Neonatal Hypoglycaemia

Why is this topic important?

Neonatal hypoglycaemia is a common neonatal problem and an important MRCPCH topic because delayed recognition can lead to seizures and neurological injury. Candidates should know risk factors, clinical features and immediate management.

Definition

Neonatal hypoglycaemia refers to a low blood glucose concentration in a newborn infant.

The exact threshold varies between local guidelines, gestation and clinical context. For MRCPCH, the key principle is:

Identify at-risk infants early.
Feed early.
Check blood glucose when indicated.
Treat symptomatic or persistent hypoglycaemia urgently.

Key MRCPCH Facts

Many babies are asymptomatic.
Infants of diabetic mothers are high risk.
Preterm and growth-restricted infants are high risk.
Symptomatic hypoglycaemia is an emergency.
Recurrent or persistent hypoglycaemia needs further investigation.

Pathophysiology

After birth, babies must adapt from continuous placental glucose supply to intermittent feeding.

Hypoglycaemia may occur due to:

Reduced glycogen stores
Increased glucose utilisation
Hyperinsulinism
Poor feeding
Sepsis
Endocrine or metabolic disease

Risk Factors

Maternal

Maternal diabetes
Beta-blocker use
Maternal obesity

Infant

Prematurity
Small for gestational age
Large for gestational age
Intrauterine growth restriction
Hypothermia
Sepsis
Perinatal asphyxia

Clinical Features

May Be Asymptomatic

This is why screening at-risk infants is important.

Symptoms

Jitteriness
Poor feeding
Lethargy
Apnoea
Hypotonia
Temperature instability
Seizures

Investigations

Initial

Blood glucose
Confirm low value using reliable method according to local policy

If Persistent or Severe

Consider:

Blood gas
Ketones
Insulin
Cortisol
Growth hormone
Free fatty acids
Acylcarnitines
Ammonia
Lactate

If Unwell

Septic screen
Blood culture

Management

Asymptomatic At-Risk Infant

Early feeding
Support breastfeeding
Monitor glucose according to local pathway
Buccal glucose gel may be used in many pathways

Symptomatic Hypoglycaemia

Urgent treatment is required.

May include:

IV dextrose
Neonatal unit admission
Close monitoring

Persistent Hypoglycaemia

Consider:

Hyperinsulinism
Endocrine disorder
Metabolic disease

Discuss with senior and specialist teams.

Complications

Short-Term

Seizures
Apnoea
Poor feeding
Temperature instability

Long-Term

Developmental delay
Learning difficulties
Brain injury, especially if severe or prolonged

Common Exam Traps

Trap 1

A baby can be hypoglycaemic without symptoms.

Trap 2

Jitteriness is not always benign; check glucose.

Trap 3

Infants of diabetic mothers are at risk due to hyperinsulinism.

Trap 4

Persistent hypoglycaemia is not just “poor feeding”; consider endocrine/metabolic causes.

One Minute Revision

At risk: IDM, preterm, SGA, LGA, IUGR, sepsis.
Symptoms: jittery, lethargic, poor feeding, seizures.
Check glucose early.
Feed early.
Symptomatic hypoglycaemia needs urgent IV glucose.

Suggested References

BAPM Framework: Identification and Management of Neonatal Hypoglycaemia
NICE Guidance
BNF for Children
Nelson Textbook of Pediatrics
Rennie & Roberton’s Textbook of Neonatology

Disclaimer

These notes are intended for MRCPCH revision and educational purposes only. They do not replace local, national or institutional guidelines. Clinical decisions should always be based on current guidance, senior advice and individual patient circumstances.

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