Management of Diabetic Ketoacidosis (DKA) vs Hyperglycemic Hyperosmolar State (HHS) in Pediatric Patients

In pediatric patients, DKA and HHS require immediate fluid resuscitation with 0.9% normal saline at 10-20 mL/kg over the first hour (never exceeding 50 mL/kg in the first 4 hours), followed by continuous insulin infusion WITHOUT an initial bolus—this critical difference from adult protocols prevents cerebral edema, the leading cause of death in pediatric DKA. 1, 2

Initial Diagnostic Differentiation

DKA Diagnostic Criteria

Blood glucose >250 mg/dL 2, 3
Venous pH <7.3 2, 3
Serum bicarbonate <15 mEq/L 2, 3
Moderate ketonuria or ketonemia 2, 3

HHS Diagnostic Criteria

Blood glucose ≥600 mg/dL 2
Venous pH ≥7.3 2
Serum bicarbonate ≥15 mEq/L 2
Altered mental status or severe dehydration 2

Severity Classification for DKA

Mild DKA: pH 7.25-7.30, bicarbonate 15-18 mEq/L, alert mental status 3
Moderate DKA: pH 7.00-7.24, bicarbonate 10-15 mEq/L, drowsy mental status 3
Severe DKA: pH <7.00, bicarbonate <10 mEq/L, stuporous mental status 3

Immediate Laboratory Assessment

Obtain STAT: 2, 4

Arterial or venous blood gases (venous pH is 0.03 units lower than arterial and sufficient for monitoring) 2, 3
Complete blood count with differential 2
Comprehensive metabolic panel including glucose, electrolytes, BUN, creatinine, calcium, phosphorus 2
Direct blood β-hydroxybutyrate measurement (NOT nitroprusside-based urine ketones, which miss the predominant ketoacid) 3
Urinalysis 2
Electrocardiogram 2, 4
Cultures (blood, urine, throat) if infection suspected 2, 4

Critical pitfall: Never rely on urine ketones or nitroprusside methods for monitoring treatment response—they only measure acetoacetate and acetone, completely missing β-hydroxybutyrate, and paradoxically worsen during treatment as β-OHB converts to acetoacetate. 3

Fluid Resuscitation Protocol

Phase 1: Initial Resuscitation (First Hour)

Administer 0.9% normal saline at 10-20 mL/kg over the first hour 1, 2
NEVER exceed 50 mL/kg total fluid volume in the first 4 hours—this is the most critical threshold for preventing cerebral edema 1
Do NOT start insulin during this phase—wait until hemodynamic stability is achieved 1

Phase 2: Deficit Replacement (After First Hour)

Calculate corrected sodium: Add 1.6 mEq/L for each 100 mg/dL glucose above 100 mg/dL 2, 1, 3

Fluid selection based on corrected sodium: 2, 1

If corrected sodium is normal or elevated: Switch to 0.45% NaCl (half-normal saline) at 4-14 mL/kg/hour
If corrected sodium is low: Continue 0.9% NaCl at reduced rates of 4-14 mL/kg/hour

Total rehydration strategy: 2, 1

Calculate total fluid as 1.5 times the 24-hour maintenance requirements (approximately 5 mL/kg/hour)
Do NOT exceed 2 times maintenance requirements
Replace estimated deficit over 36-48 hours

Critical osmolality monitoring: The induced change in serum osmolality must NEVER exceed 3 mOsm/kg/hour to prevent cerebral edema 2, 1

Insulin Therapy Protocol

Pediatric-Specific Insulin Initiation

DO NOT give IV bolus insulin in pediatric patients—this is a critical difference from adult protocols and prevents dangerous potassium shifts 1, 4

Continuous Insulin Infusion

Start continuous IV regular insulin at 0.05-0.1 units/kg/hour (typically 0.1 units/kg/hour) ONLY after initial fluid resuscitation 2, 1, 3
Target glucose reduction of 50-100 mg/dL per hour 1, 3
If glucose does not fall by 50 mg/dL in the first hour, verify hydration status and double insulin infusion hourly until steady decline achieved 2

Glucose Management During Treatment

When plasma glucose reaches 250 mg/dL in DKA or 300 mg/dL in HHS, decrease insulin to 0.05-0.1 units/kg/hour 2
Add dextrose 5-10% to IV fluids at this point 2, 1
Continue insulin infusion until acidosis resolves—do NOT stop based on glucose normalization alone 2

