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Neonatal hypoglycaemia
In an at-risk newborn (infant of a diabetic mother, SGA, LGA, late preterm) glucose is checked early and treated against a threshold that rises with the hours; a symptomatic infant, or a low glucose that does not respond to feeding, receives IV glucose, and hypoglycaemia persisting beyond 48 hours needs work-up for hyperinsulinism.
Why it matters in the exam
Glucose falls naturally in the first hours after birth, so the question tests whether the student separates a transitional dip from hypoglycaemia that needs treatment. The typical case is a large infant of a mother with gestational diabetes who is jittery and sweaty at two hours; the answer is an immediate glucose check, and treatment depends on symptoms and the value.
Per AAP 2011, in an asymptomatic at-risk infant: in the first 4 hours a glucose below 25 mg/dL needs a feed and a recheck after one hour, and if it stays below 25 → IV glucose; at 4–24 hours the threshold is 35 mg/dL, and the target before each feed is 45 mg/dL or more. A symptomatic infant with glucose below 40 mg/dL receives IV glucose at once: 2 mL/kg of D10 followed by an infusion at 5–8 mg/kg per minute. Buccal 40% dextrose gel is an option for the asymptomatic infant.
After 48 hours the threshold rises: per PES 2015, aim for glucose above 50 mg/dL, and above 70 mg/dL when a persistent disorder is suspected. A glucose infusion rate above 8 mg/kg per minute, absent ketones and a glycaemic response to glucagon point to hyperinsulinism. A micropenis, midline defects and prolonged jaundice point to hypopituitarism. During hypoglycaemia a "critical sample" is taken.
Key points
- In an at-risk newborn, check glucose early and treat against a threshold that rises with the hours.
- Symptoms and glucose below 40 mg/dL → D10 bolus 2 mL/kg and an infusion.
- After 48 hours the target is above 50 mg/dL.
- A glucose infusion rate above 8 mg/kg per minute with low ketones → hyperinsulinism.
- The critical sample is taken during hypoglycaemia, before correction.
Summary table
| Situation | Threshold or finding | Action | Note |
|---|---|---|---|
| Asymptomatic at-risk infant, 0–4 hours | Glucose below 25 mg/dL | Feed and recheck after one hour; if still low → IV glucose | First check about 30 minutes after the first feed |
| Asymptomatic at-risk infant, 4–24 hours | Glucose below 35 mg/dL | Feed and recheck; if still low → IV glucose | Pre-feed target 45 mg/dL or more |
| Symptomatic infant | Glucose below 40 mg/dL | D10 bolus 2 mL/kg and infusion 5–8 mg/kg per minute | Jitteriness, sweating, apnoea, seizure, poor feeding |
| Hyperinsulinism | Glucose infusion rate above 8 mg/kg per minute, low ketones | Critical sample; diazoxide | Infant of a diabetic mother (transient), Beckwith-Wiedemann, congenital |
| Hypopituitarism | Micropenis, midline defect, prolonged jaundice | Cortisol and GH in the critical sample | Hormone replacement |
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Sources
- AAP Committee on Fetus and Newborn: Postnatal Glucose Homeostasis in Late-Preterm and Term Infants, 2011 (reaffirmed) — Screening and management of at-risk newborns
- Pediatric Endocrine Society: Recommendations for Evaluation and Management of Persistent Hypoglycemia in Neonates, Infants, and Children, 2015 — Thresholds after 48 hours and the critical sample
- Nelson Textbook of Pediatrics, 22nd edition (2024) — Hypoglycemia
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.