Hypoglycaemia in neonates

Follow these guidelines when investigating neonatal hypoglycaemia:

• Reagent sticks used for screening may overestimate the occurrence of hypoglycaemia.
• Confirm suspected hypoglycaemia with true blood glucose estimation on at least one occasion and this should be processed urgently.
• The infant of an insulin requiring diabetic mother and those admitted to intensive or special care nursery should have screening performed promptly after arrival in the nursery.
• Screening should be performed in the postnatal ward if the infant is at low risk (for example, normosomic infant of non-insulin requiring diabetic mother or the mildly growth restricted term infant with birth weight > 2 kg).
• Premature infants who can be fed early after birth (appropriate for gestational age infants > 34 weeks gestation) will generally only require screening before the first two three-hourly feeds.

Congenital adrenal hyperplasia

Issues to note for infants with congenital adrenal hyperplasia:

• Infants with CAH which may be associated with ambiguous genitalia can present with hypoglycaemia.
• Failure to investigate and promptly treat these cases of ambiguous genitalia can be disastrous.

Hyperinsulinism

Infants with a steady supply of glucose and intact counter regulatory hormonal pathways should remain normoglycaemic when receiving 4-8 mg/kg/min of glucose.

If an infant requires > 10 mg/kg/min of IV glucose to maintain normoglycaemia then hyperinsulinism is suspected. This requires further investigation to confirm diagnosis. The following blood tests should be collected when the true blood glucose is < 2.0 mmol/L:

• glucose
• insulin
• growth hormone
• cortisol
• free fatty acids. 

Urine should be tested for ketones.

A helpful calculation for mg/kg/min of IV glucose

A helpful calculation for mg/kg/min of IV glucose is to convert the % dextrose/10 x mL/kg/day x 0.07 to obtain mg/kg/min.

For example

• 10 per cent dextrose at 60 mL/kg/day will give 4.2 mg/kg/min (10/10 x 60 x 0.07)
• 12.5 per cent dextrose at 100 mL/kg/day will give 8.75 mg/kg/min (12.5/10 x 100 x 0.07).

Screening for hypoglycaemia

Postnatal ward (PNW) management

Special care nursery (SCN) management

Prevention of hypoglycaemia

The following strategies will assist prevention of hypoglycaemia:

• mothers of at risk infants may be advised regarding antenatal expression of breast milk
• promote early prolonged skin to skin contact and breastfeeding
• prevent hypothermia
• if able to take enteral feeds commence by one to two hours of age
• feed frequently either two-hourly or three-hourly if risk is low
• use expressed breast milk or full strength formula at 60 mL/kg initially, increasing to 90 mL/kg by 24 hours according to tolerance
• if the infant is nil by mouth then commence IV 10 per cent glucose at 60-90 mL/kg/24 hours (4-6 mg/kg/min of glucose)
• if fluid restriction is required increase the concentration of glucose in the infusion.

Oral feeds

If a hypoglycaemic infant is able to tolerate enteral feeding, this should be given.

Description

Glucose is a simple monosaccharide, which is a source of energy for the body. The glucose gel is used to increase blood glucose levels for the treatment of neonatal hypoglycaemia.

Preparation

Oral gel, 15 g glucose in 37.5 g (d-glucose/dextrose USP 40%)

Dose

Buccal: 0.5 mL/kg
Postnatal ward: Maximum 6 doses in first 48 hours (refer PNW flow chart)

Administration

• Dry inside of baby's mouth.
• Twist tip of tube off and squeeze contents into measuring cup to withdraw dose. Tube may be used by same baby until discharged or contents expire (if prior to discharge).
• Label tube with baby's identification sticker.
• Measure required dose of glucose gel with dispenser.
• Apply small amounts gel at a time to buccal mucosa and massage gently with a clean, gloved finger.
• Do not put gel to back of mouth.
• Document administration on the medication chart. Two doses may be initiated in the 'once only medicines' by a registered nurse/midwife thereafter ordered by a medical officer (up to six doses in first 48 hours after birth) or ordered as per hospital policy.
• Continue to monitor BGL as per appropriate flow chart.

