What are the diagnostic criteria and initial treatment for Diabetic Ketoacidosis (DKA)?

Diagnostic Criteria and Initial Treatment for Diabetic Ketoacidosis (DKA)

DKA is diagnosed by the triad of hyperglycemia (blood glucose >250 mg/dL), metabolic acidosis (pH <7.3, serum bicarbonate <18 mEq/L, anion gap >10 mEq/L), and elevated serum or urine ketones, with initial treatment requiring aggressive IV fluid resuscitation, insulin therapy, and electrolyte replacement. 1, 2

Diagnostic Criteria

DKA severity is classified according to the following parameters:

Parameter	Mild	Moderate	Severe
Arterial pH	7.25-7.30	7.00-7.24	<7.00
Serum bicarbonate (mEq/L)	15-18	10-14	<10
Mental status	Alert	Alert/drowsy	Stupor/coma

1

Key Diagnostic Tests:

• Blood glucose (typically >250 mg/dL, though euglycemic DKA can occur)
• Serum ketones (preferred) or urine ketones
• Venous pH (<7.3)
• Serum bicarbonate (<18 mEq/L)
• Anion gap (>10 mEq/L)
• Electrolytes, phosphate, BUN, creatinine
• Complete blood count with differential
• A1C
• ECG
• Consider: amylase, lipase, liver enzymes, troponin, blood/urine cultures, chest X-ray 2

Clinical Presentation:

• Polyuria and polydipsia (most common)
• Nausea, vomiting, abdominal pain
• Weight loss, severe fatigue
• Fruity breath odor (acetone)
• Kussmaul breathing (deep, rapid breathing)
• Altered mental status (in moderate to severe cases) 1, 2

Initial Treatment Algorithm

1. Fluid Resuscitation

• Begin with 0.9% saline at 15-20 mL/kg/hr for the first hour
• Adjust rate based on hemodynamic status, hydration state, and electrolyte levels
• Caution: More careful fluid administration in patients with heart failure or renal disease 1

2. Insulin Therapy

• For moderate to severe DKA (pH <7.25):

  • Initial IV bolus: 0.15 units/kg body weight of regular insulin
  • Follow with continuous infusion at 0.1 units/kg/hour (approximately 5-7 units/hour in adults)

• For mild DKA (pH 7.25-7.30):

  • Subcutaneous or intramuscular insulin every hour can be used
  • Initial dose 0.4-0.6 U/kg, followed by 0.1 U/kg/h

• Pediatric patients:

  • No initial bolus recommended
  • Start with continuous infusion at 0.1 unit/kg/hour 1

3. Glucose Monitoring and Adjustment

• Target glucose reduction: 50-75 mg/dL per hour
• If glucose doesn't decrease by at least 50 mg/dL in first hour:
  • Verify hydration status
  • Consider doubling insulin infusion rate every hour until achieving stable decrease
• When glucose reaches 200 mg/dL:
  • Add dextrose to IV fluids (D5 or D10)
  • Continue insulin infusion until acidosis resolves (pH ≥7.3, bicarbonate ≥18 mEq/L) 1, 3

4. Electrolyte Replacement

• Potassium:
  • If K+ <3.3 mEq/L: Hold insulin and give potassium until >3.3 mEq/L
  • If K+ 3.3-5.2 mEq/L: Add 20-30 mEq K+ to each liter of IV fluid
  • If K+ >5.2 mEq/L: No replacement; check frequently
• Phosphate: Replace if <1.0 mg/dL or symptomatic
• Bicarbonate: Generally not recommended unless pH <6.9 or severe cardiovascular compromise 1

5. Monitoring

• Measure glucose, electrolytes, and venous pH every 2-4 hours
• Direct measurement of β-hydroxybutyrate in blood is preferred over nitroprusside method
• Monitor for complications: cerebral edema (especially in pediatric patients), hypoglycemia, hypokalemia 1

Resolution Criteria

DKA is considered resolved when:

• Serum bicarbonate ≥18 mEq/L
• Venous pH ≥7.3
• Anion gap normalized 1

Common Pitfalls to Avoid

1. Discontinuing IV insulin too early - Continue until acidosis resolves, regardless of blood glucose levels 1

2. Failing to identify precipitating causes - Common triggers include:

   • Infections
   • New diagnosis of diabetes
   • Medication non-adherence
   • SGLT-2 inhibitor use
   • Insulin pump failure 1, 2

3. Overlooking euglycemic DKA - Can occur with SGLT-2 inhibitor use; diagnose based on acidosis and ketosis even with normal glucose 1, 2

4. Rapid correction of hyperglycemia - Especially dangerous in pediatric patients due to risk of cerebral edema 1

5. Inadequate transition from IV to subcutaneous insulin - Continue IV insulin for 1-2 hours after starting subcutaneous insulin 1

6. Inappropriate use of bicarbonate - Generally not recommended unless severe acidosis (pH <6.9) 1