DRG Category: 640
Mean LOS: 5.1 days
Description MEDICAL: Nutritional and Miscellaneous Metabolic Disorders with Major CC
Hypokalemia is a serum potassium ion level below 3.5 mEq/L, although symptoms do not usually occur until the potassium is below 3.0 mEq/L. Mild hypokalemia is between 3.5 and 3.0 mEq/L, moderate hypokalemia is between 2.5 and 3.0 mEq/L, and severe hypokalemia (critical value) is less than 2.8 mEq/L. As many as 20% of hospitalized patients are hypokalemic, but the condition is clinically significant in only 5% of patients.
It typically occurs when there is an increase in the potassium concentration gradient between the intracellular fluid (ICF) and extracellular fluid (ECF). Potassium functions as the major intracellular cation and balances sodium in the ECF to maintain electroneutrality in the body. It is excreted by the kidneys: approximately 40 mEq of potassium in 1 L of urine. Potassium is not stored in the body and needs to be replenished daily through dietary sources. It is also exchanged for hydrogen when changes in the body's pH call for a need for cation exchange. This situation occurs in metabolic alkalosis or other alterations that lead to increased cellular uptake of potassium, including insulin excess and renal failure. Potassium is regulated by two stimuli, aldosterone and hyperkalemia. Aldosterone is secreted in response to high renin and angiotensin II or hyperkalemia. The plasma level of potassium, when high, also increases renal potassium loss.
Because 98% of the body's potassium is intracellular, small variations in the potassium concentration gradient can cause major changes in cell membrane excitability. Hypokalemia is a relatively common electrolyte imbalance with potentially life-threatening consequences because symptoms can affect virtually all body systems. Complications of hypokalemia include paralytic ileus, cardiac dysrhythmias, shock, and sudden cardiac death.