What is the initial treatment for a 20-month-old boy with severe DKA and metabolic acidosis?

Initial Treatment for Pediatric DKA with Venous pH 7.15

The initial treatment for a 20-month-old boy with DKA (venous pH 7.15) should begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour for fluid resuscitation, followed by insulin therapy only after fluid resuscitation has begun and potassium levels are confirmed to be ≥3.3 mEq/L. 1

Initial Assessment and Fluid Resuscitation

1. Immediate fluid replacement:

   • Begin with 0.9% NaCl at 15-20 mL/kg/hour initially 1
   • Aim to correct estimated fluid deficits within 24 hours
   • Goal: expand intravascular volume, improve tissue perfusion and renal function

2. Laboratory assessment (obtain immediately):

   • Complete blood count, electrolytes, BUN, creatinine
   • Arterial blood gases
   • Serum ketones (β-hydroxybutyrate preferred)
   • Urinalysis 1

3. Ongoing fluid management:

   • After initial resuscitation, adjust fluid rate based on:
     • Hydration status
     • Serum electrolytes
     • Urine output
   • If corrected sodium is normal/elevated, switch to 0.45% NaCl at 4-14 mL/kg/hour
   • If corrected sodium is low, continue 0.9% NaCl 1

Electrolyte Replacement

1. Potassium replacement:

   • Start when serum K+ <5.5 mEq/L and adequate urine output is confirmed
   • Add 20-40 mEq/L of potassium to each liter of IV fluid
   • Use combination of KCl (2/3) and KPO₄ (1/3) 1
   • Critical safety point: Ensure potassium level is ≥3.3 mEq/L before starting insulin

2. Monitor other electrolytes:

   • Phosphate replacement if serum phosphate <1.0 mg/dL
   • Monitor sodium, correcting for hyperglycemia (for each 100 mg/dL glucose >100, add 1.6 mEq to measured sodium) 2

Insulin Therapy

1. Timing: Start insulin 1-2 hours after beginning fluid resuscitation 1

2. Administration:

   • No initial insulin bolus in pediatric patients 2
   • Begin continuous IV insulin infusion at 0.1 units/kg/hour 2, 1
   • Start only when serum potassium is ≥3.3 mEq/L 1

3. Monitoring and adjustment:

   • Target glucose reduction: 50-75 mg/dL per hour
   • If glucose doesn't decrease by ≥50 mg/dL in first hour:
     • Check hydration status
     • If adequate, double insulin infusion rate hourly until achieving stable decline 1
   • When glucose approaches 250 mg/dL, add dextrose to IV fluids to prevent hypoglycemia 1

Ongoing Monitoring

1. Frequent assessment:

   • Vital signs, mental status, urine output every 1-2 hours
   • Electrolytes, glucose, venous pH every 2-4 hours 2
   • Monitor for signs of cerebral edema (headache, altered mental status, bradycardia, hypertension)

2. Resolution criteria:

   • Blood glucose <200 mg/dL
   • Venous pH >7.3
   • Bicarbonate ≥18 mEq/L
   • Normalized anion gap 1

Special Considerations for This Case

1. Cerebral edema risk:

   • Particularly high in young children
   • Avoid excessive fluid administration
   • Avoid rapid changes in serum glucose and osmolality 1

2. Cachexia and lethargy:

   • May indicate severe dehydration and prolonged DKA
   • Consider more cautious fluid resuscitation if signs of cardiac compromise
   • Monitor closely for electrolyte abnormalities

3. ICU admission:

   • Given the patient's age (20 months), lethargy, and severe acidosis (pH 7.15), ICU admission is warranted for close monitoring 2

Common Pitfalls to Avoid

1. Administering insulin bolus in pediatric patients (increases risk of cerebral edema) 2

2. Starting insulin before adequate fluid resuscitation or before confirming potassium ≥3.3 mEq/L 1

3. Excessive fluid administration, which can contribute to cerebral edema, especially in young children 1

4. Failure to monitor for cerebral edema, the most dangerous complication of pediatric DKA 3

5. Inadequate potassium replacement, which can lead to potentially fatal arrhythmias 1