What is the most common cause of hyperkalemia?

The most common cause of hyperkalemia is renal failure. This condition occurs when the kidneys are unable to effectively filter and excrete potassium from the bloodstream. Normally, the kidneys play a crucial role in maintaining potassium balance by regulating its excretion based on dietary intake and the body’s needs. In cases of acute or chronic renal failure, this regulatory mechanism fails, leading to an accumulation of potassium in the blood.

Additionally, while dehydration, excessive potassium supplementation, and heart failure can contribute to hyperkalemia, they are not as prevalent or as primary in causing this condition as renal failure. Dehydration can lead to decreased urine output, potentially causing hyperkalemia; however, it is not the most frequent cause. Excessive potassium supplementation is more commonly associated with individuals who have preexisting kidney issues or a particular risk of elevated potassium levels, making it less of a general cause. Heart failure can lead to fluid overload and may also affect kidney function, but the direct impact of renal failure as a primary mechanism for hyperkalemia is more significant and prevalent in clinical practice.