Electrolyte Management

Potassium Replacement Protocol

Absolute contraindication: If initial potassium is <3.3 mEq/L, DELAY insulin therapy and aggressively replace potassium first to prevent fatal cardiac arrhythmias 3, 4

Standard potassium replacement: 2, 1, 3

Once serum potassium falls below 5.5 mEq/L AND adequate urine output confirmed, add 20-30 mEq/L potassium to IV fluids
Use mixture of 2/3 KCl (or potassium acetate) and 1/3 KPO4
Target serum potassium 4-5 mEq/L throughout treatment

Phosphate Considerations

Routine phosphate replacement is NOT necessary 2
Consider careful phosphate replacement only if serum phosphate <1.0 mg/dL AND patient has cardiac dysfunction, anemia, or respiratory depression 2

Bicarbonate Therapy

Generally NOT recommended 3
Consider only if pH <6.9 2
No beneficial effect demonstrated if pH ≥7.0 2

Monitoring Protocol

Continuous Monitoring

Vital signs and neurological status continuously 1
Blood glucose hourly or more frequently 1

Laboratory Monitoring Every 2-4 Hours

Serum electrolytes (sodium, potassium, chloride) 2, 1, 3
Glucose 2, 1
BUN and creatinine 2, 1
Venous pH (arterial blood gases NOT needed after initial diagnosis) 2, 3
Calculated anion gap 2, 3
Serum osmolality 2, 1
Direct blood β-hydroxybutyrate 3

Cerebral Edema Recognition and Prevention

High-Risk Features

Cerebral edema occurs in 0.7-1.0% of pediatric DKA cases with 70% mortality once clinical symptoms develop 2
Most common in newly diagnosed diabetes but can occur in known diabetics 2

Early Warning Signs (Act Immediately)

Lethargy beyond expected improvement 2
Headache 2
Behavioral changes 2

Late Signs (Medical Emergency)

Deteriorating level of consciousness 2
Seizures 2
Incontinence 2
Pupillary changes 2
Bradycardia 2
Respiratory arrest 2

Prevention Strategies

Never exceed 50 mL/kg fluid in first 4 hours 1
Limit osmolality decline to <3 mOsm/kg/hour 2, 1
Use isotonic fluids initially 1
Gradual correction of hyperglycemia and hyperosmolality 2

Resolution Criteria

DKA is resolved when ALL of the following are met: 2, 3

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

HHS is resolved when: 2

Glucose 250-300 mg/dL maintained until hyperosmolarity and mental status improve
Patient becomes clinically stable

Transition to Subcutaneous Insulin

Critical Timing

Administer basal insulin (glargine or detemir) 2-4 hours BEFORE stopping IV insulin to prevent rebound hyperglycemia and DKA recurrence 3, 4
This is the most common error leading to DKA recurrence 4

Dosing for Newly Diagnosed Patients

Start with 0.5-1.0 units/kg/day as multidose regimen of short- and intermediate-/long-acting insulin 2
Adjust based on subsequent glucose monitoring 2

Dosing for Known Diabetics

Resume previous insulin regimen if adequate 2
Adjust based on precipitating factors 2

Key Differences: Pediatric vs Adult DKA Management

NO IV insulin bolus in children (adults receive 0.1 units/kg bolus) 1, 4
Stricter fluid limits (50 mL/kg maximum in first 4 hours) 1
Lower insulin infusion rates (0.05-0.1 vs 0.1 units/kg/hour) 2, 1
More conservative osmolality correction (<3 mOsm/kg/hour) 2, 1
Higher cerebral edema risk requiring intensive neurological monitoring 2, 1

Common Pitfalls to Avoid

Excessive fluid administration: Never exceed 50 mL/kg in first 4 hours—this is the primary modifiable risk factor for cerebral edema 1
Starting insulin too early: Wait until after initial fluid resuscitation 1
Giving IV insulin bolus: This is an adult protocol—never use in children 1, 4
Starting insulin with K+ <3.3 mEq/L: This causes life-threatening arrhythmias 3, 4
Using hypotonic fluids initially: This accelerates osmotic shifts and increases cerebral edema risk 1
Stopping insulin when glucose normalizes: Continue until acidosis resolves (pH >7.3, bicarbonate ≥18 mEq/L) 2, 3
Stopping IV insulin without prior basal insulin: Give basal insulin 2-4 hours before stopping IV infusion 3, 4
Monitoring urine ketones instead of blood β-hydroxybutyrate: Urine ketones are unreliable and misleading during treatment 3
Repeating arterial blood gases: Venous pH is sufficient after initial diagnosis 2, 3

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