What is the protocol for managing Diabetic Ketoacidosis (DKA) and Hyperosmolar Hyperglycemic State (HHS)?

Management Protocol for DKA and HHS

Begin immediate fluid resuscitation with isotonic saline (0.9% NaCl) at 15-20 mL/kg/h during the first hour for both DKA and HHS, followed by continuous IV insulin for DKA (after confirming potassium >3.3 mEq/L), while delaying insulin in HHS until osmolality stops declining with fluids alone unless ketonemia is present. 1, 2

Diagnostic Criteria

DKA Diagnosis

• Blood glucose >250 mg/dL 1
• Arterial pH <7.3 1, 3
• Serum bicarbonate <15 mEq/L 1, 3
• Moderate ketonuria or ketonemia 1
• Anion gap >10-12 mEq/L 3

HHS Diagnosis

• Blood glucose >600 mg/dL 1
• Arterial pH >7.3 1
• Serum bicarbonate >15 mEq/L 1
• Effective serum osmolality ≥320 mOsm/kg (calculated as 2×Na+ + glucose + urea) 1, 2
• Only small ketones (≤3.0 mmol/L) 2

Essential Initial Laboratory Tests

• Arterial blood gases for pH documentation 3
• Measure β-hydroxybutyrate specifically—never rely on nitroprusside-based tests for monitoring 3
• Electrolytes with calculated anion gap 3
• BUN/creatinine to assess renal function 3
• Correct serum sodium by adding 1.6 mEq/L for each 100 mg/dL glucose above 100 mg/dL 3

Initial Fluid Resuscitation (First Hour)

Adult Patients

• Administer 0.9% NaCl at 15-20 mL/kg/h (typically 1-1.5 L) during the first hour 1, 3
• In elderly or those with cardiac/renal compromise, use more cautious rates with closer hemodynamic monitoring 1

Pediatric Patients (<20 years)

• Use 0.9% NaCl at 10-20 mL/kg/h 1
• Do not exceed 50 mL/kg over the first 4 hours to minimize cerebral edema risk 1

Insulin Therapy: Critical Differences Between DKA and HHS

DKA Insulin Protocol

• Start continuous IV regular insulin at 0.1 units/kg/h (typically 5-10 units/hour) after initial fluid resuscitation 1
• Never start insulin if serum potassium <3.3 mEq/L—this can cause fatal cardiac arrhythmias 1
• Continue IV insulin until resolution of ketonemia 4

HHS Insulin Protocol

• Withhold insulin until blood glucose stops falling with IV fluids alone, unless ketonemia is present 5, 2
• Fluid replacement alone will cause blood glucose to fall in HHS 5
• Early insulin use before adequate fluid resuscitation may be detrimental 5
• Once indicated, use fixed rate IV insulin infusion 2

Potassium Replacement Protocol

• Once renal function is assured, add 20-30 mEq/L potassium to IV fluids 1, 3
• Use 2/3 KCl and 1/3 KPO4 formulation 1, 3
• Add potassium regardless of initial potassium level, as insulin therapy drives potassium intracellularly 1
• Continue until patient is stable and can tolerate oral supplementation 3

Ongoing Fluid Management

After First Hour

• Target correction of estimated deficits within 24 hours 3
• Serum osmolality change should not exceed 3-8 mOsm/kg/h 3, 2
• For HHS specifically, aim for osmolality reduction of 3.0-8.0 mOsm/kg/h to minimize neurological complications 2
• An initial rise in sodium level is expected in HHS and is not itself an indication for hypotonic fluids 5

Glucose Management During Treatment

• Add 5% or 10% glucose infusion once blood glucose falls to <200 mg/dL in DKA or <14 mmol/L (252 mg/dL) in HHS 1, 2
• Target blood glucose 10-15 mmol/L (180-270 mg/dL) in first 24 hours for HHS 2

Monitoring Requirements

• Monitor vital signs, mental status, fluid input/output hourly 1
• Serial measurements of electrolytes, glucose, and acid-base status every 2-4 hours 3
• Track hemodynamic parameters and blood pressure improvement 3
• Calculate serum osmolality regularly to monitor treatment response 5, 2

Resolution Criteria

DKA Resolution

• Blood glucose <200 mg/dL 1
• Anion gap ≤12 mEq/L 1
• Serum bicarbonate ≥15 mEq/L 1
• Venous pH >7.3 1

HHS Resolution

• Osmolality <300 mOsm/kg 2
• Hypovolemia corrected (urine output ≥0.5 mL/kg/h) 2
• Cognitive status returned to pre-morbid state 2
• Blood glucose <15 mmol/L (270 mg/dL) 2

Transition to Subcutaneous Insulin

• Administer basal subcutaneous insulin 2-4 hours before discontinuing IV insulin to prevent rebound hyperglycemia 1, 4
• Common pitfall: premature termination of IV insulin or insufficient timing/dosing of subcutaneous insulin 4

Therapies to Avoid

• Do not use bicarbonate therapy routinely—it has not been shown to improve outcomes and may worsen hypokalemia 1
• Never rely on urine ketone testing alone for diagnosis 3
• Avoid rapid correction of metabolic abnormalities in younger patients to decrease cerebral edema risk 6

Special Considerations

Mixed DKA/HHS Cases

• Up to one-third of patients may have mixed features 6, 2
• Manage using the same three-pronged approach: fluids, insulin, and electrolyte replacement 6
• Tailor therapy according to prominent clinical features 6

Typical Deficits in DKA

• Water: 6-9 liters 3
• Sodium: 7-10 mEq/kg 3
• Potassium: 3-5 mEq/kg 3
• Chloride: 5-13 mEq/kg 3
• Phosphate: 3-5 mmol/kg 3

HHS-Specific Considerations

• Fluid losses typically 100-220 mL/kg (use caution in elderly) 2
• HHS has higher mortality than DKA and develops over days rather than hours 5, 7
• Risk of complications including myocardial infarction, stroke, seizures, cerebral edema, and central pontine myelinolysis 5