Diabetic ketoacidosis in children

Diagnosis & Severity - The Sweet & Sour Test

• Triad: Hyperglycemia + Ketosis + Acidosis
  • Blood Glucose: > 200 mg/dL
  • Venous pH: < 7.3 or HCO₃⁻ < 15 mmol/L
  • Ketones: Present in urine or blood

⭐ In hyperglycemia, measured sodium is falsely low (pseudohyponatremia). Always calculate corrected sodium, a frequent exam topic.

• Corrected Sodium: $Na_{corrected} = Na_{measured} + 1.6 \times \frac{(Glucose_{mg/dL} - 100)}{100}$

Pathophysiology - The Chaos Cascade

• Absolute or relative insulin deficiency, coupled with excess counter-regulatory hormones (glucagon, cortisol), initiates the crisis.
• This dual hormonal imbalance drives two main pathological processes:
  • Hyperglycemia: Leads to glycosuria, osmotic diuresis, profound dehydration, and electrolyte loss.
  • Ketosis: Unrestrained lipolysis releases free fatty acids, which are converted in the liver to ketone bodies (β-hydroxybutyrate & acetoacetate), causing a high anion-gap metabolic acidosis.

⭐ The predominant ketone is β-hydroxybutyrate, but standard urine nitroprusside tests only detect acetoacetate, potentially underestimating the degree of ketosis.

Management: Fluids & Insulin - The Balancing Act

• Initial Resuscitation: Start with 10-20 ml/kg 0.9% Saline bolus over 1-2 hrs. AVOID over-aggressive rehydration.
• Deficit Correction: Replace remaining fluid deficit slowly and evenly over 48 hours using 0.45-0.9% NS.
• Insulin Infusion: Begin 1-2 hours AFTER starting fluids.
  • Dose: 0.05-0.1 units/kg/hr. NO IV insulin bolus.
• Glucose Titration: Add 5% Dextrose to IV fluids when blood glucose falls to ~250-300 mg/dL to prevent hypoglycemia, allowing insulin to continue correcting acidosis.

⭐ To prevent cerebral edema, the rate of blood glucose fall should not exceed 100 mg/dL/hr. Closely monitor neurological status.

Monitoring & Complications - The Brain Watch

• Hourly: Neuro-obs (GCS), vitals, & capillary blood glucose.
• 2-4 Hourly: Venous blood gas & serum electrolytes (esp. K+).
• Strict I/O Charting: Meticulously track fluid balance.

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⚠️ Cerebral Edema

• Highest Risk: 4-12 hours after starting treatment.
• Red Flags: Headache, slowing heart rate, irritability, ↓GCS, incontinence.
• Management Protocol:
  • Elevate head of bed.
  • Reduce IV fluid rate by ⅓.
  • Mannitol: 0.5-1 g/kg IV over 20 min.
  • 3% Hypertonic Saline: 5-10 mL/kg over 30 min.

⭐ For any acute neurological deterioration, presume cerebral edema until proven otherwise. The mortality rate is 20-25%.

High‑Yield Points - ⚡ Biggest Takeaways

• Diagnosis: Blood glucose >200 mg/dL, venous pH <7.3 or HCO3 <15 mmol/L, and ketonemia.
• Initial fluid: 10-20 ml/kg of 0.9% saline. Avoid rapid correction to prevent cerebral edema.
• Insulin: Start 0.1 U/kg/hr infusion after initial fluid resuscitation. No IV bolus.
• Cerebral edema: The most feared complication. Watch for headache, altered sensorium, and bradycardia. Treat with Mannitol.
• Potassium: Add to IV fluids once urine output is confirmed and K+ is <5.5 mEq/L.
• Glucose: Add dextrose to fluids when blood glucose falls to ~250 mg/dL.