Treatment of Diabetic Ketoacidosis (DKA)
For moderate to severe DKA, initiate continuous intravenous regular insulin at 0.1 units/kg/hour combined with aggressive isotonic saline resuscitation at 15-20 mL/kg/hour, while closely monitoring and replacing potassium to maintain levels between 4-5 mEq/L. 1
Initial Assessment and Diagnosis
Before starting treatment, confirm DKA with the diagnostic triad 1:
- Blood glucose >250 mg/dL (though euglycemic DKA can occur, especially with SGLT2 inhibitors)
- Arterial pH <7.3
- Serum bicarbonate <15 mEq/L
- Presence of ketonemia or ketonuria
Obtain comprehensive laboratory evaluation including plasma glucose, electrolytes with calculated anion gap, serum ketones (β-hydroxybutyrate preferred), blood urea nitrogen, creatinine, arterial blood gases, complete blood count, urinalysis, and electrocardiogram 1, 2. If infection is suspected, obtain blood and urine cultures and start appropriate antibiotics 1.
Fluid Resuscitation
Begin immediately with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in the first hour for average adults). 1 This aggressive fluid replacement is critical for restoring circulatory volume and tissue perfusion 1.
After the initial hour, adjust fluid choice based on hydration status, serum electrolytes, and urine output 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 Total fluid replacement should correct estimated deficits within 24 hours 1.
Insulin Therapy
For Moderate to Severe DKA:
Start continuous intravenous regular insulin infusion at 0.1 units/kg/hour without an initial bolus. 1, 2 This is the standard of care for critically ill and mentally obtunded patients 3.
If plasma glucose does not fall by 50 mg/dL in the first hour, verify adequate hydration, then double the insulin infusion rate hourly until achieving a steady glucose decline of 50-75 mg/hour 1.
Critical: Continue insulin infusion until complete resolution of ketoacidosis (pH >7.3, bicarbonate ≥18 mEq/L, anion gap ≤12 mEq/L) regardless of glucose levels. 1 Interrupting insulin when glucose normalizes is a common error that causes persistent or worsening ketoacidosis 1, 4.
For Mild to Moderate Uncomplicated DKA:
Subcutaneous rapid-acting insulin analogs combined with aggressive fluid management are equally effective and safer than IV insulin in stable patients 3, 1. This approach may be used in emergency departments or step-down units 3.
Electrolyte Management
Potassium Replacement (Critical):
If serum K+ <3.3 mEq/L, delay insulin therapy and aggressively replace potassium first to prevent life-threatening cardiac arrhythmias and respiratory muscle weakness. 1 Despite possible hyperkalemia at presentation, total body potassium depletion is universal in DKA, and insulin will drive potassium intracellularly 1.
Once K+ ≥3.3 mEq/L and adequate urine output is confirmed, add 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO₄) to IV fluids 1, 2. Target serum potassium of 4-5 mEq/L throughout treatment 1.
If K+ >5.5 mEq/L initially, withhold potassium but monitor closely as levels will drop rapidly with insulin therapy 1.
Bicarbonate (Generally NOT Recommended):
Do not administer bicarbonate for DKA patients with pH >7.0, as studies show no difference in resolution of acidosis or time to discharge, and it may worsen ketosis, hypokalemia, and increase cerebral edema risk. 3, 1 The FDA label indicates bicarbonate use only for severe metabolic acidosis, but guideline evidence does not support routine use in DKA 5.
Monitoring During Treatment
Draw blood every 2-4 hours to measure serum electrolytes, glucose, blood urea nitrogen, creatinine, osmolality, and venous pH 1, 2. Venous pH (typically 0.03 units lower than arterial pH) and anion gap should be followed to monitor acidosis resolution 1, 4.
Direct measurement of β-hydroxybutyrate in blood is the preferred monitoring method, as the nitroprusside method only detects acetoacetic acid and acetone. 1, 4
Target glucose between 150-200 mg/dL until DKA resolution parameters are met 1.
Resolution Criteria
DKA is resolved when ALL of the following are achieved 1, 4:
- Glucose <200 mg/dL
- Serum bicarbonate ≥18 mEq/L
- Venous pH >7.3
- Anion gap ≤12 mEq/L
Transition to Subcutaneous Insulin
Once DKA is resolved and the patient can eat, administer basal insulin (intermediate or long-acting) 2-4 hours BEFORE stopping the IV insulin infusion. 3, 1, 2 This overlap is essential to prevent recurrence of ketoacidosis and rebound hyperglycemia—stopping IV insulin without prior basal insulin administration is the most common error leading to DKA recurrence 2.
Start a multiple-dose schedule using a combination of short/rapid-acting and intermediate/long-acting insulin 3, 2.
Treatment of Precipitating Causes
Identify and treat underlying causes such as infection, myocardial infarction, stroke, pancreatitis, trauma, or insulin omission 1, 4. Discontinue SGLT2 inhibitors if present, as they must be stopped 3-4 days before any planned surgery to prevent euglycemic DKA. 1
Critical Pitfalls to Avoid
- Never stop insulin infusion when glucose falls below 250 mg/dL—instead add dextrose to fluids while continuing insulin until ketoacidosis resolves 1, 4
- Never start insulin if K+ <3.3 mEq/L—correct potassium first 1
- Never stop IV insulin without giving basal insulin 2-4 hours prior—this causes DKA recurrence 3, 2
- Inadequate potassium monitoring and replacement is a leading cause of mortality in DKA 1
- Overly rapid correction of osmolality increases cerebral edema risk, particularly in children 1