Diabetic ketoacidosis

Definition

• An anion gap acidosis caused by an accumulation of ketone bodies secondary to severe insulin deficiency

Etiology

• Missed insulin (most common cause)

Pathophysiology

• Severe insulin deficiency causes the body to be unable to process glucose for energy, so instead relies on increased fatty acid metabolism, resulting in an accumulation of ketone bodies
• Hyperglycemia creates an osmotic diuresis which causes dehydration
• Insulin deficiency also causes a potassium shift from intra- to extracellular space, combined with the diuresis causes total body potassium depletion

Differential Diagnosis

• DKA
• Hyperglycemia
• Hyperosmolar hyperglycemic state (HHS/HONK)

Risk Factors

• Preexisting diagnosis of T1DM

Clinical Manifestations

• History
  • Thirst/polyuria
  • Nausea/vomiting/abdominal pain
  • Weakness/malaise
  • Change in mental status
• Exam
  • Altered mental status
  • Kussmaul respiration
  • Fever
  • Acetone on breath

Investigations

• Glucose q1h
• SMA7 and VBG q2-4h

Management

• Fluid resuscitation (most important)
  • Aggressive fluid resuscitation is the best treatment for hyperglycemia
  • Usually require 6-10L in first 24 hours
• Insulin therapy treats the ketoacidosis, so don't stop until anion gap resolves
  • 0.1-0.2 units/kg/h (6-10 U/kg/h on average)
  • Titrate based on anion gap and hyperglycemia
• Potassium supplementation: patients lose about 5mEq/kg when in DKA
  • If initial K <3.3, must replace potassium before starting insulin
  • Supplement to keep K between 4-5
• Sodium bicarb: consider adding when pH<6.8 or in respiratory failure
• Treat the underlying cause
• Change to subcutaneous insulin when glucose < 15, anion gap resolved (x12+ hours), and patient willing to eat
  • Calculate total daily dose from IV rate x 24h, then give that dose as detemir/glargine twice daily (new TDD is twice the IV TDD)
  • Overlap with insulin running at half current rae for 6-8 hours after basal insulin

Memphis Insulin Protocol

• IV fluids:
  • NS at 500-1000 mL/h for 2 h
  • 1/2 NS at 250-500 mL/h until glucose <13.8 mmol/L
  • D5w-1/2 NS at 150-250 mL/h until resolution of DKA, targetting gluoce of 11.1 mmol/L
• Potassium
  • K > 5.5: check serum K every 2 hours
  • K 4-5.5: add 20 mmol KCL/L
  • K 3-4: add 40 mmol KCl/L
  • K ≤3: give 10-20 mmol KCl hourly until serum K over 3, then add 40 KCl mmol/L
• Insulin
  • Insulin aspart hourly
    • Loading dose 0.3 units/kg SC once, followed by
    • 0.1 units/kg SC q1h until glucose <13.8, then
    • 0.05 units/kg SC q1h until resolution of DKA
  • Insulin aspart every 2 hours
    • Loading dose 0.3 units/kg SC once, followed one hour later by
    • 0.2 units SC q2h until glucose <13.8, then
    • 0.1 units SC q2h until resolution of DKA
  • IV regular insulin
    • Bolus 0.1 units/kg IV once, followed by
    • Continuous infusion of 0.1 units/kg/h until glucose <13.8, then
    • Continuous infusion of 0.05 units/kg/h until resolution of DKA
• Laboratory
  • Admission: CBC, complete metabolic panel, venous pH, serum beta-hydroxybutyrate
  • BMP, venous pH, phosphorus, and beta-hydroxybutyrate every 2 horus x2 then every 4 hours until resolution of DKA
  • Point-of-care glucose fingerstick every 1-2 hours