Treatment of Diabetic Ketoacidosis (DKA)
Begin immediate fluid resuscitation with isotonic saline (0.9% NaCl) at 15-20 ml/kg/hour for the first hour, followed by continuous IV regular insulin at 0.1 units/kg/hour without an initial bolus, while aggressively monitoring and replacing potassium to prevent life-threatening arrhythmias. 1, 2
Initial Diagnostic Workup
Obtain the following laboratory studies immediately upon presentation 1, 2:
- Arterial blood gases (pH, bicarbonate)
- Complete blood count with differential
- Comprehensive metabolic panel (electrolytes, BUN, creatinine, glucose)
- Serum ketones (β-hydroxybutyrate preferred over urine ketones) 1
- Calculated anion gap: [Na+] - ([Cl-] + [HCO3-]) 3
- Serum osmolality: 2[measured Na (mEq/l)] + glucose (mg/dl)/18 3
- Urinalysis with ketones
- Electrocardiogram to assess for cardiac effects of electrolyte abnormalities 2
- Blood and urine cultures if infection suspected 2
DKA diagnostic criteria: Blood glucose >250 mg/dl, arterial pH <7.3, bicarbonate <15 mEq/l, and moderate ketonuria or ketonemia 3, 1
Fluid Resuscitation Protocol
Hour 1: Aggressive Volume Expansion
- Administer isotonic saline (0.9% NaCl) at 15-20 ml/kg/hour (approximately 1-1.5 liters in average adult) 3, 1, 2
- This initial bolus targets intravascular volume expansion and restoration of renal perfusion 3
Subsequent Fluid Management
After the initial hour, adjust fluid choice based on corrected serum sodium 3:
- If corrected sodium is normal or elevated: Use 0.45% NaCl at 4-14 ml/kg/hour 3
- If corrected sodium is low: Continue 0.9% NaCl at 4-14 ml/kg/hour 3
- Correction formula: For each 100 mg/dl glucose >100 mg/dl, add 1.6 mEq to sodium value 3
Target total fluid replacement of approximately 1.5 times the 24-hour maintenance requirements, correcting estimated deficits within 24 hours 1, 2
Typical total body deficits in DKA: Water 6-9 liters, sodium 7-10 mEq/kg, potassium 3-5 mEq/kg, phosphate 5-7 mmol/kg, magnesium 1-2 mEq/kg 3, 1
Insulin Therapy
Critical Potassium Threshold
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. 2 Continue aggressive potassium repletion until K+ ≥3.3 mEq/L before initiating insulin 2
Insulin Initiation
- Start continuous IV regular insulin infusion at 0.1 units/kg/hour without an initial bolus 1, 2
- Target glucose decline of 50-75 mg/dl/hour 2
- Continue insulin therapy until resolution of ketoacidosis, regardless of glucose levels 1, 4
Dextrose Addition
When serum glucose reaches 250 mg/dL, add dextrose 5% to IV fluids while continuing insulin infusion 1. This prevents hypoglycemia while allowing continued ketone clearance, which is the actual therapeutic target 4
For euglycemic DKA (glucose <250 mg/dL at presentation): Immediately add dextrose 5-10% to IV fluids at presentation while continuing insulin infusion 4
Electrolyte Management
Potassium Replacement (Critical Priority)
Total body potassium is severely depleted despite potentially normal or elevated initial serum levels due to acidosis-induced extracellular shift 1, 2. Insulin therapy will drive potassium intracellularly, causing rapid decline 2
Replacement protocol once renal function is assured 3, 1, 2:
- Add 20-30 mEq/L potassium to IV fluids when serum K+ falls below 5.5 mEq/L
- Use combination of 2/3 KCl (or potassium-acetate) and 1/3 KPO4
- Monitor serum potassium every 2-4 hours initially
Phosphate, Magnesium, and Calcium
These electrolytes are also depleted (typical deficits: phosphate 5-7 mEq/kg, magnesium 1-2 mEq/kg, calcium 1-2 mEq/kg) 1, and replacement is included in the potassium protocol above 3, 1
Monitoring During Treatment
Frequent Laboratory Assessment
- Blood glucose: Every 1 hour 1, 2
- Electrolytes, BUN, creatinine, osmolality: Every 2-4 hours until stable 1, 2
- Venous pH and anion gap: Every 2-4 hours to assess resolution of acidosis 1, 2
Clinical Monitoring
- Hemodynamic status (blood pressure, heart rate) 3
- Fluid input/output 1
- Neurological status (assess for cerebral edema, especially in children) 1
- Signs of volume overload, particularly in patients with renal or cardiac compromise 1
Resolution Criteria
DKA is resolved when ALL of the following are met 1, 4:
- Blood glucose <200 mg/dL
- Serum bicarbonate ≥15-18 mEq/L
- Venous pH >7.3
- Anion gap normalized (≤12 mEq/L)
Transition to Subcutaneous Insulin
Administer basal subcutaneous insulin (glargine or detemir) 2-4 hours BEFORE stopping the IV insulin infusion 1, 2. This overlap prevents rebound hyperglycemia and recurrence of ketoacidosis 2
Start a multiple-dose insulin schedule using a combination of short/rapid-acting and intermediate/long-acting insulin once the patient can eat 2
Common Pitfalls to Avoid
Inadequate potassium replacement: This is the most dangerous error, leading to cardiac arrhythmias 1. Monitor closely as insulin drives potassium intracellularly 2
Stopping insulin when glucose normalizes: In euglycemic DKA, this is the most critical error—ketoacidosis will persist or worsen 4. Continue insulin until metabolic acidosis resolves, not until glucose normalizes 1, 4
Stopping IV insulin without prior basal insulin administration: This leads to DKA recurrence 2. Always overlap by 2-4 hours 1, 2
Overly rapid correction: While faster fluid administration (15-20 ml/kg/hour initially) leads to more rapid normalization of anion gap and Pco2 5, it is associated with increased frequency of hyperchloremic acidosis (46.1% vs 35.2% with slower rates) 5
Relying solely on urine ketones: The nitroprusside method only detects acetoacetate and acetone, not β-hydroxybutyrate (the primary ketone body) 4. Measure β-hydroxybutyrate directly 4
Insufficient monitoring: Check electrolytes every 2-4 hours initially to catch rapid changes, especially potassium 1, 2
Special Considerations
SGLT2 Inhibitor Use
Be aware that sodium-glucose cotransporter-2 inhibitors modestly increase the risk of DKA and euglycemic DKA 6, 7. These patients require immediate dextrose addition to fluids 4