What is the management approach for an adult patient with diabetic ketoacidosis (DKA), normal renal and hepatic function, and no significant medical history?

Management of Diabetic Ketoacidosis in Adults

For an adult patient with DKA and normal renal/hepatic function, begin immediate aggressive fluid resuscitation with isotonic saline at 15-20 mL/kg/hour (approximately 1-1.5 liters in the first hour), followed by continuous IV regular insulin at 0.1 units/kg/hour without an initial bolus, while simultaneously correcting electrolyte abnormalities and identifying the precipitating cause. 1, 2

Initial Assessment and Diagnosis

Confirm DKA Diagnosis

• Obtain immediate laboratory evaluation including venous blood gases, complete metabolic panel, complete blood count, urinalysis, and direct measurement of β-hydroxybutyrate 2
• DKA is confirmed when all three criteria are met: blood glucose >250 mg/dL, venous pH <7.3, and serum bicarbonate <15 mEq/L with moderate ketonuria or ketonemia 1, 2
• Calculate the anion gap using [Na+] - ([Cl-] + [HCO3-]); it should be >10-12 mEq/L in DKA 1, 2
• Correct serum sodium for hyperglycemia by adding 1.6 mEq/L for every 100 mg/dL glucose above 100 mg/dL 1, 2

Critical pitfall: Direct blood measurement of β-hydroxybutyrate is mandatory—do not rely on nitroprusside-based urine or serum ketone tests, as these only detect acetoacetate and acetone, completely missing β-hydroxybutyrate, the predominant ketoacid in DKA 2, 3. During treatment, β-hydroxybutyrate converts to acetoacetate, paradoxically making nitroprusside tests appear worse even as the patient improves 2, 3.

Identify Precipitating Factors

• Obtain bacterial cultures of urine, blood, and throat if infection is suspected 2
• Review medication history, particularly for insulin omission, SGLT2 inhibitor use, or recent medication changes 4, 5
• Assess for acute coronary syndrome, pregnancy, or other acute stressors 4, 5

Fluid Resuscitation

First Hour

• Administer isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour during the first hour to restore intravascular volume and renal perfusion 1, 2
• In a 70 kg patient, this equates to approximately 1-1.5 liters in the first hour 1

Subsequent Fluid Management

• After the first hour, switch to 0.45% NaCl at 4-14 mL/kg/hour if corrected serum sodium is normal or elevated 1
• Continue 0.9% NaCl at a similar rate if corrected serum sodium is low 1
• Total fluid replacement should correct estimated deficits within 24 hours 1, 2
• The induced change in serum osmolality should not exceed 3 mOsm/kg/H2O per hour 1

Critical pitfall: Monitor for fluid overload in patients with cardiac or renal compromise, though aggressive fluid resuscitation remains essential for DKA resolution 1, 2.

Insulin Therapy

Initial Insulin Administration

• Start continuous IV regular insulin infusion at 0.1 units/kg/hour without an initial bolus 1, 2
• For a 70 kg patient, this is approximately 7 units/hour 1
• Do not start insulin if serum potassium is <3.3 mEq/L—aggressively replace potassium first to prevent fatal cardiac arrhythmias 1, 2

Insulin Titration

• Expect plasma glucose to decrease at 50-75 mg/dL per hour 1, 2
• If glucose does not fall by 50 mg/dL in the first hour, verify adequate hydration, then double the insulin infusion rate hourly until achieving steady glucose decline of 50-75 mg/dL per hour 1, 2

Adding Dextrose

• When blood glucose falls to 200-250 mg/dL, add dextrose 5% to IV fluids while continuing insulin infusion 1, 2
• Never discontinue insulin when glucose normalizes—this is the most critical error in DKA management, as ketoacidosis takes longer to resolve than hyperglycemia 2, 3

Critical concept: The therapeutic target is ketone clearance and acidosis resolution, not glucose normalization. Continue insulin infusion until metabolic acidosis resolves, even if glucose is normal 2, 3.

