From the Guidelines
Loop diuretics are the most common cause of hypokalemia among the options provided.
Causes of Hypokalemia
- Loop diuretics: These medications, such as furosemide, can lead to hypokalemia by increasing potassium excretion in the urine 1.
- Increased aldosterone secretion: Aldosterone stimulates the kidneys to retain sodium and water while excreting potassium, which can lead to hypokalemia 1.
Less Likely Causes
- Hyperparathyroidism: While hyperparathyroidism can lead to hypercalcemia, it is not a direct cause of hypokalemia.
- Metabolic acidosis: Metabolic acidosis can lead to hyperkalemia, not hypokalemia, as potassium ions move out of cells in exchange for hydrogen ions.
Key Points
- Loop diuretics have a sigmoidal dose-response curve, meaning that once the ceiling dose is reached, further increases in dose will not increase renal sodium excretion, but may increase the risk of hypokalemia 1.
- Aldosterone antagonists, such as spironolactone, can help mitigate hypokalemia caused by loop diuretics, but may also cause hyperkalemia in some cases 1.
- Monitoring of serum potassium levels is crucial when using loop diuretics or aldosterone antagonists to prevent and manage hypokalemia 1.
From the Research
Causes of Hypokalemia
The following are potential causes of hypokalemia:
- Loop diuretics: Diuretic therapy, particularly loop diuretics, is a common cause of potassium deficiency 2, 3
- Increased aldosterone secretion: Aldosterone stimulates sodium absorption and potassium secretion in the collecting tubule, leading to hypokalemia 4, 5
- Metabolic alkalosis: Alkalosis can cause hypokalemia by increasing potassium secretion in the collecting duct 4
- Hyperparathyroidism: Although hyperparathyroidism does not uniformly cause metabolic acidosis, it can lead to hypokalemia in certain cases, such as in the presence of renal tubular acidosis 5, 6
Mechanisms of Hypokalemia
The mechanisms of hypokalemia involve:
- Potassium wasting: Inappropriate potassium wasting can occur due to various factors, including diuretic therapy, abnormalities of the pituitary-adrenal axis, and renal disorders 2
- Acid-base disorders: Acid-base disorders can alter potassium transport, with acidosis causing decreased potassium secretion and alkalosis causing increased potassium secretion 4
- Hormonal influences: Hormones such as aldosterone and parathyroid hormone can influence potassium homeostasis and contribute to hypokalemia 4, 5