What is the initial assessment and treatment plan for a patient with diabetic ketoacidosis (DKA)?

Assessment and Management of Diabetic Ketoacidosis (DKA)

The initial management of diabetic ketoacidosis requires aggressive fluid resuscitation with isotonic saline, continuous intravenous insulin infusion, electrolyte replacement, identification of precipitating factors, and frequent monitoring of clinical and laboratory parameters until resolution. 1, 2

Initial Assessment

• Diagnostic criteria for DKA: blood glucose >250 mg/dL, arterial pH <7.3, serum bicarbonate <15 mEq/L, and presence of ketonemia or ketonuria 3
• Laboratory evaluation should include plasma glucose, blood urea nitrogen/creatinine, serum ketones, electrolytes (with calculated anion gap), osmolality, urinalysis, urine ketones, arterial blood gases, complete blood count with differential, and electrocardiogram 3, 2
• Obtain bacterial cultures (urine, blood, throat) if infection is suspected and administer appropriate antibiotics 3
• Chest X-ray should be obtained if clinically indicated 2
• Identify potential precipitating factors: infection, cerebrovascular accident, alcohol abuse, pancreatitis, myocardial infarction, trauma, drugs, or insulin discontinuation/inadequacy 3

Treatment Protocol

Fluid Therapy

• Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in the average adult) during the first hour 3, 1
• Subsequent fluid choice depends on hydration status, serum electrolyte levels, and urine output 3
• When serum glucose reaches 250 mg/dL, change fluid to 5% dextrose with 0.45-0.75% NaCl to prevent hypoglycemia while continuing insulin therapy 1
• Total fluid replacement should aim to correct estimated deficits within 24 hours 4

Insulin Therapy

• Start with continuous intravenous regular insulin infusion at 0.1 units/kg/hour (preferred method for moderate to severe DKA) 2, 1
• If plasma glucose does not fall by 50 mg/dL from initial value in the first hour, check hydration status; if acceptable, double the insulin infusion rate every hour until a steady glucose decline of 50-75 mg/h is achieved 4
• Continue insulin infusion until resolution of ketoacidosis (pH >7.3, serum bicarbonate ≥18 mEq/L, and anion gap ≤12 mEq/L) regardless of glucose levels 1, 4
• Do not interrupt or discontinue intravenous insulin therapy when glucose levels fall below 250 mg/dL, as this is a common cause of persistent or worsening ketoacidosis 1

Electrolyte Management

• Include 20-30 mEq/L potassium (2/3 KCl and 1/3 KPO₄) in the infusion once renal function is assured 2
• Monitor potassium levels closely, as insulin administration can cause hypokalemia; maintain serum K⁺ between 4-5 mmol/L 1, 2
• Bicarbonate administration is generally not recommended for DKA patients with pH >7.0 4

Monitoring During Treatment

• Draw blood every 2-4 hours to determine serum electrolytes, glucose, blood urea nitrogen, creatinine, osmolality, and venous pH 1, 2
• Follow venous pH (typically 0.03 units lower than arterial pH) and anion gap to monitor resolution of acidosis 1
• Direct measurement of β-hydroxybutyrate in blood is the preferred method for monitoring DKA, as the nitroprusside method only measures acetoacetic acid and acetone 1, 4
• Remember that ketonemia typically takes longer to clear than hyperglycemia 1

Resolution Parameters

• DKA resolution requires: glucose <200 mg/dL, serum bicarbonate ≥18 mEq/L, venous pH >7.3, and anion gap ≤12 mEq/L 1
• Target glucose between 150-200 mg/dL until DKA resolution parameters are met 1

Transition to Subcutaneous Insulin

• Once DKA is resolved, if the patient is NPO (nothing by mouth), continue intravenous insulin and fluid replacement, and supplement with subcutaneous regular insulin as needed 1
• When the patient is able to eat, start a multiple-dose schedule using a combination of short/rapid-acting and intermediate/long-acting insulin 1, 2
• Continue intravenous insulin infusion for 1-2 hours after starting subcutaneous insulin to ensure adequate plasma insulin levels 1
• For adult patients, give 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

Common Pitfalls to Avoid

• Premature termination of insulin therapy before complete resolution of ketosis can lead to recurrence of DKA 4
• Interruption of insulin infusion when glucose levels fall is a common cause of persistent or worsening ketoacidosis 1
• Failure to add dextrose when glucose falls below 250 mg/dL while continuing insulin therapy 1
• Inadequate monitoring and replacement of electrolytes, particularly potassium 1, 2
• Overzealous treatment with insulin without glucose supplementation can lead to hypoglycemia 1