【正文】 to the phase 3 of AP. C) Abnormal ECG Broad and flat T wave appears because the potassium permeability in hypokalemia is reduced, the rate of repolarization is reduced. The phase 3 is prolonged. Prolonged QRS plex are caused by reduced conductivity. Suppressive ST segment is related to the short phase 2 due to accelerated inward flow of calcium. Prominent U wave can be often seen in hypokalemia, but it is hard to explain the mechanism. 3) Effect on the acidbase balance Hypokalemia leads to metabolic alkalosis. When [K+]e of ECF reduce, the K+ of ICF moves out of the cells, at the same time, H+ moves into the cells for electric neutrality. Then the [H+] in ECF will be reduced, which is called metabolic alkalosis. ? (Depending on the primary disease) There are two kinds of ion exchange in renal tubules: K+ Na+ H+ Na+ ,. In hypokalemia, the K+Na+ exchange is reduced, the H+Na+ exchange will increase, so the excretion of H+ from kidneys is increased, which leads to acidic urine. ? Usually in alkalosis, the elimination of H+ is reduced from kidneys, and the urine should be alkaline. ? But in the alkalosis caused by hypokalemia, the urine is acidic, it is unusual, so it is called unusual aciduria. 4) Effect on the kidney ? Pathologic study found the swelling, proliferation, vacuolation in proximal tubular cells, the renal tubular cells can not produce sufficient cAMP, which is necessary for ADH to work, so the tubules lose the concentrating ability to urine. ? The volume of urine is increased and the specific gravity will reduce. ? Thirst may occur in patients with hypokalemia. 4. Principle of treatment ? 1) Etiological treatment is to correct the underlying diseases. ? 2) The major problem of replacement of potassium is to produce the hyperkalemia ? Replacement of potassium salts slowly after urination (no oliguria).見尿補鉀 ? Oral potassium chloride is better than intravenous administration. ? We must pay attention to the rate of intravenous administration and the potassium concentration of potassium chloride solution. ? ? (a) When K deficiency and oliguria, the [K+]e may not be severely reduced because of dehydration and acidosis at the same time. ? (b) It will take 1~2 days to get the balance of [K+]I and [K+]e. (10~15 days) ? Replenish KCl may correct both hypokalemia and metabolic alkalosis. ? Replenish KHCO3 may correct both hypokalemia and metabolic acidosis. . Case Discussion ? 1. A 36yearold man was hospitalized with a 3day history of fever and watery diar