Diabetic Ketoacidosis: Symptoms and Insulin Treatment
Continuous intravenous insulin is the standard of care for critically ill and mentally obtunded patients with diabetic ketoacidosis (DKA), with aggressive fluid management to restore circulatory volume and tissue perfusion. 1
Symptoms of DKA
- Early symptoms typically develop gradually over hours or days and include drowsiness, flushed face, thirst, loss of appetite, and fruity odor on the breath 2
- Blood and urine tests show elevated glucose and ketones 2
- More severe symptoms include heavy breathing and rapid pulse 2
- If left untreated, DKA can progress to nausea, vomiting, stomach pain, dehydration, loss of consciousness, or death 2
Initial Management
- Aggressive fluid resuscitation with isotonic saline at 15-20 mL/kg/hour is essential to restore circulatory volume and tissue perfusion 1
- Identify and treat any underlying cause of DKA such as sepsis, myocardial infarction, or stroke 1
- Management goals include restoration of circulatory volume, resolution of hyperglycemia, and correction of electrolyte imbalance and acidosis 3
Insulin Therapy
- For critically ill patients, administer continuous intravenous regular insulin at an initial rate of 0.1 units/kg/hour 1, 4
- Recent evidence suggests avoiding an initial insulin bolus as it may lead to more adverse effects (particularly hypokalemia) without significant benefits in resolution time 5
- Continue insulin therapy until resolution of ketoacidosis (pH >7.3, serum bicarbonate ≥18 mEq/L, and anion gap ≤12 mEq/L) regardless of glucose levels 1, 6
- When serum glucose reaches 250 mg/dL, change fluid to 5% dextrose with 0.45-0.75% NaCl while continuing insulin therapy to resolve ketosis 1
Fluid Management
- After initial volume expansion with isotonic saline, subsequent fluid choice depends on hydration status and electrolyte levels 1
- Continue fluid replacement to correct estimated deficits within the first 24 hours 4
Electrolyte Management
- Monitor potassium levels closely as insulin administration can cause hypokalemia 1, 4
- Include 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO₄) in the infusion once renal function is assured 1
- Maintain serum potassium between 4-5 mmol/L 1, 4
- Bicarbonate administration is generally not recommended unless pH is <6.9 4, 6
Monitoring During Treatment
- Draw blood every 2-4 hours to determine serum electrolytes, glucose, blood urea nitrogen, creatinine, osmolality, and venous pH 1, 4
- Follow venous pH and anion gap to monitor resolution of acidosis 1
- Direct measurement of β-hydroxybutyrate in blood is the preferred method for monitoring DKA 1, 4
Transition to Subcutaneous Insulin
- When transitioning to subcutaneous insulin, administer basal insulin 2-4 hours before stopping the intravenous insulin to prevent recurrence of ketoacidosis and rebound hyperglycemia 3, 1
- For mild or moderate uncomplicated DKA, subcutaneous rapid-acting insulin analogs combined with aggressive fluid management can be as effective as intravenous insulin 1
Resolution Parameters
- DKA resolution requires glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, venous pH >7.3, and anion gap ≤12 mEq/L 1, 4
- Ketonemia typically takes longer to clear than hyperglycemia 1
Common Pitfalls to Avoid
- Premature termination of insulin therapy before complete resolution of ketosis can lead to recurrence 6
- Inadequate fluid resuscitation and electrolyte replacement can worsen outcomes 6
- Bicarbonate use generally provides no benefit in DKA resolution or time to discharge 3, 4