What is the treatment for a patient with large ketones in their urine, indicating diabetic ketoacidosis (DKA)?

Treatment of Diabetic Ketoacidosis (DKA) with Large Urinary Ketones

For a patient with large ketones in urine indicating diabetic ketoacidosis, treatment should include immediate intravenous insulin infusion, aggressive fluid resuscitation, and electrolyte replacement, with regular monitoring of glucose and electrolytes every 2-4 hours until resolution. 1

Initial Assessment and Diagnosis

• Confirm DKA diagnosis with:

  • Blood glucose >250 mg/dL
  • Arterial pH <7.3
  • Bicarbonate <15 mEq/L
  • Presence of ketones in urine or blood 1

• Obtain immediately:

  • Complete blood count
  • Blood glucose
  • Electrolytes, BUN, creatinine
  • Venous pH (can substitute for arterial blood gases)
  • Urinalysis
  • Calculate anion gap 1

Treatment Algorithm

1. Fluid Replacement

• Adult patients:

  • Initial: Normal saline (0.9% NaCl) at 15-20 mL/kg/hr during first hour (typically 1-1.5 L)
  • Subsequent: 0.45-0.9% NaCl at 4-14 mL/kg/hr depending on hydration status
  • When glucose reaches 200 mg/dL, change to 5% dextrose with 0.45% saline 1

• Pediatric patients (<20 years):

  • Initial: 0.9% NaCl at 10-20 mL/kg/hr for first hour (not exceeding 50 mL/kg in first 4 hours)
  • Subsequent: 0.45-0.9% NaCl at 1.5 times maintenance requirements 1

2. Insulin Therapy

• For moderate to severe DKA:

  • Exclude hypokalemia (K+ <3.3 mEq/L) before starting insulin
  • Administer IV bolus of regular insulin at 0.15 units/kg body weight
  • Follow with continuous IV infusion at 0.1 unit/kg/hr (typically 5-7 units/hr in adults) 1
  • If glucose doesn't fall by 50 mg/dL in first hour, double insulin infusion rate hourly until achieving steady glucose decline of 50-75 mg/hr 1

• For mild DKA:

  • Can use subcutaneous or intramuscular regular insulin
  • Initial "priming" dose of 0.4-0.6 units/kg (half IV bolus, half subcutaneous)
  • Then 0.1 unit/kg/hr subcutaneously 1
  • For adults: 5-unit increments for every 50 mg/dL increase in blood glucose above 150 mg/dL (up to 20 units for blood glucose of 300 mg/dL) 1

3. Potassium Replacement

• Begin potassium replacement when serum levels fall below 5.5 mEq/L (assuming adequate urine output)
• Add 20-30 mEq potassium (2/3 KCl and 1/3 KPO₄) per liter of IV fluid 1
• If initial potassium is <3.3 mEq/L, start potassium replacement before insulin therapy 1

4. Bicarbonate Therapy

• Generally not recommended if pH >7.0 1
• For pH 6.9-7.0: 50 mmol sodium bicarbonate diluted in 200 mL sterile water, infused at 200 mL/hr 1
• For pH <6.9: 100 mmol sodium bicarbonate in 400 mL sterile water at 200 mL/hr 1

5. Phosphate Replacement

• Routine phosphate replacement not necessary
• Consider only for patients with cardiac dysfunction, anemia, respiratory depression, or serum phosphate <1.0 mg/dL 1

Monitoring and Transition

• Monitor blood glucose and electrolytes every 2-4 hours 1

• Follow venous pH and anion gap to monitor resolution of acidosis 1

• Criteria for DKA resolution:

  • Glucose <200 mg/dL
  • Serum bicarbonate ≥18 mEq/L
  • Venous pH >7.3 1

• When DKA resolves and patient can eat:

  • Transition to subcutaneous insulin regimen
  • Continue IV insulin for 1-2 hours after starting subcutaneous insulin to prevent rebound hyperglycemia 1
  • Start multiple-dose schedule using combination of short/rapid-acting and intermediate/long-acting insulin 1

Common Pitfalls to Avoid

1. Relying on urine ketone measurements: Nitroprusside method only measures acetoacetic acid and acetone, not β-hydroxybutyrate (the predominant ketone in DKA). During treatment, β-hydroxybutyrate converts to acetoacetic acid, potentially making ketosis appear worse 1

2. Inadequate potassium replacement: Despite hyperkalemia at presentation, total body potassium is depleted. Insulin therapy will drive potassium intracellularly, potentially causing dangerous hypokalemia 1

3. Abrupt discontinuation of IV insulin: Always overlap IV and subcutaneous insulin administration by 1-2 hours to prevent rebound hyperglycemia 1

4. Excessive fluid administration: Especially in pediatric patients, can lead to cerebral edema 1

5. Overuse of bicarbonate: Studies have shown no benefit in most cases and may potentially cause harm 1

6. Failure to identify and treat precipitating causes: Infections, myocardial infarction, stroke, or medication non-compliance must be addressed 1

7. Inadequate monitoring: Regular assessment of glucose, electrolytes, and acid-base status is essential for safe management 1

By following this structured approach to DKA management, mortality can be significantly reduced and complications minimized.