Neonatal hypoglycaemia

Question 1

What are normal serum glucose values in the first week of life?

Answer 1

2,5 - 7,5 mmol/l

(levels are variable and fall during the first 24 hours of life

Question 2

• What consideration should you take into account when measuring a baby’s glucose levels with a ward glucometer?
• Why does this phenomenon occur?

Answer 2

• Ward values are approx. 0,5 mmol/l lower than actual serum values (as measured in the lab)
• Neonates have high packed cell volume after birth, which obscures the ward measurement

Question 3

What is the definition of hypoglycaemia in an a neonate?

Answer 3

< 2 mmol/l blood glucose (ward measurement) or < 2,5 mmol/l serum glucose (lab measurement)

Question 4

What is defined as severe hypoglycaemia in the neonate?

Answer 4

Blood glucose < 1,5 mmol/l

Question 5

What are the 4 major mechanisms of hypoglycaemia in a neonate?

Answer 5

1. Decreased glycogen stores
2. Increased glucose demands
3. Increased insulin
4. Liver damage

Question 6

What are the common causes of neonatal hypoglycaemia due to decreased glycogen stores? (4)

Answer 6

1. Preterm infant
2. Underweight for gestational age/wasted infant
3. Post-term infant (especially if wasted)
4. Late feeding or early feeds with water or 5% glucose

Question 7

What are the common causes of neonatal hypoglycaemia due to increased glucose demands? (4)

Answer 7

1. Respiratory distress
2. Hypothermia
3. Infection
4. Polycythaemia

Question 8

What are the common causes of neonatal hypoglycaemia due to increased insulin? (2)

Answer 8

1. Poorly controlled diabetic/IGT mother

2. Severe Rh disease

Question 9

What are the common causes of neonatal hypoglycaemia due to liver damage? (2)

Answer 9

1. Hypoxia

2. Infection

Question 10

What is a rare cause of neonatal hypoglycaemia?

Answer 10

Pancreatic cell hyperplasia

Question 11

What are the clinical presentations of hypoglycaemia in the neonate?

Answer 11

Asymptomatic:

• Picked up on screened tests
• Common in mild hypoglycaemia (although may occur in severe hypoglycaemics)

CNS:
- Floppiness, poor sucking, lethargy, jitteriness, apnoea, cyanosis, convulsions

Cardiac:
- Heart failure, respiratory distress

Question 12

What is a major complication of persistent, symptomatic hypoglycaemia?

Answer 12

Severe brain injury with neurodevelopmental handicap (>30% of cases)

Question 13

Prevention of neonatal hypoglycaemia

Answer 13

• Normal infants breastfed immediately after delivery
• Identify high-risk infants and feed ASAP (can use tube feed if necessary)
• Start IV 10% glucose if milk feeds contraindicated
• Monitor blood glucose every 1-3 hours for first 1-2 days in infants at risk of hypoglycaemia
• Avoid hypothermia

Question 14

Treatment of mild hypoglycaemia

Answer 14

• Give a milk feed (oral glucose never used)
• Keep infant warm
• Repeat blood glucose measurement 30mins after feeding
• If hypoglycaemia persists after feed, repeat feed with milk sweetened with sugar, and re-test glucose in 30 mins
• If reading still abnormal, treat as for severe hypoglycaemia

Question 15

Treatment of severe hypoglycaemia

Answer 15

• Start 10% dextrose (Neonatalyte) IV at 90ml/kg/day
• Measure blood glucose after 15mins. If glucose still low, increased dextrose to 15% (add 10ml 50% glucose to 100ml Neonatalyte) and increase intake to 120ml/kg/day
• 5mg hydrocortisone IV or 0,2mg/kg/dose glucagon IV/IM if glucose therapy alone is insufficient
• Monitor blood glucose carefully and regularly
• Start milk feeds ASAP, sweeten with sugar if needed
• Don’t stop IV glucose until milk feeds are established
• In an emergency, if IV glucose can’t be given (not available, unable to place line), give small feeds of sweetened milk 9never oral glucose)

Question 16

Most likely cause of severe, unresponsive hypoglycaemia?

Answer 16

Hyperinsulinism (mother has uncontrolled diabetes)