Hypokalemia

Background

Clinical Features

Differential Diagnosis
Differential diagnosis of hypokalemia

Intracellular Shift

Decreased intake

Increased loss

Drugs

Evaluation


Management
  • Potassium repletion (PO or IV)
    • Every 10mEq KCl → serum K ↑ ~0.1mEq/L
    • PO preferred (if symptomatic or level is <2.5, both oral and IV should be given)
  • Oral potassium
    • Inexpensive and rapidly absorbed
    • KCl tablet (elixir form available but has poor taste)
    • K-Dur (extended release tablet) is large and may be difficult to swallow
    • If sending patient home can also increase food intake of potassium as an alternative or supplementing potassium tablets. Printable table that can be given to the patient available at this reference: [1].
  • Intravenous potassium
    • Must be given in dilute solutions at slow rate (10meq/hour) to minimize side effects and cardiac toxicity
    • Generally should not give more than 40mEq via IV
    • Side effects: Local tissue burning, phlebitis, sclerosis
  • Also treat Hypomagnesemia if present
  • Re-check ECG after treatment [2]
  • Hypokalemia in acute or recent myocardial infarction places patients at much higher risk for ventricular fibrillation[3]
    • Previous studies and many professional organizations recommend maintaining K between 4.0 - 5.0 mEq/L in MI patients
    • However, more recent studies suggest 3.5 - 4.5 mEq/L results in the lowest mortality

Disposition
  • Based on underlying cause
  • One admission criteria is potassium less than 3.0 meq/L and a QTc that is close to or more than 500 msec. [4]

See Also

References
  1. Potassium Supplement (Oral Route, Parenteral Route) from Mayo Clinic
  2. Slovis, Corey. "Electrolyte Emergencies". Presentation.
  3. Goyal A et al. Serum Potassium Levels and Mortality in Acute Myocardial Infarction. JAMA. 2012;307(2):157-164.
  4. EM:RAP 2018 August Electrolyte Emergencies - Part 1 - All Things Potassium
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