What are the diagnosis and treatment guidelines for a patient presenting with diabetic ketoacidosis (DKA)?

Diabetic Ketoacidosis: Diagnosis and Treatment

Diagnostic Criteria

DKA is diagnosed when all three criteria are present: blood glucose >250 mg/dL (though euglycemic DKA can occur with SGLT2 inhibitors), arterial pH <7.3, serum bicarbonate <15 mEq/L, and presence of ketonemia or ketonuria. 1

Essential Laboratory Workup

• Obtain 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 1, 2
• Direct measurement of β-hydroxybutyrate in blood is the preferred method for diagnosis and monitoring—the nitroprusside method only detects acetoacetic acid and acetone, missing the predominant ketone body 1, 2
• Obtain bacterial cultures (urine, blood, throat) if infection is suspected as a precipitating factor 1
• Chest X-ray should be obtained if clinically indicated 3

DKA Resolution Criteria (All Must Be Met)

• Glucose <200 mg/dL 1, 2
• Serum bicarbonate ≥18 mEq/L 1, 2
• Venous pH >7.3 1, 2
• Anion gap ≤12 mEq/L 1, 2

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Initial Management: The Critical First Hour

Fluid Resuscitation

Begin with isotonic saline (0.9% NaCl) at 15-20 mL/kg/hour (approximately 1-1.5 L in average adult) during the first hour to restore intravascular volume and renal perfusion. 1, 2

• After the first hour, switch to 0.45% NaCl at 4-14 mL/kg/hour if corrected serum sodium is normal or elevated 2
• Continue 0.9% NaCl at similar rate if corrected serum sodium is low 2
• When glucose reaches 200-250 mg/dL, switch to 5% dextrose with 0.45-0.75% saline while continuing insulin infusion—this prevents hypoglycemia while allowing complete ketoacidosis resolution 1, 2

Critical Potassium Management Before Insulin

Do NOT start insulin if serum potassium is <3.3 mEq/L—this is an absolute contraindication that can cause life-threatening cardiac arrhythmias and death. 1

• If K+ <3.3 mEq/L: Delay insulin therapy and aggressively replace potassium with 20-40 mEq/L in IV fluids until K+ ≥3.3 mEq/L 3
• If K+ 3.3-5.5 mEq/L: Add 20-30 mEq/L potassium to IV fluids (use 2/3 KCl and 1/3 KPO₄) once adequate urine output is confirmed 1, 2
• If K+ >5.5 mEq/L: Withhold potassium initially but monitor closely every 2-4 hours, as levels will drop rapidly with insulin therapy 1
• Target serum potassium of 4-5 mEq/L throughout treatment—total body potassium depletion averages 3-5 mEq/kg despite normal or elevated initial levels 1

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Insulin Therapy Protocol

Standard IV Insulin for Moderate-Severe DKA

For critically ill, mentally obtunded patients, or moderate-severe DKA: Give IV bolus of 0.1 units/kg regular insulin, followed by continuous infusion at 0.1 units/kg/hour. 3, 1

• Target glucose decline of 50-75 mg/dL per hour 3, 1
• If glucose does not fall by 50 mg/dL in the first hour, verify adequate hydration status, then double the insulin infusion rate every hour until achieving steady decline of 50-75 mg/dL/hour 1
• Continue insulin infusion until ALL resolution criteria are met, regardless of glucose levels—stopping insulin prematurely when glucose normalizes is a common error that leads to persistent ketoacidosis 1, 2

Alternative Approach for Mild-Moderate Uncomplicated DKA

For hemodynamically stable, alert patients with mild-moderate DKA: Subcutaneous rapid-acting insulin analogs at 0.15 units/kg every 2-3 hours combined with aggressive fluid management are equally effective, safer, and more cost-effective than IV insulin. 1

• This approach requires adequate fluid replacement, frequent point-of-care glucose monitoring, and treatment of concurrent infections 1
• Continuous IV insulin remains the standard for critically ill and mentally obtunded patients 1

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Monitoring During Treatment

• Check blood glucose every 2-4 hours 3, 1
• Measure serum electrolytes, glucose, BUN, creatinine, osmolality, and venous pH every 2-4 hours 1, 2
• Follow venous pH (typically 0.03 units lower than arterial pH) and anion gap to monitor resolution of acidosis 1
• Monitor potassium levels closely every 2-4 hours, as insulin drives potassium intracellularly 3, 1

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Bicarbonate: Generally NOT Recommended

Bicarbonate is NOT recommended for DKA patients with pH >6.9-7.0—multiple studies show no difference in resolution of acidosis or time to discharge, and it may worsen ketosis, cause hypokalemia, and increase cerebral edema risk. 1

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Transition to Subcutaneous Insulin: The Critical Overlap

Administer basal insulin (glargine or detemir) 2-4 hours BEFORE stopping the IV insulin infusion—this overlap is essential to prevent recurrence of ketoacidosis and rebound hyperglycemia. 3, 1, 2

Common Pitfall to Avoid

• Stopping IV insulin without prior basal insulin administration is the most common error leading to DKA recurrence 3
• Continue IV insulin for 1-2 hours after subcutaneous insulin is given to allow for absorption 3
• Once the patient can eat, start a multiple-dose schedule using combination of short/rapid-acting and intermediate/long-acting insulin 3, 1

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Treatment of Precipitating Factors

Identify and treat underlying causes concurrently with metabolic correction—common triggers include infection (most common), new diabetes diagnosis, insulin omission, myocardial infarction, stroke, pancreatitis, and SGLT2 inhibitor use. 1

• Administer appropriate antibiotics if infection is suspected 1
• Discontinue SGLT2 inhibitors immediately and do not restart until 3-4 days after metabolic stability is achieved—these medications can precipitate euglycemic DKA 1
• For euglycemic DKA (from SGLT2 inhibitors), continue insulin therapy with dextrose despite normal glucose levels 2

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Special Considerations and Complications

• Consider thromboprophylaxis with enoxaparin due to hypercoagulable state associated with DKA 2
• Monitor closely for cerebral edema, especially in children and adolescents—watch for altered mental status, headache, or neurological deterioration 1
• For patients on glucocorticoid therapy, insulin requirements may be significantly higher 2

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Discharge Planning

• Identify outpatient diabetes care providers before discharge 1
• Educate patients on glucose monitoring, insulin administration, recognition and treatment of hyperglycemia/hypoglycemia, and sick day management 3, 1
• Ensure appropriate insulin regimen is prescribed with attention to medication access and affordability 1
• Schedule follow-up appointments prior to discharge 1