Residency · Residency · Medicine Pediatrics

Diabetic Ketoacidosis: Pediatric Protocols vs. Adult Protocols

Introduction

Diabetic ketoacidosis (DKA) is an acute, life-threatening complication of diabetes mellitus characterized by hyperglycemia, metabolic acidosis, and ketonemia. While the biochemical derangement is similar across ages, management protocols differ substantially between pediatric and adult patients, particularly regarding fluid resuscitation rates and the risk of cerebral edema in children.

Definition and Diagnostic Criteria

DKA Criteria

Blood glucose >200 mg/dL (often >300 mg/dL in adults; may be lower in pediatric patients on insulin) Venous pH <7.3 or serum bicarbonate <18 mEq/L. Ketonemia (beta-hydroxybutyrate >3 mmol/L) or ketonuria.

Severity Classification

Pathophysiology

Insulin deficiency (absolute in Type 1; relative in Type 2) combined with counter-regulatory hormone excess. Unopposed glucagon, cortisol, catecholamines, and growth hormone drive: Hepatic gluconeogenesis and glycogenolysis (hyperglycemia) Lipolysis and ketogenesis (ketonemia and acidosis) Osmotic diuresis (dehydration and electrolyte losses) Total body potassium is depleted despite initially normal or elevated serum potassium.

Epidemiology and Precipitants

Pediatric

DKA is the presenting diagnosis in 30-40% of new-onset Type 1 diabetes in children. Precipitants: New diagnosis, insulin omission (especially in adolescents), illness, pump failure. Younger children (<5 years) are at highest risk for misdiagnosis and severe DKA.

Adult

More commonly occurs in known diabetics. Precipitants: Infection (most common), medication non-adherence, new-onset diabetes, myocardial infarction, substance use. Euglycemic DKA: Increasingly recognized with SGLT2 inhibitor use (glucose may be <250 mg/dL)

Pediatric DKA Management (ISPAD/AAP Guidelines)

Fluid Resuscitation

Initial bolus: 10-20 mL/kg 0.9% NaCl over 1-2 hours (only if hemodynamically compromised) Maintenance + deficit replacement: Correct estimated deficit (typically 5-10%) evenly over 24-48 hours. Use isotonic fluids initially; transition to 0.45-0.9% NaCl with dextrose once glucose <300 mg/dL. Avoid rapid fluid administration due to cerebral edema risk.

Insulin

Continuous IV insulin infusion: 0.05-0.1 units/kg/hour (no initial bolus) Do not start insulin until potassium is confirmed 3.5 mEq/L or above. Target glucose decline of 50-100 mg/dL per hour. Add dextrose to fluids when glucose approaches 300 mg/dL to allow continued insulin infusion.

Potassium Replacement

Begin potassium replacement with initial fluids if serum K+ <5.5 mEq/L. 20-40 mEq/L in maintenance fluids (KCl and KPO4 combination) Monitor serum potassium every 1-2 hours initially.

Bicarbonate

Generally NOT recommended in pediatric DKA. Consider only if pH <6.9 with hemodynamic compromise.

Adult DKA Management (ADA Guidelines)

Fluid Resuscitation

Initial bolus: 1-1.5 L (15-20 mL/kg) 0.9% NaCl in the first hour. Subsequent fluids: 250-500 mL/hour of 0.45% or 0.9% NaCl depending on sodium. More aggressive fluid resuscitation than pediatric protocols. Add D5 to fluids when glucose <200 mg/dL.

Insulin

Continuous IV insulin infusion: 0.14 units/kg/hour OR 0.1 units/kg/hour after 0.1 units/kg bolus. Target glucose decline of 50-75 mg/dL per hour. Transition to subcutaneous insulin when: pH >7.3, bicarbonate >15, glucose <200, patient is eating. Overlap IV and subcutaneous insulin by 1-2 hours to prevent rebound DKA.

Potassium Replacement

If K+ <3.3: Hold insulin, replace potassium aggressively (20-40 mEq/hour) If K+ 3.3-5.3: Add 20-30 mEq/L to each liter of IV fluid. If K+ >5.3: Hold potassium, recheck in 2 hours.

Bicarbonate

Consider if pH <6.9 (100 mmol NaHCO3 in 400 mL water with 20 mEq KCl over 2 hours)

Cerebral Edema

Epidemiology

Occurs in 0.5-1% of pediatric DKA episodes; mortality 20-25%. Extremely rare in adult DKA. Risk factors: Younger age, new diagnosis, longer duration of symptoms, higher BUN, lower pCO2.

Clinical Signs

Headache, vomiting, altered mental status after initial improvement. Cushing triad (hypertension, bradycardia, irregular respirations) Pupillary changes, posturing.

Management

Hypertonic saline (3%) 2.5-5 mL/kg over 10-15 minutes OR mannitol 0.5-1 g/kg IV. Reduce IV fluid rate; Elevate head of bed; Emergent neuroimaging once stabilized; Intubation may be necessary but avoid hyperventilation.

Monitoring

Hourly: Blood glucose, vital signs, neurologic checks (pediatric) Every 2-4 hours: BMP (Na, K, Cl, HCO3, BUN, Cr), venous blood gas, beta-hydroxybutyrate. Corrected sodium: Should rise as glucose falls; failure to rise suggests excess free water. Anion gap: Track closure as marker of resolution.

Transition to Subcutaneous Insulin

Ensure patient is tolerating oral intake. Administer long-acting insulin 1-2 hours before discontinuing insulin drip. In new-onset Type 1 diabetes: Begin insulin education, carbohydrate counting, glucose monitoring. In known diabetics: Identify and address the precipitating factor.

Clinical Pearls

Cerebral edema is the leading cause of death in pediatric DKA; cautious fluid resuscitation and avoiding rapid osmolarity shifts are paramount. In adult DKA, fluid resuscitation is more aggressive; cerebral edema is exceedingly rare. Always check potassium before starting insulin; hypokalemia with insulin can be fatal. Euglycemic DKA from SGLT2 inhibitors is a diagnostic pitfall; check ketones even with normal glucose. The med-peds physician should be comfortable with both protocols and recognize the critical differences in fluid management.

References

1. Wolfsdorf JI, Glaser N, Agus M, et al. ISPAD Clinical Practice Consensus Guidelines 2018: Diabetic ketoacidosis and hyperglycemic hyperosmolar state. Pediatr Diabetes. 2018;19(Suppl 27):155-177.
2. Kitabchi AE, Umpierrez GE, Miles JM, Fisher JN. Hyperglycemic crises in adult patients with diabetes. Diabetes Care. 2009;32(7):1335-1343.
3. Glaser N, Barnett P, McCaslin I, et al. Risk factors for cerebral edema in children with diabetic ketoacidosis. N Engl J Med. 2001;344(4):264-269.
4. Dhatariya KK, Vellanki P. Treatment of diabetic ketoacidosis (DKA)/hyperglycemic hyperosmolar state (HHS): Novel advances in the management of hyperglycemic crises. Curr Diab Rep. 2017;17(8):33.

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