How do you differentiate between mild, moderate, and severe Diabetic Ketoacidosis (DKA)?

Differentiation of Mild, Moderate, and Severe Diabetic Ketoacidosis (DKA)

DKA severity is primarily categorized based on the degree of acidosis, with mild DKA defined as venous pH 7.25-7.30 and bicarbonate 15-18 mmol/L, moderate DKA as pH 7.00-7.24 and bicarbonate 10-15 mmol/L, and severe DKA as pH <7.00 and bicarbonate <10 mmol/L. 1

Diagnostic Parameters for DKA Classification

• Mild DKA:

  • Venous pH: 7.25-7.30 1
  • Serum bicarbonate: 15-18 mEq/L 1
  • Mental status: Alert 1
  • Typically resolves more quickly, with 46% resolving within 4 hours and 69% within 6 hours 2

• Moderate DKA:

  • Venous pH: 7.00-7.24 1
  • Serum bicarbonate: 10-15 mEq/L 1
  • Mental status: Drowsy 1
  • Longer resolution time compared to mild DKA 2

• Severe DKA:

  • Venous pH: <7.00 3, 1
  • Serum bicarbonate: <10 mEq/L 3, 1
  • Mental status: Stupor/coma 1
  • Only 5% resolve within 4 hours and 11% within 6 hours 2
  • Associated with higher morbidity and mortality 3
  • Often requires more intensive monitoring including central venous and intra-arterial pressure monitoring 3

Essential Laboratory Evaluation

• Complete metabolic panel, venous blood gases, complete blood count, urinalysis, and serum ketones should be obtained immediately upon presentation 1
• Calculate anion gap using the formula [Na⁺] - ([Cl⁻] + [HCO₃⁻]) to assess severity of metabolic acidosis 1
• Direct measurement of β-hydroxybutyrate (β-OHB) in blood is preferred over urine ketones for diagnosis and monitoring 1, 4
• Corrected sodium should be calculated using the formula: [measured Na (mEq/L)] + [glucose (mg/dL) - 100]/100 × 1.6 1

Important Clinical Considerations

• A pH cutoff value of 7.13 has been identified as predictive of resolution time >12 hours (sensitivity 77%, specificity 88%) 5
• Patients with pH <7.13 are 3.3 times more likely to have prolonged resolution time 5
• Traditional DKA criteria include blood glucose >250 mg/dL, but be aware that euglycemic DKA can occur, especially in patients taking SGLT2 inhibitors 6
• DKA can present with alkalemia (pH >7.4) in 23.3% of cases due to mixed acid-base disorders, termed "diabetic ketoalkalosis" 7

Monitoring During Treatment

• Blood should be drawn every 2-4 hours to measure electrolytes, glucose, BUN, creatinine, osmolality, and venous pH 1, 4
• Follow venous pH and anion gap to monitor resolution of acidosis 4
• Ketonemia typically takes longer to clear than hyperglycemia, requiring continued monitoring 1, 4

Resolution Criteria

• Glucose <200 mg/dL 4
• Serum bicarbonate ≥18 mEq/L 4
• Venous pH >7.3 4
• Anion gap ≤12 mEq/L 4

Common Pitfalls to Avoid

• Relying solely on urine ketones for diagnosis or monitoring response to treatment 1, 4
• Discontinuing insulin therapy prematurely before ketoacidosis resolves 4
• Failing to add dextrose when glucose falls below 250 mg/dL while continuing insulin therapy 4
• Inadequate monitoring of electrolytes, particularly potassium 1, 4
• Missing diabetic ketoalkalosis cases where pH is >7.3 but significant ketosis is present 7