Hypokalemia - NYSORA

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Learning objectives

  • Definition, diagnosis, and management of hypokalemia


  • Hypokalemia is a reduced level of potassium (K+) in the blood
  • Serum potassium < 3.5 mmol/L
  • Mild low potassium does not typically cause symptoms
  • Life-threatening symptoms usually occur at concentrations < 2.5 mmol/L

Signs and symptoms

  • Gastro-intestinal:
    • Nausea
    • Constipation
    • Gastrointestinal paralysis
  • Neuromuscular: 
    • Paresthesias
    • Muscle cramps
    • Ascending paralysis of the extremities (quadriplegia)
  • Respiratory failure
  • Cardiac:
    • Heart failure
    • Progressive ECG changes
      • Depressed ST segment
      • Diphasic T wave
      • Prominent U wave


Gastrointestinal lossChronic diarrhea
An intracellular shift of K+Due to insulin administration or excessive insulin secretion
Renal loss
Cushing’s syndrome
Primary Hyperaldosteronism
Rare syndromes Bartter syndrome
Gitelman syndrome
Liddle syndrome
Diuretics (thiazides, loop-, and osmotic diuretics)
Beta-2-agonists (albuterol, terbutaline)
Amphotericin B
Antibiotics (carbenicillin and penicillin in high doses)


Hypokalemia, K+, ECG, glucose

Suggested reading

  • Kardalas E, Paschou SA, Anagnostis P, Muscogiuri G, Siasos G, Vryonidou A. Hypokalemia: a clinical update. Endocr Connect. 2018;7(4):R135-R146.
  • Viera AJ, Wouk N. Potassium Disorders: Hypokalemia and Hyperkalemia. Am Fam Physician. 2015;92(6):487-495.

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