Side effects

• Gagging
• Vomiting
• Hyperglycaemia

Contraindication

• Hypersensitivity to gel

Follow these guidelines if the infant is unable to tolerate enteral feeds or if there is no response to the feed:

• Give an IV bolus of 200-300 mg/kg glucose (2-3 mL/kg of 10% glucose).
• This is followed by a continuous IV infusion of 10 per cent glucose at 60-80 mL/kg/day (4.2-5.6 mg/kg/min glucose) to prevent rebound hypoglycaemia.
• If fluid restriction is necessary, give more concentrated glucose solution.
• IV infusion of solutions with > 12.5 per cent glucose are best given through an umbilical venous catheter or  central line in order to avoid complications. (However, inability to gain such access should not preclude using such higher concentrations of glucose.)
• Once the blood glucose normalises, enteral feeds can be reintroduced and the infusion weaned off.
• If the infusion is no longer required, the otherwise well infant could have their blood glucose measurements taken in the postnatal ward if it is otherwise safe to do so.

Prescriptions for IV glucose
Prescription to make up a 50 mL solution of various glucose infusions are listed below:

Guidelines for neonatal management with glucagon:

• In infants with adequate glycogen stores (eg. hyperinsulinaemic states) whose hypoglycaemia persists in spite of an IV infusion, administer an IM stat injection of glucagon 0.03 to 0.1 mg/kg. This may be repeated after 6-12 hours. Some infants of diabetic mothers may require up to 0.3 mg/kg to a maximum dose of 1 mg (total dose, not per kg).
• If hypoglycaemia recurs or persists despite IV infusion of 12.5% glucose at 120ml/kg/d (10.5mg/kg/min glucose), an IV glucagon infusion should be considered (1-20 micrograms/kg/hr) while arrangements are made to transfer the infant to a Tertiary centre for continued treatment.

Other treatments to consider for neonatal hypoglycaemia include:

• Corticosteroids (for example, hydrocortisone, 5-10 mg/kg/24hours IM/IV) are used rarely in severe hypoglycaemia to raise blood glucose levels.

The cause of hypoglycaemia (for example, hypothermia, sepsis) must also be treated.

There should be a discussion with PIPER if an infant is requiring more than 100 mL/kg/day of > 12.5 per cent glucose (8.75 mg/kg/min).

See the glucose delivery calculator

• Williams AF. Neonatal Hypoglycaemia: Clinical and legal aspects Seminars in Fetal & Neonatal Medicine 2005; 10: 363-368
• Koh THHG, Aynsley-Green A, Tarbit M, Eyre JA. Neural dysfunction during hypoglycaemia. Arch Dis Child 1988;63:1353-1358.
• Lucas A, Morley R, Cole TJ. Adverse neurodevelopmental outcome of moderate neonatal hypoglycaemia. Br Med J 1988;297:1304-1308.
• Boardman, J.P., Wusthoff, C.J. & Cowan, F.M., Hypoglycaemia and neonatal Brain Injury. Arch Dis Child 2013;98:2-6
• Queensland Clinical Guidelines: Newborn hypoglycaemia at www.health.qld.gov.au updated August 2013
• The Women’s Hospital Clinical Practice Guidelines: Hypoglycaemia: Infant Management at www.thewomens.org.au updated October 2013
• Royal Children’s Hospital Clinical Practice Guideline(Nursing): Neonatal Hypoglycaemia at www.rch.org.au updated December 2012

Other reading

• Hawdon JM, Aynsley-Green A. Metabolic disease. In: Rennie JM, Roberton NRC (eds). Textbook of Neonatology, 3rd edition. Churchill Livingstone, London, 1999, pg. 939-956.
• Cornblath M. Hypoglycaemia. In: Proceedings of Special Ross Conference, Hot Topics in Neonatology, Washington DC, 2000.
• Harris DL, Weston PJ, Signal M, Chase G, Harding JE. Dextrose gel for neonatal hypoglycaemia (the Sugar Babies Study): a randomised, double-blind, placebo-controlled trial. Lancet 2013;382(9910):2077-83. Epub 2013 Sep 25