What is the initial management for a 13-year-old patient weighing 40 kgs with diabetic ketoacidosis (DKA) and altered mental status?

Initial Management of DKA with Altered Mental Status in a 13-Year-Old (40 kg)

For a critically ill 13-year-old with DKA and altered mental status, begin immediate isotonic saline resuscitation at 15-20 mL/kg/hour (600-800 mL/hour for this 40 kg patient) while holding insulin until potassium is confirmed ≥3.3 mEq/L, then start continuous IV regular insulin at 0.1 units/kg/hour (4 units/hour). 1

Immediate Assessment and Stabilization

Critical Laboratory Evaluation

• Obtain plasma glucose, arterial blood gases, serum ketones, complete metabolic panel with calculated anion gap, serum osmolality, urinalysis with ketones, complete blood count, and electrocardiogram 1
• Check potassium level immediately before any insulin administration - this is the absolute priority as insulin will drive potassium intracellularly and can precipitate fatal arrhythmias 1, 2
• Obtain bacterial cultures (blood, urine, throat) given altered mental status, as infection is a common precipitant 1

Fluid Resuscitation Protocol

• Start with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour - for this 40 kg patient, infuse 600-800 mL in the first hour 1
• This aggressive initial fluid replacement restores tissue perfusion and improves insulin sensitivity 1
• Total fluid replacement should correct estimated deficits within 24 hours 1
• When serum glucose reaches 250 mg/dL, switch to 5% dextrose with 0.45-0.75% NaCl to prevent hypoglycemia while continuing insulin therapy 1

Insulin Therapy

Critical Potassium Threshold

• Do NOT start insulin if potassium <3.3 mEq/L - this is an absolute contraindication 1, 3
• If K+ <3.3 mEq/L: delay insulin, continue isotonic saline, and aggressively replace potassium with 20-40 mEq/L in IV fluids until K+ ≥3.3 mEq/L 3
• Obtain ECG to assess cardiac effects of hypokalemia 3

Insulin Infusion Protocol

• Once K+ ≥3.3 mEq/L, start continuous IV regular insulin at 0.1 units/kg/hour (4 units/hour for 40 kg patient) 1, 3
• For critically ill patients with altered mental status, continuous IV insulin is the standard of care - subcutaneous insulin is NOT appropriate 1
• Target glucose decline of 50-75 mg/dL per hour 1, 3
• If glucose does not fall by 50 mg/dL in the first hour, verify adequate hydration, then double the insulin infusion rate hourly until achieving steady decline 1
• Continue insulin infusion until complete DKA resolution regardless of glucose levels - do not stop when glucose normalizes 1

Electrolyte Management

Potassium Replacement

• Once K+ is 3.3-5.5 mEq/L and urine output is adequate, add 20-30 mEq/L potassium to IV fluids (use 2/3 KCl and 1/3 KPO₄) 1, 3
• Target serum potassium 4-5 mEq/L throughout treatment 1
• Monitor potassium every 2-4 hours - total body potassium depletion averages 3-5 mEq/kg (120-200 mEq for this patient), and insulin will unmask this depletion 1
• If K+ >5.5 mEq/L initially, withhold potassium but monitor closely as levels will drop rapidly with insulin 1

Bicarbonate Administration

• Do NOT administer bicarbonate for pH >6.9-7.0 - multiple studies show no benefit and potential harm including worsening ketosis, hypokalemia, and increased cerebral edema risk 1
• This is particularly critical in pediatric patients who have higher cerebral edema risk 1

Monitoring Protocol

Frequent Biochemical Assessment

• Check blood glucose every 1-2 hours initially 2
• Draw serum electrolytes, glucose, BUN, creatinine, osmolality, and venous pH every 2-4 hours 1
• Monitor venous pH and anion gap to track acidosis resolution - venous pH is typically 0.03 units lower than arterial pH 1
• Direct measurement of β-hydroxybutyrate is preferred for ketone monitoring 1, 3

DKA Resolution Criteria

DKA is resolved when ALL of the following are met 1, 3:

• Glucose <200 mg/dL
• Serum bicarbonate ≥18 mEq/L
• Venous pH >7.3
• Anion gap ≤12 mEq/L

Special Considerations for Altered Mental Status

Cerebral Edema Risk

• Altered mental status in pediatric DKA raises concern for cerebral edema, which occurs more commonly in children and adolescents than adults 1
• Avoid overly rapid correction of osmolality - this increases cerebral edema risk 1, 4
• Monitor closely for worsening mental status, headache, or neurological deterioration 1
• The goal is gradual correction: target glucose 150-200 mg/dL until DKA resolution, not rapid normalization 1

Common Pitfalls to Avoid

• Never stop insulin infusion when glucose falls to 250 mg/dL - this is a common error causing persistent ketoacidosis; instead add dextrose and continue insulin 1
• Never start insulin before confirming K+ ≥3.3 mEq/L - this can cause fatal arrhythmias 1, 3
• Never use correction-only (sliding scale) insulin without basal coverage - this leads to worse outcomes 2
• Failure to add dextrose when glucose <250 mg/dL while continuing insulin therapy 1

Transition Planning

When DKA Resolves

• Administer basal insulin (glargine or detemir) subcutaneously 2-4 hours BEFORE stopping IV insulin to prevent rebound hyperglycemia and recurrent DKA 1, 3
• For this 40 kg patient, start basal insulin at approximately 0.5 units/kg/day = 20 units once daily 2
• Start multiple-dose regimen with combination of rapid-acting and long-acting insulin once patient can eat 1, 3
• Continue IV insulin for 1-2 hours after administering subcutaneous insulin 3