What is the next best step for a patient with diabetic ketoacidosis and hyperglycemia after initial insulin and Lantus (insulin glargine) treatment?

Management of Diabetic Ketoacidosis with Paradoxical Hyperglycemia After Initial Treatment

Stop the current insulin regimen immediately and reassess the patient's DKA status, fluid resuscitation, and electrolytes—particularly potassium—before escalating insulin therapy. The rising glucose from 180 mg/dL to 286 mg/dL after insulin administration is concerning and suggests either inadequate fluid resuscitation, severe insulin resistance, electrolyte abnormalities (especially hypokalemia), or that the patient remains in active DKA requiring continuous IV insulin infusion rather than subcutaneous insulin.

Critical Assessment Steps

First, verify potassium levels immediately. If potassium is <3.3 mEq/L, insulin must be held and potassium replaced first, as insulin drives potassium intracellularly and can precipitate life-threatening hypokalemia 1. Severe hypokalemia (<2.5 mEq/L) is associated with increased inpatient mortality in hyperglycemic crises 2.

Second, confirm adequate fluid resuscitation. Dehydration impairs insulin effectiveness 1. The patient should be receiving 0.9% NaCl or other crystalloid at a rate aiming to replace 50% of estimated fluid deficit in the first 8-12 hours 1. Inadequate hydration is a common reason for poor glucose response to insulin.

Third, determine if the patient is still in DKA. Check venous pH, bicarbonate, and ketones (preferably β-hydroxybutyrate) 1, 3. DKA is defined by glucose >250 mg/dL, pH <7.3, bicarbonate <15 mEq/L, and positive ketones 1. If DKA persists, the patient requires continuous IV insulin infusion, not subcutaneous insulin 2.

Appropriate Insulin Management for Active DKA

If DKA is confirmed, transition to continuous IV regular insulin infusion. The standard protocol is an IV bolus of 0.15 units/kg followed by continuous infusion at 0.1 units/kg/hour (approximately 5-7 units/hour in adults) 1, 3. The glucose should decrease by 50-75 mg/dL in the first hour 1.

If glucose is not falling adequately after one hour on IV insulin:

• Verify hydration status is acceptable 1
• Double the insulin infusion rate hourly until achieving steady glucose decline of 50-75 mg/dL per hour 1
• Monitor glucose every 1-2 hours until stable 3

When glucose reaches 250 mg/dL, do not stop insulin. Instead, decrease the infusion to 0.05-0.1 units/kg/hour and add dextrose 5-10% to IV fluids to prevent hypoglycemia while continuing to correct ketosis 1. This is a critical pitfall—stopping insulin when glucose normalizes allows ketoacidosis to persist.

Monitoring Requirements

Draw blood every 2-4 hours for:

• Serum electrolytes (especially potassium)
• Glucose
• BUN and creatinine
• Osmolality
• Venous pH 1, 3

Venous pH is adequate for monitoring (typically 0.03 units lower than arterial pH), and repeat arterial blood gases are generally unnecessary 1.

Common Pitfalls in This Case

The use of subcutaneous Lantus (glargine) 14 units in active DKA is inappropriate. Subcutaneous insulin is unpredictably absorbed in dehydrated, acidotic patients and cannot be titrated rapidly 2. Continuous IV insulin infusion is the standard of care for moderate-to-severe DKA 2.

The "GI drip" (10 units regular insulin in DNS) is suboptimal. This provides neither adequate insulin delivery rate nor appropriate fluid resuscitation. DKA requires separate, controlled insulin infusion and aggressive crystalloid resuscitation 2, 1.

Do not rely on glucose normalization alone as a marker of DKA resolution. Resolution requires glucose <200 mg/dL, bicarbonate ≥18 mEq/L, AND pH ≥7.3 3. Premature discontinuation of IV insulin based on glucose alone leads to rebound ketoacidosis.

Transition to Subcutaneous Insulin

Only transition to subcutaneous insulin after metabolic stability is achieved:

• Glucose <200 mg/dL
• Bicarbonate ≥18 mEq/L
• pH ≥7.3
• Patient able to eat 3, 2

When transitioning, provide 1-2 hours overlap between IV and subcutaneous insulin to prevent rebound hyperglycemia 1. Initiate a basal-bolus regimen with long-acting insulin (glargine) once daily and rapid-acting insulin (glulisine, lispro, or aspart) before meals 2, 4. This approach results in lower hypoglycemia rates than NPH/regular insulin regimens 4.

Calculate subcutaneous insulin dose from the average insulin infused during the 12 hours before transition. For example, if averaging 1.5 units/hour, the estimated daily dose is 36 units/24 hours, typically split as 50% basal and 50% prandial insulin 2.