|
Hypokalemia (American English) or hypokalaemia (British English), also hypopotassemia or hypopotassaemia (ICD-9), refers to the condition in which the concentration of potassium (K+) in the blood is low. The prefix ''hypo-'' means "under" (contrast with ''hyper-'', meaning "over"); ''kal-'' refers to ''kalium'', the Neo-Latin for potassium, and ''-emia'' means "condition of the blood." Normal plasma potassium levels are between 3.5 and 5.0 meq/l; about 98% of the body's potassium is found inside cells, with the remainder in the extracellular fluid including the blood. Alternately, the NIH denotes 3.7–5.2 meq/l as a normal range. This concentration gradient is maintained principally by the Na+/K+ pump. Hyperkalemia refers to the opposite condition in which the concentration of the electrolyte potassium (K+) in the blood is elevated. == Signs and symptoms == Mild hypokalemia is often without symptoms, although it may cause a small elevation of blood pressure, and can occasionally provoke the development of an abnormal heart rhythm. Severe hypokalemia, with serum potassium concentrations of 2.5–3 meq/l (Nl: 3.5–5.0 meq/l), may cause muscle weakness, myalgia, tremor, and muscle cramps (owing to disturbed function of skeletal muscle), and constipation (from disturbed function of smooth muscle). With more severe hypokalemia, flaccid paralysis and hyporeflexia may result. Reports exist of rhabdomyolysis occurring with profound hypokalemia with serum potassium levels less than 2 meq/l. Respiratory depression from severe impairment of skeletal muscle function is found in many patients. Some electrocardiographic (ECG) findings associated with hypokalemia include flattened or inverted T waves, a U wave, ST depression, and a wide PR interval. Due to prolonged repolarization of ventricular Purkinje fibers, a prominent U wave occurs, frequently superimposed upon the T wave and therefore produces the appearance of a prolonged QT interval. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Hypokalemia」の詳細全文を読む スポンサード リンク
|