Hypoglycemia

Hypoglycemia Basics - Sugar Lowdown

• Definition: Plasma glucose < 45-50 mg/dL (or 2.5-2.8 mmol/L) in neonates, infants, children. Can be symptomatic or asymptomatic.
• Classification:
  • Transient Neonatal: Common; e.g., Intrauterine Growth Retardation (IUGR), Infant of Diabetic Mother (IDM), perinatal stress (asphyxia, sepsis, hypothermia).
  • Persistent: Concerning; e.g., Hyperinsulinemic hypoglycemia (most common cause in infancy), hormonal deficiencies (GH, cortisol, glucagon), Inborn Errors of Metabolism (IEMs), ketotic hypoglycemia (most common cause >1 year).

⭐ Whipple's triad (symptoms of hypoglycemia, low plasma glucose, relief of symptoms after glucose administration) is key for diagnosing symptomatic hypoglycemia.

Causes Unwrapped - The Why Low?

• Hyperinsulinism (↑ Insulin)
  • Congenital Hyperinsulinism (e.g., PHHI)

    ⭐ Persistent Hyperinsulinemic Hypoglycemia of Infancy (PHHI) is the most common cause of recurrent, severe hypoglycemia in neonates and young infants.

  • Infant of Diabetic Mother (IDM) - transient
  • Beckwith-Wiedemann Syndrome
  • Insulinoma (rare in children)
  • Sulfonylurea exposure (accidental)
• Decreased Glucose Production/Substrate (↓ Output)
  • Glycogen Storage Diseases (GSD): Type I, III, VI, IX
  • Fatty Acid Oxidation (FAO) defects
  • Ketotic hypoglycemia (common 1-5 yrs, diagnosis of exclusion)
  • Hormonal: Adrenal insufficiency (cortisol), GH deficiency
  • Prematurity/IUGR (↓ glycogen stores)
  • Severe liver disease
• Increased Glucose Utilization (↑ Demand)
  • Sepsis, severe infections
  • Burns, shock, perinatal asphyxia
  • Large for Gestational Age (LGA) infants (transient fetal hyperinsulinism)
• Drugs/Toxins
  • Insulin, oral hypoglycemics (e.g., sulfonylureas)
  • Beta-blockers (e.g., propranolol)
  • Alcohol, Salicylates (high dose)

Signs & Sleuthing - Spotting the Dip

• Clinical Clues: Vary by age & mechanism.

  • Neonates: Jitteriness, apnea, hypotonia, poor feeding, seizures.
  • Older Children:

    Type	Symptoms
    Neurogenic	Sweating, pallor, tremors, tachycardia, anxiety
    Neuroglycopenic	Lethargy, confusion, seizures, coma, irritability

• Diagnostic Gold: The 'Critical Sample'

  • Collect DURING hypoglycemia (BG <50 mg/dL or <2.8 mmol/L).
  • Key analytes: Glucose, Insulin, C-peptide, GH, Cortisol, Lactate, Ketones (BHOB), FFA.
  • Also: Acylcarnitine profile, urine organic acids/ketones.
  • 

• Interpreting Critical Sample:

• Provocative Tests:

  • Fasting Study: If no spontaneous event; monitor glucose, ketones, insulin.
  • Glucagon Stimulation Test: (e.g., 1mg IM/IV) Glucose rise >25-30 mg/dL suggests adequate glycogen. Blunted in hyperinsulinism.

⭐ In hyperinsulinemic hypoglycemia, ketones are inappropriately low or absent during a hypoglycemic episode.

Fixing the Low - Sweet Solutions

• Acute Management:
  • Prioritize ABCs; secure IV access.
  • Rapid Correction:
    • IV: 2 ml/kg D10W bolus, then Glucose Infusion Rate (GIR) 6-8 mg/kg/min.
      • $GIR (mg/kg/min) = (% Dextrose \times IV rate (ml/hr)) / (6 \times Wt (kg))$
    • No IV access: Glucagon 0.03-0.1 mg/kg IM/SC/IV (max 1mg).
    • Conscious & cooperative: Oral glucose (juice, gel).
• Long-term Management (Etiology-Specific):
  • Hyperinsulinism: Diazoxide, Octreotide, Nifedipine; surgery if refractory.
  • Glycogen Storage Diseases (GSD): Regular uncooked cornstarch.
  • Hormonal Deficiencies (GH, Cortisol): Specific hormone replacement.
  • Ketotic Hypoglycemia: Frequent small high-carb/protein feeds; bedtime cornstarch.
• Monitoring & Prevention: Regular glucose monitoring; educate on signs, prevent recurrence.

⭐ The 'Rule of 50' for initial correction in neonates: 2 ml/kg of D10W (10% Dextrose in Water) provides 200 mg/kg of glucose.

High‑Yield Points - ⚡ Biggest Takeaways

• Neonatal hypoglycemia: Blood glucose < 45 mg/dL; common in IDM, prematurity, IUGR, sepsis.
• Whipple's Triad: Symptoms, low glucose, relief with glucose administration.
• PHHI (Congenital Hyperinsulinism): Most common cause of persistent hypoglycemia in infants.
• Ketotic Hypoglycemia: Most common in toddlers (18 months-5 years), triggered by fasting/illness.
• Critical Samples: Collect before glucose for insulin, C-peptide, GH, cortisol, ketones.
• Management: Oral glucose if conscious; IV Dextrose if severe; Glucagon for emergency_.