See also

Diabetes Mellitus

Key points

1. Hypoglycaemia is a Blood Glucose Level (BGL) low enough to cause signs and/or symptoms of impaired brain function and neurogenic response - generally BGL <3.3 mmol/L
2. Infants with BGL <2.6 mmol/L and risk factors are at risk of acute and long-term neurological sequelae.
3. Altered conscious state or seizures warrant prompt BGL assessment and management with a bolus of IV 10% Dextrose (2 mL/kg) or IM glucagon.
4. A venous blood gas and other diagnostic blood tests are important to identify an underlying cause but should not delay management.

Background

• Hypoglycaemia is a BGL low enough to cause signs and/or symptoms of impaired brain function and neurogenic response - generally BGL <3.3 mmol/L
• In neonates <48 hrs old, there is a lack of consensus on what constitutes normal BGL, however, BGL <2.6 warrants immediate intervention
• Prolonged or recurrent hypoglycaemia, especially with clinical features, can cause long term neurological damage or death
• Age at presentation can indicate the underlying case:

** Accelerated starvation is a diagnosis of exclusion.  It requires a history of a prolonged fast (usually precipitated by a mild illness), with low BGL in association with ketonuria and/or ketonaemia and normalisation of BGL upon feeding.

Assessment

Red flag features in Red

History:

• Symptoms of hypoglycaemia
• Palpitations, tremor, anxiety, sweating, hunger, paraesthesia
• Severe hypoglycaemia - lethargy, irritability, uncharacteristic behaviour, hypothermia, confusion, coma, seizures
• Neonate <48 hrs - apnoea, hypotonia, jitteriness, poor feeding, high pitched cry
• Dietary history, fasting/illness and relationship to food
• Milk products (galactosaemia)
• Fructose eg juices (hereditary fructose intolerance)
• Protein (amino acid or organic acid disorders)
• History of toxin ingestion – in toddlers or young children consider accidental ingestion of alcohol, oral hypoglycaemic agents (sulfonylureas), aspirin, beta blockers, or toxins

• Increased glucose requirements, eg sepsis, shock, tumours, trauma
• Past history
• Neonatal history of hypoglycaemia
• Episodes suggestive of hypoglycaemia eg undiagnosed seizure disorder
• Previous gastric surgery, fundoplication (postprandial hypoglycaemia)
• Family history
• Consanguinity
• Unexplained infant deaths (inborn errors of metabolism)
• Hormonal deficiencies and hyperinsulinism

Examination:

• Altered conscious state and seizures
• Fever or hypothermia
• Finding related to underlying diagnosis
• Hepatomegaly and/or hypotonia (inborn error of metabolism)
• Poor growth and nutrition
• Dysmorphic (syndrome)

Management

• First presentation or severe hypoglycaemia should be investigated
• Infants <48 hrs of age who respond appropriately to enteral feeds are unlikely to need extensive investigations
• A capillary glucometer reading is unreliable at low readings; hence it is important to confirm that true (laboratory) BGL is <2.6 mmol/L 

Investigations:

• Venous/capillary blood gas
• Diagnostic blood tests during the period of hypoglycaemia (either at the initial presentation or during an elective fast) prior to management

Minimum blood volume 5 mL
Tubes Required:

1. 3 x 0.5 mL fluoride oxalate
2. 3 x 0.5 mL lithium heparin 
3. 2 x 0.5 mL serum gel tube
4. Newborn Screening Test (Guthrie) card - send air dried and in envelope, not in a plastic specimen bag

All tests must go immediately to the laboratory on an ice pillow

• Urine - first voided urine after hypoglycaemic episode, requesting glucose, ketones, reducing substances and amino and organic acids

Treatment:

• The aim of treatment is to return BGL to within the normal range (>3.9 mmol/L) through normal nutritional intake. See flow chart
• Severe symptomatic hypoglycaemia should be corrected with an IV 10% dextrose bolus 2 mL/kg or IM glucagon (Neonate: glucagon 0.03-0.1 mg/kg, <25 kg give ½ vial (0.5 Units), <25 kg give ½ vial (0.5 Units), >25 kg give full vial (1.0 Units))
• BGL should return to the normal range within 10-15 mins and remain so for 1 hour. Ideally, the child should start to feed and BGL should be rechecked within 30 mins
• Persistent hypoglycaemia - consider consultation with Endocrinology and/or Metabolic specialist

 Discharge requirements

• A cause for hypoglycaemia must be known (or accelerated starvation assumed) prior to discharge
• Neonates: BGL ≥2.6 for 3 consecutive normal feeds
• Infants and older children: BGL >3 mmol/L at least 4 hours post feeds/meals
• Accelerated starvation – parental education regarding prolonged starvation

Consider consultation with local paediatric team when

• Child is not responding to first line treatment of food, IV 10 % Dextrose bolus or IM glucagon
• Neonates

Consider transfer when

• Child requiring multiple Dextrose boluses or Dextrose infusion

• Child requiring care beyond the comfort level of the hospital

For emergency advice and paediatric or neonatal ICU transfers, call the Paediatric Infant Perinatal Emergency Retrieval (PIPER) Service: 1300 137 650.

Parent information sheet

No KHI available - see Diabetic hypoglycaemia

Interpretation of Test results

Last Updated November 2019