rate by 50% or increase the concentration of dextrose to 15%.
A central vein should be used to administer dextrose concentration of >12.5%.
Urine should be monitored for glycosuria when high concentration of glucose is infused. As RBG normalizes, the concentration of dextrose infusion should be gradually reduced back to maintenance concentration of either 4.3% or 8%.
Enteral feeding should be continued if the infant can tolerate oral feeding.
If RBG is < 2.6 mmol/1 and drowsiness, seizures or coma are present, bolus of 4ml/kg of 10% dextrose should be  administered and maintenance infusion should be done at the rate of 8 mg/kg/minute.
RBG should be checked after 1 hour. If RBG is >2.6 mmol/l, infusion rate should be reduced to 5mg/kg/minute and RBG should be checked after another 1 hour.
If RBG is <2.6 mmol/l and the infant is asymptomatic, the infusion should be maintained and RBG checked in 3 hours.
However, if RBG is < 2.6 mmol/l and
symptoms persist, the infusion rate
should be increased to 12mg/kg/minute
and RBG should be repeated in 1 hour. If
RBG increases, glucose infusion rate
should be reduced slowly over 4-6 hours.
If hypoglycaemia persists despite
12mg/kg/minute serum insulin should be measured and intravenous hydrocortisone 2.5-5mg/kg should be given 12 hourly.
If this step is ineffective, oral diazoxide 1.7-5 mg/kg 8 hourly with oral chlorthiazide 10mg/kg 12 hourly should be administered with close monitoring for hypotension and dehydration.
In the extreme cases requiring more than 20mg/kg/minute of glucose, subcutaneous somatostatin octreotide lμg /kg 4 hourly or intramuscular glucagon 20µg/kg 6 hourly may be effective.
If hypoglycaemia persists with
hyperinsulinism, partial pancreatectomy
is indicated.