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Key points

• Hypoglycaemia is defined as a blood glucose level (BGL) of ≤2.6 mmol/L using a blood gas machine, iSTAT, or formal laboratory testing.
• Ketotic hypoglycaemia (KH) of childhood is the most common cause of hypoglycaemia in children.
• In the absence of a history of prolonged fasting (over 30 hours) and blood ketones >4, all children with a formal BGL ≤2.6mmol/L should be investigated for an underlying disorder.
• Management of hypoglycaemia includes administration of a Glucose 10% bolus followed by a Glucose 10% + Sodium Chloride 0.9% IV infusion (which needs to be mixed onsite).
• Fluids containing less than Glucose 10% (such as Glucose 5% + Sodium Chloride 0.9%) are unsuitable.
• Hypoglycaemia is a medical emergency. If left untreated it can cause convulsions, irreversible brain damage and death.

Purpose

This document provides clinical guidance for all staff involved in the care and management of a child presenting to an Emergency Department (ED) in Queensland with unexplained hypoglycaemia.

This guideline has been developed by the department of Metabolic Medicine at the Queensland Children’s Hospital in consultation with senior ED clinicians and Paediatricians across Queensland. It has been endorsed for statewide use by the Queensland Emergency Care of Children Working Group in partnership with the Queensland Emergency Department Strategic Advisory Panel and the Healthcare Improvement Unit, Clinical Excellence Queensland.

Introduction

Maintaining glucose homeostasis relies on:

• an intact system of endocrine hormones (insulin, glucagon, growth hormone, cortisol)
• a system of intact metabolic pathways to be able to use fat, protein and glucose
• suitable substrates that are able to be metabolised to produce glucose/ketones for energy in times of fasting e.g. glycogen, protein, fat.

Some children become symptomatic of hypoglycaemia or hypoglycaemic faster than others.

The most common cause of hypoglycaemia in children is ketotic hypoglycaemia (KH) of childhood. This is a physiological condition that is a variant of normal and expected in a fasting state. Most children grow out of KH by mid-late primary school age.

Refer to the Queensland Newborn Hypoglycaemia Guideline [PDF] for the management of newborns prior to initial discharge from hospital. The management of children with a diagnosis known to present with hypoglycaemia is beyond the scope of this guideline. Manage these children as per their emergency sick day management plan.

Assessment

A child with hypoglycaemia may appear drowsy, listless and lethargic.

A thorough history and examination is important to identify other precipitating causes that need further investigation.

History

History taking should include the following:

• How long has the child fasted before becoming hypoglycaemic?
• Has the child suffered symptoms of vomiting, diarrhoea or fasted in the last three days?
• Is the child sometimes difficult to wake in the morning?
• How long does the child usually fast overnight?
• Was the hypoglycaemia precipitated by a protein meal?
• Has the child had recent exposure to fruit or honey (consider hereditary fructose intolerance)?
• Could the child have had any medications or alcohol? (especially insulin, metformin, beta-blockers, quinine, chloroquine, salicylates and valproate)

Examination

Seek senior emergency/paediatric advice as per local practice if suspect an underlying disorder.

Investigations

The presence of blood or urinary ketones at the time of presentation is essential to differentiating possible causes of the hypoglycaemia and obtaining a final diagnosis. Blood ketones can be rapidly performed in ED and should be measured at the same time as formal confirmation of blood glucose. If testing urinary ketones, it is important to obtain the first urine passed after the hypoglycaemia is confirmed.

Blood collection

Ideal blood collection for the initial investigation of unexplained hypoglycaemia

Preferred blood collection (volume 5mL)

Tube type	Tube description		Volume required	Tests required
Serum	Red or yellow pedi-pot		3mL	free fatty acids βhydroxybutyrate cortisol growth hormone insulin E/LFTs
Lithium heparin no gel	Green pedi-pot or adult pot		0.5mL	acylcarnitine plasma amino acids
Fluoro-oxalate	Grey pedi-pot		1mL	glucose lactate Can be performed on VBG
EDTA	Purple pedi-pot		0.5mL	ammonium Notify and send to lab urgently. Check with lab if needs to be on ice.

Prioritised blood collection for child with blood collection difficulties

Urine

A urine metabolic screen includes urine amino acids and organic acids.

Management

Refer to flowchart [PDF 362 KB] for a summary of the management of a child presenting to ED with hypoglycaemia.

Acute management

Obtain IV/IO access rapidly for child with BGL <3.0 mmol/L on a glucometer.

