What is the best treatment approach for a patient with Diabetic Ketoacidosis (DKA)?

Management of Diabetic Ketoacidosis

Begin immediate aggressive fluid resuscitation with isotonic saline at 15-20 mL/kg/hour and start continuous IV regular insulin infusion at 0.1 units/kg/hour once serum potassium is ≥3.3 mEq/L. 1, 2

Diagnostic Confirmation

Before initiating treatment, confirm DKA with the following criteria 3, 4:

• Blood glucose >250 mg/dL (though euglycemic DKA can occur, especially with SGLT2 inhibitors) 4, 5
• Venous pH <7.3 3, 4
• Serum bicarbonate <15 mEq/L 3, 4
• Positive serum or urine ketones (β-hydroxybutyrate preferred over nitroprusside method) 3, 4
• Anion gap >10-12 mEq/L (calculated as [Na+] - [Cl- + HCO3-]) 3, 4

Obtain stat labs including complete metabolic panel, venous blood gases, serum ketones (β-hydroxybutyrate if available), complete blood count, urinalysis, and ECG 1, 2. Check for precipitating factors such as infection, MI, stroke, or medication nonadherence 1, 6.

Severity Classification

Classify severity to guide monitoring intensity 3, 4:

• Mild DKA: pH 7.25-7.30, bicarbonate 15-18 mEq/L, alert mental status 3, 4
• Moderate DKA: pH 7.00-7.24, bicarbonate 10-15 mEq/L, drowsy 3, 4
• Severe DKA: pH <7.00, bicarbonate <10 mEq/L, stupor/coma (requires ICU-level monitoring) 3, 4

Fluid Resuscitation Protocol

Start with isotonic (0.9%) saline at 15-20 mL/kg/hour for the first hour to restore intravascular volume and renal perfusion 3, 1, 2. For an average 70 kg adult, this equals 1-1.5 liters in the first hour 3.

After the initial hour, adjust fluid choice based on corrected serum sodium 3, 2:

• If corrected sodium is normal or elevated: Switch to 0.45% saline at 4-14 mL/kg/hour 3
• If corrected sodium is low: Continue 0.9% saline at 4-14 mL/kg/hour 3
• Correct sodium for hyperglycemia: Add 1.6 mEq/L to measured sodium for every 100 mg/dL glucose above 100 3, 4

Total fluid replacement should approximate 1.5 times the 24-hour maintenance requirements 1, 2. Monitor closely for fluid overload in patients with cardiac or renal compromise 4.

Potassium Management: Critical Safety Step

This is the most dangerous electrolyte abnormality in DKA and requires meticulous attention. 1, 2

Before Starting Insulin

If serum potassium <3.3 mEq/L: DO NOT START INSULIN 1, 2. This is an absolute contraindication that can cause fatal cardiac arrhythmias and respiratory muscle weakness 1. Instead:

• Continue aggressive fluid resuscitation 1
• Add 20-40 mEq/L potassium to IV fluids immediately 1
• Obtain ECG to assess for cardiac effects 1
• Recheck potassium every 1-2 hours until ≥3.3 mEq/L 1

During Treatment

Once adequate urine output is confirmed and potassium is known 3, 2:

• If K+ 3.3-5.5 mEq/L: Add 20-30 mEq/L potassium to each liter of IV fluid (use 2/3 KCl and 1/3 KPO4) 3, 1, 2
• If K+ >5.5 mEq/L: Withhold potassium initially but monitor closely as levels will drop rapidly with insulin therapy 1
• Target serum potassium 4-5 mEq/L throughout treatment 1, 2

Insulin Therapy Protocol

Initiation

Start continuous IV regular insulin infusion at 0.1 units/kg/hour (no initial bolus needed) once potassium ≥3.3 mEq/L 1, 2. For intubated or severely ill patients, the no-bolus approach is preferred 1.

Target glucose decline: 50-75 mg/dL per hour 2. If glucose does not fall by 50 mg/dL in the first hour 2:

• Verify adequate hydration status 2
• Double the insulin infusion rate hourly until achieving steady decline 2

Preventing Hypoglycemia

When blood glucose falls to 200-250 mg/dL, add dextrose (D5W) to IV fluids while continuing insulin infusion to clear ketones 2, 4. This is a common pitfall—never stop insulin when glucose normalizes, as ketoacidosis takes longer to resolve than hyperglycemia 1, 4.

Alternative for Mild-Moderate Uncomplicated DKA

For hemodynamically stable, alert patients with mild-moderate DKA, subcutaneous rapid-acting insulin analogs at 0.15 units/kg every 2-3 hours combined with aggressive fluid management can be as effective and more cost-effective than IV insulin 2, 7. However, this approach is not appropriate for severe DKA, intubated patients, or those with altered mental status 4.

Monitoring Protocol

Draw labs every 2-4 hours for serum electrolytes, glucose, BUN, creatinine, osmolality, and venous pH 1, 2, 4. After initial diagnosis, venous pH adequately monitors acidosis resolution without repeated arterial sticks 4.

If available, monitor β-hydroxybutyrate every 2-4 hours as the preferred ketone marker 1, 4. The nitroprusside method (urine ketones) is unreliable during treatment because it only measures acetoacetate and acetone, not β-hydroxybutyrate, and can paradoxically worsen as the patient improves 4.

Resolution Criteria

DKA is resolved when ALL of the following are met 1, 2, 4:

• Glucose <200 mg/dL 1, 2, 4
• Serum bicarbonate ≥18 mEq/L 1, 2, 4
• Venous pH >7.3 1, 2, 4
• Anion gap ≤12 mEq/L 1, 2, 4

Transition to Subcutaneous Insulin

Administer basal insulin (glargine or detemir) subcutaneously 2-4 hours BEFORE stopping IV insulin to prevent rebound hyperglycemia and DKA recurrence 1, 2, 4. This is the most common error leading to DKA recurrence 2.

For intubated patients who remain NPO after DKA resolution, continue IV insulin and supplement with subcutaneous regular insulin every 4 hours as needed 1.

Bicarbonate Therapy: Generally Not Recommended

Do not administer bicarbonate unless pH <6.9 4, 8. Bicarbonate provides no benefit in DKA resolution at higher pH levels and may worsen outcomes 4. If pH <6.9, add bicarbonate to IV fluids rather than giving as bolus 8.

Common Pitfalls to Avoid

• Starting insulin before checking potassium or when K+ <3.3 mEq/L (can cause fatal arrhythmias) 1, 2
• Stopping IV insulin when glucose normalizes (ketoacidosis persists longer than hyperglycemia) 1, 4
• Discontinuing IV insulin without prior basal insulin administration (causes DKA recurrence) 1, 2
• Using urine ketones to monitor treatment response (unreliable and misleading) 4
• Overly aggressive fluid resuscitation (increases cerebral edema risk, especially in children) 4
• Failing to identify and treat precipitating cause (leads to recurrence) 1, 4, 6

Special Considerations

For patients with insulin allergy presenting with severe DKA, continuous IV recombinant human insulin infusion may be tolerated even when subcutaneous administration causes allergic reactions 9. Consider haemodiafiltration in refractory cases 9.

Be aware that SGLT2 inhibitors modestly increase the risk of euglycemic DKA (glucose <250 mg/dL with ketoacidosis) 5. Maintain high clinical suspicion in these patients even with near-normal glucose levels 5.