What is the initial treatment for a patient presenting with Diabetic Ketoacidosis (DKA)?

Initial Treatment of Diabetic Ketoacidosis

Begin immediate fluid resuscitation with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour for the first hour, followed by continuous intravenous regular insulin infusion at 0.1 units/kg/hour after confirming serum potassium ≥3.3 mEq/L. 1, 2

Immediate Assessment and Stabilization

Upon presentation, obtain the following laboratory studies STAT 3, 1:

• Plasma glucose, venous blood gas (pH), serum ketones (preferably β-hydroxybutyrate)
• Complete metabolic panel with calculated anion gap
• Serum osmolality, phosphorus, magnesium
• Complete blood count with differential
• Electrocardiogram
• Urinalysis with urine ketones
• Blood, urine, and throat cultures if infection suspected 1, 2

DKA is confirmed when all three criteria are present: blood glucose >250 mg/dL, venous pH <7.3 or bicarbonate <15 mEq/L, and presence of ketonemia or ketonuria. 2, 4

Fluid Resuscitation Protocol

Start with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 liters in average adults) during the first hour. 1, 5, 2 This aggressive initial fluid replacement is critical for restoring tissue perfusion and improving insulin sensitivity. 2

After the first hour, adjust fluid choice based on 3, 2:

• Hydration status and hemodynamic stability
• Corrected serum sodium levels
• Urine output adequacy

When serum glucose reaches 250 mg/dL, switch to 5% dextrose with 0.45-0.75% saline while continuing insulin infusion. 2 This prevents hypoglycemia while allowing insulin to continue resolving ketoacidosis—a common pitfall is stopping insulin when glucose normalizes, which leads to persistent or recurrent DKA. 2

Insulin Therapy Initiation

Critical potassium checkpoint: Do NOT start insulin if serum potassium is <3.3 mEq/L. 1, 2 This is an absolute contraindication, as insulin will drive potassium intracellularly and can precipitate life-threatening cardiac arrhythmias, respiratory muscle weakness, or cardiac arrest. 3, 2

If K+ <3.3 mEq/L 1, 2:

• Continue aggressive fluid resuscitation
• Add 20-40 mEq/L potassium to IV fluids (2/3 KCl and 1/3 KPO₄)
• Confirm adequate urine output before potassium replacement
• Delay insulin until K+ ≥3.3 mEq/L

Once K+ ≥3.3 mEq/L, administer IV bolus of regular insulin 0.1 units/kg, followed immediately by continuous infusion at 0.1 units/kg/hour. 1, 2 This is the preferred method for moderate to severe DKA. 3, 1

Target glucose decline of 50-75 mg/dL per hour. 1, 2 If glucose does not fall by at least 50 mg/dL in the first hour, verify adequate hydration status, then double the insulin infusion rate hourly until achieving steady decline. 1, 2

Electrolyte Management

Potassium Replacement

Despite total-body potassium depletion averaging 3-5 mEq/kg, many patients present with normal or elevated potassium due to acidosis and insulin deficiency. 2 Insulin therapy will unmask this depletion rapidly. 2

Once K+ falls below 5.5 mEq/L and adequate urine output is confirmed, add 20-30 mEq potassium per liter of IV fluid (2/3 KCl and 1/3 KPO₄). 3, 1, 2 Target serum potassium of 4-5 mEq/L throughout treatment. 2

Bicarbonate Administration

Bicarbonate is NOT recommended for pH >6.9-7.0. 3, 1, 2 Multiple studies show no benefit in resolution time or clinical outcomes, and bicarbonate may worsen ketosis, cause hypokalemia, and increase cerebral edema risk. 1, 2

If pH <6.9 after initial fluid resuscitation, consider 100 mmol sodium bicarbonate in 400 mL sterile water infused at 200 mL/hour for adults only. 3

Phosphate Monitoring

While routine phosphate replacement is not recommended, monitor levels and consider careful replacement if serum phosphate <1.0 mg/dL, particularly in patients with cardiac dysfunction, anemia, or respiratory depression. 3

Monitoring Protocol

Check blood glucose every 2-4 hours and measure serum electrolytes, venous pH, and anion gap every 2-4 hours until DKA resolves. 1, 2 Direct measurement of β-hydroxybutyrate in blood is the preferred method for monitoring ketone clearance. 1, 2

DKA Resolution Criteria

DKA is resolved when ALL of the following are met: 1, 2

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

Continue insulin infusion until complete resolution of ketoacidosis, regardless of glucose levels. 1, 5, 2 Premature termination of insulin before ketosis resolves is a leading cause of treatment failure. 2

Transition to Subcutaneous Insulin

Administer basal insulin (glargine or detemir) subcutaneously 2-4 hours BEFORE stopping IV insulin infusion. 1, 2 This overlap period 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. 1, 2

Continue IV insulin for 1-2 hours after administering subcutaneous insulin to allow for absorption. 1

Alternative Approach for Mild-Moderate Uncomplicated DKA

For hemodynamically stable, alert patients with mild-moderate DKA, subcutaneous rapid-acting insulin analogs combined with aggressive fluid management may be equally effective, safer, and more cost-effective than IV insulin. 1, 2 However, continuous IV insulin remains the standard of care for critically ill and mentally obtunded patients. 1, 2

Treatment of Precipitating Causes

Identify and treat underlying triggers concurrently: 1, 2

• Infections (most common)—obtain cultures and start appropriate antibiotics
• Myocardial infarction or stroke
• Insulin omission or inadequate dosing
• SGLT2 inhibitors (discontinue immediately; must be stopped 3-4 days before any planned surgery) 1, 2
• Pancreatitis, trauma, or new diabetes diagnosis

Critical Pitfalls to Avoid

• Never start insulin with K+ <3.3 mEq/L—this can cause fatal arrhythmias 1, 2
• Never stop IV insulin when glucose normalizes—continue until complete resolution of ketoacidosis 2
• Never stop IV insulin without prior basal insulin administration—give basal insulin 2-4 hours before stopping IV 1, 2
• Never give bicarbonate for pH >6.9—it worsens outcomes 1, 2
• Never forget to add dextrose when glucose falls below 250 mg/dL—prevents hypoglycemia while clearing ketones 2
• Monitor for cerebral edema, particularly in children and with overly rapid correction of osmolality 2