Electrolyte Management

Potassium Replacement

• Check serum potassium before starting insulin therapy 1, 2
• If K+ <3.3 mEq/L: Hold insulin and aggressively replace potassium first 1, 2
• If K+ 3.3-5.5 mEq/L: Add 20-30 mEq/L potassium to IV fluids (2/3 KCl and 1/3 KPO4) 1, 2
• If K+ >5.5 mEq/L: Do not add potassium initially, but monitor closely as levels will fall with insulin therapy 2
• Goal is to maintain serum potassium 4-5 mEq/L throughout treatment 2

Rationale: Total body potassium is severely depleted in DKA despite potentially normal or elevated initial levels due to acidosis-induced extracellular shift. Insulin therapy drives potassium intracellularly, risking life-threatening hypokalemia 1, 2.

Phosphate Replacement

• Phosphate is included in potassium replacement as 1/3 KPO4 1, 2
• No additional phosphate supplementation is typically required 1

Bicarbonate Therapy

• Do not administer bicarbonate unless pH <6.9 1, 2
• Multiple studies demonstrate no benefit in DKA resolution or time to discharge with bicarbonate therapy 1, 2

Monitoring During Treatment

Frequency of Laboratory Assessment

• Monitor blood glucose, electrolytes, BUN, creatinine, venous pH, and β-hydroxybutyrate every 2-4 hours 2
• After initial arterial blood gas, venous pH adequately monitors acidosis resolution (venous pH typically 0.03 units lower than arterial) 2
• Calculate anion gap with each laboratory draw to track acidosis resolution 2

Critical pitfall: Avoid repeated arterial blood gas sampling—venous pH and anion gap suffice for monitoring after initial diagnosis 2.

Clinical Monitoring

• Assess hemodynamic status, fluid input/output, and mental status continuously 1
• Monitor for signs of cerebral edema, particularly if mental status deteriorates during treatment 2

Resolution Criteria

DKA is resolved when ALL of the following criteria are met: 2, 3

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

Continue monitoring β-hydroxybutyrate until it normalizes, as ketonemia typically takes longer to clear than hyperglycemia 1, 2.

Transition to Subcutaneous Insulin

Timing and Method

• Administer basal subcutaneous insulin (NPH, detemir, glargine, or degludec) 2-4 hours before stopping IV insulin infusion 1, 2, 3
• This overlap prevents rebound hyperglycemia and recurrent ketoacidosis 2, 3

Dosing Strategy

• Calculate total daily dose based on patient's pre-admission regimen or estimate 0.5-0.8 units/kg/day 1
• Provide 50% as basal insulin and 50% as prandial rapid-acting insulin divided before meals 1
• Include correction scale insulin for hyperglycemia 1

Critical pitfall: Stopping IV insulin without prior subcutaneous basal insulin administration leads to recurrent ketoacidosis, as the therapeutic effect of subcutaneous insulin is delayed 2, 3.

Special Considerations

Euglycemic DKA

• If glucose is <250 mg/dL at presentation or falls rapidly, immediately add dextrose 5-10% to IV fluids while continuing insulin infusion 2, 3
• This scenario occurs with SGLT2 inhibitor use, prolonged fasting, pregnancy, or alcohol use 3, 5
• Never stop insulin based on glucose levels alone—continue until all resolution criteria are met 2, 3

Mild to Moderate DKA

• Patients who are alert and not severely dehydrated may be treated with subcutaneous rapid-acting insulin analogs in the emergency department or step-down units 1
• This approach requires adequate nurse training, frequent bedside glucose testing, and appropriate follow-up 1
• However, continuous IV insulin remains the standard of care for critically ill or mentally obtunded patients 1, 2

Treatment of Underlying Cause

• Concurrently treat any precipitating infection with appropriate antibiotics 1, 2
• Address medication non-adherence, provide diabetes education, and arrange close follow-up to prevent recurrence 1, 2

Discharge Planning

• Ensure structured discharge plan including diabetes education on DKA recognition, prevention, and sick-day management 1, 2
• Verify adequate outpatient insulin supply and follow-up appointments 1
• Consider social factors contributing to DKA (insulin access, financial constraints) and provide appropriate resources 5