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

Diagnostic Criteria and Initial Management for Diabetic Ketoacidosis (DKA)

The diagnostic criteria for DKA include blood glucose >250 mg/dL, venous pH <7.3, serum bicarbonate <15 mEq/L, and moderate ketonuria or ketonemia. 1

Diagnostic Criteria

• Blood glucose >250 mg/dL - Hyperglycemia is a fundamental component of classic DKA diagnosis 1
• Venous pH <7.3 - Indicates the severity of acidosis 1
• Serum bicarbonate <15 mEq/L - Reflects metabolic acidosis 1
• Moderate ketonuria or ketonemia - Essential for confirming ketosis 1

Severity Classification

• Mild DKA: Venous pH 7.25-7.30, bicarbonate 15-18 mEq/L, alert mental status 1
• Moderate DKA: Venous pH 7.00-7.24, bicarbonate 10-15 mEq/L, drowsy mental status 1
• Severe DKA: Venous pH <7.00, bicarbonate <10 mEq/L, stupor/coma, higher risk of complications 1

Initial Laboratory Evaluation

• Obtain complete metabolic panel, venous blood gases, complete blood count, urinalysis, and serum ketones immediately 1
• Calculate anion gap using the formula [Na⁺] - ([Cl⁻] + [HCO₃⁻]) 1
• Correct serum sodium for hyperglycemia using the formula: [measured Na (mEq/L)] + [glucose (mg/dL) - 100]/100 × 1.6 1
• Direct measurement of β-hydroxybutyrate (β-OHB) in blood is preferred over nitroprusside method 1
• Obtain bacterial cultures of urine, blood, and throat if infection is suspected 2

Initial Management

Fluid Therapy

• Begin aggressive fluid resuscitation with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (1-1.5 L in average adult during first hour) to restore circulatory volume and tissue perfusion 2, 3
• Subsequent fluid choice depends on hydration state, serum electrolytes, and urine output 2
• When serum glucose reaches 250 mg/dL, change fluid to 5% dextrose with 0.45-0.75% NaCl while continuing insulin therapy 4

Insulin Therapy

• Start continuous intravenous insulin infusion at 0.1 units/kg/hour until resolution of ketoacidosis, regardless of glucose levels 3
• Continue insulin infusion even when glucose falls below 250 mg/dL by adding dextrose to hydrating solution 4
• Target glucose between 150-200 mg/dL until DKA resolution 4

Electrolyte Management

• Monitor potassium levels closely as insulin administration can cause hypokalemia 4
• Once renal function is assured, include 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO₄) in IV fluids until patient can tolerate oral supplementation 2
• Maintain serum potassium between 4-5 mmol/L 4

Monitoring During Treatment

• Draw blood 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
• Monitor for signs of cerebral edema, especially in pediatric patients 5

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 treatment response (nitroprusside method doesn't measure β-OHB) 1
• Discontinuing insulin therapy prematurely before ketoacidosis resolves 4
• Inadequate monitoring of electrolytes, particularly potassium 1
• Overzealous treatment with insulin without glucose supplementation can lead to hypoglycemia 4
• Interruption of insulin infusion is a common cause of persistent or worsening ketoacidosis 4

Special Considerations

• Euglycemic DKA can occur with serum glucose <250 mg/dL with anion gap metabolic acidosis and ketosis, especially in patients using SGLT2 inhibitors 6
• Diabetic ketoalkalosis (pH >7.4) can occur due to mixed acid-base disorders but still requires the same treatment as traditional DKA 7
• Identify and treat precipitating factors such as infection, insulin omission, or myocardial infarction 5