The Importance of Potassium
Potassium is an important electrolyte that is used to transmit and conduct neurological impulses and to maintain cardiac rhythms. It is also used by the body to contract skeletal and smooth muscles. A good majority of potassium can be found in the extracellular fluid inside cells.
Muscle contractions occur when potassium moves out of cells and is replaced by sodium, which is found in larger quantities outside of cells. When the two electrolytes reverse position the muscle repolarizes. Cell membranes have a sodium-potassium pump that maintains the concentration of potassium and sodium within cells. This pump uses adenosine triphosphate (ATP) to pump potassium and sodium in and out of cells.
Potassium helps to regulate intracellular osmolality and is necessary for cell growth. When new tissues form potassium moves into the cells and leaves the cells when the tissue starts to break down. A majority of potassium is obtained through diet and is excreted in urine and feces.
A patient's serum potassium level can indicate potential health problems. Normal potassium levels are 3.5 to 5.3 millliequivalents per liter (mEq/L). A serum potassium level less than 2.5 mEq/L or greater than 7.0 mEq/L can cause cardiac arrest. Kidney disease can cause potassium levels to be imbalanced.
Hyperkalemia and hypokalemia are two conditions that are directly related to serum potassium. Hyperkalemia occurs as a result of too much serum potassium. Common signs and symptoms of hyperkalemia include nausea, cold skin, hypotension, mental confusion decreased urine output, muscle weakness and numbness or tingling in the extremities. Hypolakemia occurs when a patient has too little serum potassium. Signs and symptoms include leg cramps, muscle weakness, fatigue, polyuria, irregular pulse and bradycardia.