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Clinical Features

Differential Diagnosis[1]

Differential diagnosis of hypokalemia

Intracellular Shift

Decreased intake

  • Special diets or those low in potassium
  • Chronic alcohol abuse
  • Fasting
  • Eating disorders

Increased loss



  • Acute leukemia and lymphomas
  • Recovery from megaloblastic anemia
  • Hypothermia (accidental or induced)


ECG Hypokalemia.jpg


  • 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: [2].
  • 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 [3]
  • Hypokalemia in acute or recent myocardial infarction places patients at much higher risk for ventricular fibrillation[4]
    • 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


  • 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. [5]

See Also

External Links


  1. In: Tintinalli JE, Stapczynski J, Ma O, Yealy DM, Meckler GD, Cline DM. eds. Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 8e. McGraw-Hill; Accessed November 29, 2020. https://accessmedicine.mhmedical.com/content.aspx?bookid=1658&sectionid=109381281
  2. Potassium Supplement (Oral Route, Parenteral Route) from Mayo Clinic
  3. Slovis, Corey. "Electrolyte Emergencies". Presentation.
  4. Goyal A et al. Serum Potassium Levels and Mortality in Acute Myocardial Infarction. JAMA. 2012;307(2):157-164.
  5. EM:RAP 2018 August Electrolyte Emergencies - Part 1 - All Things Potassium