Diabetic ketoacidosis

Background

  • Hyperglycemia
    • Leads to osmotic diuresis
      • Loss of fluid, Na, Cl, K, Phos, Ca, Mg
  • Acidosis
    • Due to lipolysis / accumulation of of ketoacids (represented by anion gap showing conjugate bases)
    • Compensatory respiratory alkalosis
    • Breakdown of adipose > prostaglandin I2, E2
      • Prostaglandins + acidosis = vasodilation
      • Prostaglandins cause N/V/abd pain
  • Dehydration
    • Causes Renin system activation
      • K and ketoanion loss (in exchange for chloride)
        • Worsens metabolic acidosis

Causes

Workup

  • CBC
  • Chem 10
  • UA
  • Serum ketones: Beta-hydroxybutrate, acetoacetate
  • hCG
  • ECG
  • VBG (often dose not change management unless suspect inadequate respiratory compensation)
    • Venous pH ~ 0.03 lower than arterial pH
    • Verify that respiratory compensation is as expected
  • CXR

Diagnosis

  • Diagnosis = BS >250, AG >10, bicarb <15, pH <7.3, mod ketones
    • BS may be lower if impaired gluconeogenesis (liver failure)
    • Bicarb may be normal if concurrent alkalosis (e.g. vomiting)
      • In this case an elevated gap may be the only clue
  • Severity
    • Mild (ketosis): gap <12
    • Mod: gap 12-18
    • Severe: gap >18

Treatment

  • Volume then potassium then insulin

Labs/Monitoring

  • Glucose check Q1hr
  • Chem 10 Q4hr (initially Q2hr)
  • Check pH prn based on clinical status (eval respiratory compensation)
  • Check appropriateness of insulin dose Q1hr (see below)
  • Corrected Na:
    • Add 1.6 for each glucose of 100 >100

Fluids

  • Most pts 3-6L depleted
  • If severe hypovolemia: 1L NS/hr for up to 3 hr
  • If mild dehydration then evaluate corrected Na+
  • When BS < 250 switch to D51/2NS@ 150-200 ml/hr(+/- KCl)
  • Bolus NS as needed for unstable VS

Insulin

  • Check K prior to insulin Tx!
    • If K < 3.3 do not administer insulin
  • IV Route
    • IV gtt 0.1 U/kg/hr
      • Bolus dose unnecessary
    • Expect BS fall by 50-100 mg/dL per hr
      • If BS, pH, AG not improving after adequate hydration and UOP, then double infusion rate Q1hr until achieved
      • Refractoriness often due to infection
    • When BS <200, reduce to 0.02-0.05 U/kg/hr IV OR give subQ 0.1 U/kg q2hr
      • Maintain BS between 150 and 200 until resolution of DKA
      • Continue IV infusion for 1-2 hr after SC insulin tx is begun
  • SubQ route (appropriate only for mild DKA)
    • Insulin lispro or aspart 0.3 U/kg initially
      • 0.2 U/kg one hr later
        • 0.2 U/kg q2hr thereafter
    • If BS does not decrease by 50-100/hr then double dose qhr until achieved
  • Pitfalls
  • Do not stop insulin infusion until AG normalized AND bicarb normalized
  • Excess Cl from NS bolus' artificially raises serum Cl 

Potassium

  • Ensure adequate urine output before giving K
  • Prevent Hypokalemia
  • >5.5: don't give, but recheck q2hr
  • 3.3-5.5: give 30 meq/hr in each liter bag
    • 1/2NS is preferred b/c adding 30meq to NS = hypertonic soln
  • <3.3: hold insulin and give 30 meq/hr until K >3.3

Bicarb

  • Consider for pH <6.9 AND:
    • Decreased contractility
    • Hypotension
    • Severe Hyperkalemia
    • Coma
  • 100 meq NaHCO3 in 400mL H2O @ 200 mL/hr
    • Dose as needed until pH > 7.00

Phosphate

  • Hypophosphatemia following insulin tx usually asymptomatic
  • Consider repletion (KPO4 20-30 meq/L)if:
    • Phosphate <1.0
    • Cardiac dysfunction
    • Respiratory dysfunction
    • Evidence of hemolysis or rhabdo


DKA Refractory to Treatment

Ketoacidosis/ AG persists & BG 70 to 150 mg/dL:

  • Start D10W or D10NS @ 150 - 250 mL/h and/or consider reducing insulin rate by 1/2.
    • Keep Serum glucose between 150 – 200 mg/dL

Ketoacidosis/ AG persists & BG < 70 mg/dL:

  • Hold insulin X 15 min and Bolus 1 AMP D50 IVP
  • Recheck FS BG if < 70, retreat w/ 1 AMP D50 IVP and repeat FS BG
  • Once FS BG > 70 mg/dL, restart Insulin @ 1⁄2 prior infusion rate
  • Start D10W or D10NS (If volume depleted)@ 150 - 250 mL/h


  • Keep Serum glucose between 150 –200 mg/dL
  • If cannot maintain glucose > 150 mg/dL despite D10 and diet then titrate insulin down to a minimum of 0.5 unit/hr

Complications

  • Cerebral Edema
    • Almost all affected pts are <20yr
    • Associated with initial bicarb level; not rate of glucose drop
    • Premonitory symptoms:
    • Treatment
      • Mannitol IV 1-2gm/kg OR
      • 3% NS 5-10mL/kg over 30min
  • Noncardiogenic pulmonary edema

Sliding Scale

  • 200-250 = 4u sq
  • 251-300 = 6
  • 301-350 = 8
  • 351-400 = 10

Treatment Algorithm

ADA DKA.gif

See Also

Source

  • Tintinalli's
  • UpToDate
  • EBmedicine.net

Image: UpToDate

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