Upon obtaining IV access:

• obtain formal BGL on blood gas machine, iSTAT or formal laboratory testing
• draw 5 mL of blood (ideally) for further investigations (See Investigations section)
• measure blood ketones using a blood ketone monitor

Management of child with formal BGL >2.6 mmol/L

• If low normal BGL, push fluids with initial high sugar content (apple juice, flavoured ice block) followed by more complex carbohydrates.
• If formal BGL is greater than 3.0mmol/L, do not send bloods for further investigation

Management of child with hypoglycaemia (formal BGL ≤2.6mmol/L)

Children with a history of prolonged fasting (over 30 hours) and blood ketones >4 can be managed as KH.

In addition to treating the hypoglycaemia, blood and urine should be collected from all remaining children to screen for an underlying disorder (refer to Investigation section).

IM glucagon is unlikely to benefit a child with KH.

IO route is recommended if unable to obtain IV access.

Consider seeking senior emergency/paediatric advice as per local practice for child with a BGL ≤2.6, a history of fasting over 30 hours and blood ketones >4.

Seek senior emergency/paediatric advice as per local practice for child BGL ≤2.6 without a history of fasting over 30 hours and blood ketones >4. Additional investigations are required.

Ongoing management

Seek senior emergency/paediatric advice as per local practice if no clinical improvement following initial glucose bolus and IV fluid infusion.  Consider seeking paediatric metabolic advice.

Seek relevant specialist advice as clinically indicated by results of the hypoglycaemia screen for ongoing investigations and management.

Review the IV fluid calculation and glucose concentration for children with ongoing symptoms of clinical concern following initial bolus and IV infusion. Consider alternate/concurrent diagnoses.

On admission to the ward or SSU:

• continue 10% glucose + 0.9% NaCl at maintenance rate (plus additional fluids to replace deficit if dehydrated).
• administer Ondansetron for children over 12 months of age with nausea or vomiting (note ketones alone can cause nausea which may not settle until ketones have cleared).
• encourage oral fluids (see below) and diet, preferably with foods containing carbohydrates.
• once tolerating oral intake IV fluids may be discontinued or changed to 5% glucose with 0.9% NaCl at a reduced rate.
• organise discharge medications (glucose gel and glucose 10% polymer, +/- ondansetron) early in admission.

Monitoring

Children with hypoglycaemia require routine observation as dictated by their clinical condition.

BGL monitoring

Consider BGL monitoring for the following children:

• symptoms of clinical concern such as pallor, vomiting, tachycardia or drowsiness
• ketones that are absent or inappropriately low (consider hyperinsulinism and continue BGL monitoring until insulin level is known).

It is the treating doctor’s responsibility to document if BGL monitoring is required.

Ketone monitoring

Test urine for ketones after 12 – 24 hours of treatment to ensure urine ketones have cleared or are clearing. If ketones are present, continue to monitor 12 – 24-hourly until cleared.

Escalation and advice outside of ED

Clinicians can contact the services below if escalation of care outside of senior clinicians within the ED is needed, as per local practices. Transfer is recommended if the child requires a higher level of care.

Inter-hospital transfers

Disposition

All patients with unexplained hypoglycaemia require a period of observation. Admission to an inpatient service is usually required but admission to an SSU (where relevant) may be considered.

Children with refactory BGLs despite IV therapy or rebound hypoglycaemia on cessation of fluids require admission to an inpatient service.

Discharge from the ward or SSU

On discharge, caregiver/s should be provided with:

• script for the following:
  • 1 tube of glucose gel
  • +/- Ondansetron
  • +/- 1 can of 10% glucose polymer with the age-appropriate recipe (Lucozade is an appropriate alternative if more than 5 years of age)
• education including:
  • signs, symptoms and emergency management of hypoglycaemia
  • written instructions on management to prevent a recurrent hypoglycaemic episode as per Sick Day Plan [PDF 480.13 KB]
  • advice against purchasing a glucometer or monitoring BGLs at home (as results can be inaccurate and misleading)

Follow-up

In the event that an overnight fast rather than an intercurrent vomiting illness precipitated the hypoglycaemic episode, discuss with the on-call Metabolic Physician, Queensland Children’s Hospital. The administration of night time cornstarch may be required on discharge.

First presentation of unexplained hypoglycaemia

• formal written referral to the Department of Metabolic Medicine, Queensland Children’s Hospital to review results of initial metabolic screening. Consultation can be conducted via telehealth if required.

Subsequent presentations

• liaise with Department of Metabolic Medicine, Queensland Children’s Hospital to determine the need for further outpatient follow-up and if needed book into local General Paediatric outpatient clinic.

Related documents

• Sick Day Plan [PDF 480.13 KB]