Potassium is a nutrient that is found in many foods. It mainly functions as an intracellular cation, keeping the cell positively charged. It also regulates contractions of the heart muscle and release of insulin, according to McMurry and Castellion in Fundamentals of General, Organic, and Biological Chemistry. High potassium levels, technically known as hyperkalemia, can indicate a variety of medical conditions.

Decreased Kidney Function

Hyperkalemia can occur when the kidneys are not working effectively, since potassium is excreted through the kidneys, according to Carol Porth in Essentials of Pathophysiology.

Excessive Intake

Porth explains that it is uncommon to consume enough potassium orally to cause hyperkalemia, but rapid intravenous administration can lead to high potassium levels.

Extracellular Influx

Potassium usually resides in the intracellular fluid compartments. However, according to Robert Lee and David Nieman in Nutritional Assessment, potassium may shift to the extracellular compartments if a person suffers extreme burns or crushing injuries.

Acidosis

Lactic acidosis and ketoacidosis can both lead to hyperkalemia through mechanisms that decrease renal excretion.

Decreased Aldosterone

Potassium is excreted through the kidneys with the help of aldosterone. According to Porth, hyperkalemia can be caused by low aldosterone production or failure of the kidneys to use aldosterone properly.

Temporary Conditions

Porth also explains that temporary hyperkalemia can occur from excessive exercise or seizures. These conditions can correct themselves naturally.

Source:

"Fundamentals of General, Organic, and Biological Chemistry;" John McMurry and Mary E. Castellion; 2003

"Essentials of Pathophysiology;" Carol Mattson Porth; 2007

"Nutritional Assessment;" Robert D. Lee and David C. Nieman; 2007