Harvey's Garden

Hyperglycemic crises

3 min read

Epidemiology

Etiology

Pathophysiology

DKA

Intracellular potassium deficit

  • As a result of hyperglycemic hyperosmolality, potassium shifts along with water from inside cells to the extracellular space and is lost in the urine.
  • Insulin normally promotes cellular potassium uptake but is absent in DKA, compounding the problem.
  • A total body potassium deficit develops in the body, although serum potassium may be normal or even paradoxically elevated.
  • Insulin deficiency → hyperosmolality → K+ shift out of cells + lack of insulin to promote K+ uptake → intracellular K+ depleted → total body K+ deficit despite normal or even elevated serum K+

Tip

There is a total body potassium deficit in DKA. This becomes important during treatment, when insulin replacement leads to rapid potassium uptake by depleted cells and patients may require potassium replacement.

HHS

  • Primarily affects patients with type 2 diabetes
  • The pathophysiology of HHS is similar to that of DKA.
  • However, in HHS, there are still small amounts of insulin being secreted by the pancreas, and this is sufficient to prevent DKA by suppressing lipolysis and, in turn, ketogenesis.
  • HHS is characterized by symptoms of marked dehydration (and loss of electrolytes) due to the predominating hyperglycemia and osmotic diuresis.

Clinical features

Diagnostics

Tip

  • DKA is the diagnosis in patients with type 1 diabetes who have hyperglycemia, ketonuria, and high anion gap metabolic acidosis with decreased bicarbonate!
  • HHS is the diagnosis in patients with type 2 diabetes who have hyperglycemia and hyperosmolality!

Electrolytes and renal function

  • Sodium:
    • Hyponatremia is common in both DKA and HHS, due to hypovolemic hyponatremia and hypertonic hyponatremia
      • Uncontrolled high blood sugar (hyperglycemia) in DKA acts like a magnet for water.
      • This extra sugar in the blood pulls water out of cells, causing them to shrink.
      • While the total body water stays the same, the concentration of sodium in the remaining extracellular fluid (outside the cells) gets diluted.
    • Always check corrected sodium for hyperglycemia.
  • Potassium in DKA: normal or elevated (despite a total body deficit)

Treatment

  1. IV Fluids (IVF) - Highest Priority
    • Start immediately with 0.9% Normal Saline (NS), 1-1.5 L in the first hour.
    • Once blood glucose (BG) is ~200-250 mg/dL, switch IVF to D5W in 0.45% NS to prevent hypoglycemia and cerebral edema.
  2. Potassium (K+) - Check Before Insulin
    • Crucial: Patients have a total body K+ deficit.
    • If K+ is <3.3 mEq/L: HOLD INSULIN. Give K+ first to prevent fatal arrhythmia.
    • If K+ is ≥3.3 mEq/L: Give K+ (20-40 mEq/L) along with IVF and insulin.
  3. Insulin - After Fluids & K+ Check
    • Start a continuous IV infusion of Regular Insulin at 0.1 U/kg/hr.
    • Goal in DKA: Continue insulin until the anion gap is closed. This is more important than the BG level.

Graph View

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