What is the initial treatment for a patient presenting with diabetic ketoacidosis (DKA)?

Treatment Algorithm for Diabetic Ketoacidosis

Initial Assessment and Diagnostic Workup

Begin immediate fluid resuscitation with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in the first hour for adults) to restore intravascular volume and tissue perfusion. 1, 2

Obtain the following laboratory studies immediately upon presentation 1, 2:

• Plasma glucose, serum ketones (preferably β-hydroxybutyrate), electrolytes with calculated anion gap
• Venous blood gas (pH and bicarbonate)
• Blood urea nitrogen, creatinine, osmolality
• Complete blood count with differential
• Urinalysis with urine ketones
• Electrocardiogram
• Bacterial cultures (blood, urine, throat) if infection suspected 1

DKA diagnostic criteria include: blood glucose >250 mg/dL, arterial pH <7.3, serum bicarbonate <15 mEq/L, and presence of ketonemia or ketonuria 2

Fluid Resuscitation Protocol

After the initial hour of isotonic saline, adjust fluid choice based on corrected serum sodium and hydration status 2, 3:

• If corrected sodium is normal or elevated: use 0.45% NaCl at 4-14 mL/kg/hour
• If corrected sodium is low: continue 0.9% NaCl at similar rate
• When glucose falls to 200-250 mg/dL: switch to 5% dextrose with 0.45-0.75% saline while continuing insulin infusion 2, 3

Total fluid replacement should correct estimated deficits within 24 hours, typically 1.5 times the 24-hour maintenance requirements 4, 1

Insulin Therapy

For Moderate-to-Severe DKA or Critically Ill Patients

Administer continuous intravenous regular insulin infusion at 0.1 units/kg/hour (with or without an initial IV bolus of 0.1 units/kg) as the standard of care. 1, 2

Target glucose decline of 50-75 mg/dL per hour 1, 2:

• If glucose does not fall by 50 mg/dL in the first hour, verify adequate hydration status
• If hydration is adequate, double the insulin infusion rate every hour until achieving steady decline of 50-75 mg/dL/hour 1, 2

Continue insulin infusion until complete resolution of ketoacidosis (pH >7.3, serum bicarbonate ≥18 mEq/L, anion gap ≤12 mEq/L) regardless of glucose levels. 1, 2, 3

For Mild-to-Moderate Uncomplicated DKA

For hemodynamically stable, alert patients with mild-to-moderate DKA, subcutaneous rapid-acting insulin analogs at 0.15 units/kg every 2-3 hours combined with aggressive fluid management are equally effective, safer, and more cost-effective than IV insulin 1, 2, 5

This approach requires adequate fluid replacement, frequent point-of-care glucose monitoring, and treatment of concurrent infections 1, 2

Potassium Management

Despite total-body potassium depletion averaging 3-5 mEq/kg, many patients present with normal or elevated potassium due to acidosis and insulin deficiency. 4, 2

Critical potassium thresholds 4, 1, 2:

• If K+ <3.3 mEq/L: DO NOT START INSULIN—delay insulin therapy and aggressively replace potassium until K+ ≥3.3 mEq/L to prevent life-threatening cardiac arrhythmias, respiratory muscle weakness, and death 4, 1, 2
• If K+ 3.3-5.5 mEq/L: add 20-30 mEq potassium per liter of IV fluid (use 2/3 KCl or potassium-acetate and 1/3 KPO₄) once adequate urine output confirmed 4, 1, 2
• If K+ >5.5 mEq/L: withhold potassium initially but monitor closely every 2-4 hours, as levels will drop rapidly with insulin therapy 4, 2

Target serum potassium of 4-5 mEq/L throughout treatment 4, 2

Bicarbonate Therapy

Bicarbonate is NOT recommended for DKA patients with pH >6.9-7.0, as multiple studies show no difference in resolution of acidosis or time to discharge, and it may worsen ketosis, cause hypokalemia, and increase cerebral edema risk. 4, 1, 2

If pH <6.9 after initial treatment in adults, consider adding 100 mmol sodium bicarbonate to 400 mL sterile water infused at 200 mL/hour 4

Monitoring During Treatment

Check the following every 2-4 hours until DKA resolution 1, 2:

• Blood glucose (capillary or venous)
• Serum electrolytes (sodium, potassium, chloride)
• Venous pH and bicarbonate
• Anion gap calculation
• Blood urea nitrogen, creatinine, osmolality

Direct measurement of β-hydroxybutyrate in blood is the preferred method for monitoring ketone clearance, as the nitroprusside method only measures acetoacetic acid and acetone 1, 2, 3

DKA Resolution Criteria

DKA is resolved when ALL of the following criteria are met: glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, venous pH >7.3, and anion gap ≤12 mEq/L. 1, 2, 3

Transition to Subcutaneous Insulin

Administer basal insulin (glargine or detemir) subcutaneously 2-4 hours BEFORE stopping the IV insulin infusion to prevent recurrence of ketoacidosis and rebound hyperglycemia—this is the most critical step to avoid DKA recurrence. 1, 2

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

Once the patient can tolerate oral intake, initiate a multiple-dose regimen combining short/rapid-acting insulin with intermediate/long-acting insulin 4, 1, 2:

• For newly diagnosed patients: start with approximately 0.5-1.0 units/kg/day total daily dose
• For known diabetics: resume previous regimen or adjust based on recent control

Special Considerations

Euglycemic DKA

For patients with glucose <250 mg/dL but meeting other DKA criteria (often associated with SGLT2 inhibitor use, pregnancy, or reduced caloric intake) 3:

• Add dextrose to IV fluids immediately while continuing insulin infusion at full dose
• Continue insulin until ketoacidosis resolves, not until glucose normalizes
• SGLT2 inhibitors must be discontinued immediately and held for 3-4 days after metabolic stability 2

Severe Hypokalemia at Presentation

Begin isotonic saline at 15-20 mL/kg/hour while holding insulin 1 Add 20-40 mEq/L potassium to IV fluids once renal function confirmed 1 Obtain ECG to assess for cardiac effects of hypokalemia 1 Continue aggressive potassium repletion until K+ ≥3.3 mEq/L before starting insulin 1

Common Pitfalls to Avoid

Stopping IV insulin without prior administration of subcutaneous basal insulin is the most common error leading to DKA recurrence and rebound hyperglycemia. 1, 2

Other critical errors include 2, 3, 6:

• Premature termination of insulin therapy before complete resolution of ketosis (all four resolution criteria must be met)
• Interrupting insulin infusion when glucose falls below 250 mg/dL—instead, add dextrose to IV fluids and continue insulin
• Inadequate potassium monitoring and replacement, which is a leading cause of mortality in DKA
• Overly rapid correction of osmolality, which increases cerebral edema risk, particularly in children
• Failing to identify and treat precipitating causes (infection, myocardial infarction, medication non-adherence)

Identification and Treatment of Precipitating Factors

Identify and treat underlying causes concurrently with DKA management 1, 2:

• Infection (most common): administer appropriate antibiotics after obtaining cultures
• Myocardial infarction or stroke: obtain ECG, cardiac enzymes, neurological examination as indicated
• Insulin omission or inadequacy: review insulin regimen and adherence
• Medications: discontinue SGLT2 inhibitors, review other diabetogenic drugs
• Pancreatitis, trauma, alcohol abuse: treat as clinically indicated