Electrolyte management (particularly potassium)

Electrolyte management (particularly potassium)

Electrolyte management (particularly potassium)

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DKA & Potassium - The Great K+ Shift

DKA management in anuric dialysis patients

  • Paradox: Patients have a total body K+ deficit (due to osmotic diuresis) but often present with normal or high serum K+ ($hyperkalemia$). This is a critical extracellular shift.

  • Core Pathophysiology: Two main drivers pull K+ out of cells:

    • Insulin Deficiency: Insulin normally stimulates the $Na^+/K^+$-ATPase pump, pushing K+ intracellularly. Its absence traps K+ in the serum.
    • Acidosis: Excess serum $H^+$ ions are exchanged for intracellular K+ via the $H^+/K^+$ anti-porter to buffer the acid, further raising serum K+.

⭐ For every 0.1 unit decrease in blood pH, serum potassium is expected to increase by approximately 0.6 mEq/L.

Potassium Triage - The Crucial First Look

Insulin drives potassium into cells, which can dangerously worsen hypokalemia. Always check serum potassium before starting insulin therapy. The initial K+ level dictates the first step in management.

Total Body Potassium Depletion: Despite normal or even high initial serum K+ levels, all patients with DKA have a significant total body potassium deficit due to urinary losses from osmotic diuresis.

Repletion Roadmap - The K+ Correction Plan

  • Goal: Maintain serum K+ in the target range of 4.0-5.0 mEq/L. Insulin drives K+ intracellularly, so proactive repletion is key.
  • If Serum K+ > 5.2 mEq/L:
    • Start insulin; do not give K+ initially.
    • Recheck serum K+ every 2 hours.
  • If Serum K+ is 3.3-5.2 mEq/L:
    • Start insulin and K+ repletion together.
    • Add 20-40 mEq of K+ (e.g., KCl) to each liter of IV fluid.
    • Monitor serum K+ every 2-4 hours.
  • If Serum K+ < 3.3 mEq/L:
    • ⚠️ Hold insulin.
    • Aggressively replete K+ first.
    • Begin insulin only once K+ is > 3.3 mEq/L.

⭐ Patients in DKA have a large total-body K+ deficit (3-5 mEq/kg), even with normal or high initial serum levels, due to osmotic diuresis.

High‑Yield Points - ⚡ Biggest Takeaways

  • DKA leads to a total-body potassium deficit, even with normal or high serum levels due to extracellular shifts.
  • Insulin therapy is the main driver of potassium's intracellular shift, which can cause severe hypokalemia.
  • Always check potassium before starting insulin. If K+ is < 3.3 mEq/L, replete potassium first.
  • If initial K+ is > 5.2 mEq/L, begin insulin and monitor closely.
  • For K+ between 3.3-5.2 mEq/L, give IV potassium with the insulin infusion.

Practice Questions: Electrolyte management (particularly potassium)

Test your understanding with these related questions

A 17-year-old male presents to your office complaining of polyuria, polydipsia, and unintentional weight loss of 12 pounds over the past 3 months. On physical examination, the patient is tachypneic with labored breathing. Which of the following electrolyte abnormalities would you most likely observe in this patient?

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Flashcards: Electrolyte management (particularly potassium)

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Medi-_____ is state/federal assistance for people with limited income/resources

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Medi-_____ is state/federal assistance for people with limited income/resources

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