Definition
- Hypoglycaemia: Blood glucose (BGL) ≤ 2.8 mmol/L
Treat if:
- BGL ≤ 4.0 mmol/L with symptoms
- BGL ≤ 2.8 mmol/L, regardless of symptoms
Common Causes
- Ketotic Hypoglycaemia (fasting ± intercurrent illness)
- Exogenous Insulin or Medication Use
- Endocrine/Metabolic Disorders (GH deficiency, adrenal insufficiency, GSD, FAOD, etc.)
Assessment/Investigations
Step 1: POC Glucose
- If BGL < 2.8 mmol/L, move to a monitored area
Step 2: POC Ketones (β-Hydroxybutyrate, BOHB)
- BOHB ≥ 1.8 mmol/L → Likely Ketotic Hypoglycaemia
- BOHB < 1.8 mmol/L → Further investigation required
Step 3: Assess Fasting Duration
Fasting duration should be long enough to explain hypoglycaemia:
- <1 year: >15 hours
- 1-5 years: >24 hours
- >5 years: >24-36 hrs
Step 4: Identify Red Flags
Children with recurrent episodes, inadequate fasting history, or red flags require investigation.
Red Flags for Pathological Hypoglycaemia:
- Abnormal growth (short stature, failure to thrive)
- Hyperpigmentation (adrenal insufficiency)
- Hepatomegaly (glycogen storage disorders, metabolic conditions)
- Developmental delay
- Midline defects (pituitary insufficiency)
Management Approach
1. First-time Ketotic Hypoglycaemia
BOHB ≥ 1.8 mmol/L + adequate fasting duration + normal exam:
- No critical sample needed
- Treat with oral carbohydrates (if tolerated) or IV dextrose
- Safe discharge if tolerating fluids, improving clinically
2. Suspected Pathological Hypoglycaemia
BOHB < 1.8 mmol/L OR inadequate fasting OR abnormal exam OR recurrent episodes:
- Take Critical Sample BEFORE dextrose if possible
- Critical Sample Includes:
- Plasma glucose (lab confirmation of hypoglycaemia)
- BOHB (assess ketosis)
- Insulin & C-peptide (insulin excess)
- Cortisol & GH (endocrine causes)
- Venous gas (acidosis → GSD/mitochondrial disease)
- Acylcarnitine, amino acids, urine organic acids (metabolic disorders)
Treat with IV dextrose immediately if unstable
Key Considerations
- Do NOT delay treatment if critically unwell
- All POC glucose readings <2.8 mmol/L require lab confirmation
- Recurrent episodes → Consider fasting study & endocrine/metabolic referral
Links
- IAEM national Clinical guideline: Paediatric Hypoglycaemia. October, 2024. Dr Seán Underwood, Dr Emmanuelle Fauteux-Lamarre