Learning objectives
- Definition, diagnosis, and management of hypokalemia
Definition
- 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
Causes
| Gastrointestinal loss | Chronic 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 |
| Hypomagnesemia | |
| Medications | Diuretics (thiazides, loop-, and osmotic diuretics) Laxatives Beta-2-agonists (albuterol, terbutaline) Amphotericin B Antibiotics (carbenicillin and penicillin in high doses) Theophylline |
Management
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.
Clinical updates
Coppola et al. (British Journal of Anaesthesia, 2025) review diuretic use in critically ill patients and highlight that loop and thiazide diuretics commonly cause hypokalemia due to increased distal sodium delivery and potassium loss. They emphasize that combination diuretic therapy, high-dose strategies, and continuous infusions increase the risk of electrolyte disturbances, requiring close potassium monitoring and tailored supplementation. The authors also note that potassium-sparing agents (e.g., spironolactone, amiloride) may help prevent or treat diuretic-induced hypokalemia, particularly in resistant or prolonged ICU diuresis.
- Read more about this topic HERE.
