What causes hypokalemia

Hypokalemia is a common disease. The main cause of the disease is the relatively low potassium content in the body. We know that when the potassium content in the body is too low, it will cause great harm to the health of the body. It will lead to hypokalemia and cause continuous harm to the health of the cardiovascular system. Patients will often experience palpitations and arrhythmias, which will cause the heart to enlarge and cause dilation of peripheral blood vessels. In addition, the harm to the neuromuscular system is also relatively large. Patients often show weakness in the limbs and it will also cause more serious kidney disease. Patients may also experience difficulty breathing and may even develop coma. There are many causes of hypokalemia. It is closely related to the insufficient potassium intake or excessive potassium metabolism.

1. Reduced potassium intake:

Generally, the diet is rich in potassium, so as long as the body can eat normally, the body will not suffer from potassium deficiency. Patients with gastrointestinal obstruction, coma, and long-term fasting after surgery cannot eat. If these patients with hypokalemia are given intravenous nutrition without potassium supplementation or insufficient potassium supplementation, potassium deficiency and hypokalemia may occur. However, if insufficient intake is the only reason, the degree of potassium deficiency may not be very serious within a certain period of time due to the potassium conservation function of the kidneys. When potassium intake is insufficient, urinary potassium excretion can be reduced to below 20mmol/L within 4 to 7 days, and to 5 to 10mmol/L within 7 to 10 days. Normal urinary potassium excretion is 38 to 150mmol/L.

2. Excessive potassium excretion:

This is the most important cause of hypokalemia in children. It is common in patients with severe diarrhea, vomiting and other conditions accompanied by a large loss of digestive fluid. The concentration of K+ in feces can reach 30-50mmol/L during diarrhea. The potassium lost with feces at this time can be 10-20 times more than normal. The reason for the increase in fecal potassium content is, on the one hand, because diarrhea reduces the absorption of potassium in the small intestine, and on the other hand, the reduction in blood volume caused by diarrhea can increase the secretion of aldosterone, and aldosterone can not only increase urinary potassium excretion, but also enhance the secretion of potassium in the colon. Since the potassium content in gastric juice is only 5-10mmol/L, the loss of gastric juice is not the main cause of potassium loss during severe vomiting, and a large amount of potassium is lost through the kidneys with urine, because the metabolic alkali poisoning caused by vomiting can increase the renal excretion of potassium, and the reduction in blood volume caused by vomiting can also promote the renal excretion of potassium through secondary aldosterone increase.

3. Transfer of extracellular potassium into cells:

When extracellular potassium shifts into cells, hypokalemia may occur, but the total potassium content in the body does not decrease as a result. Hypokalemic periodic paralysis is a familial disorder in which potassium shifts from outside the cells to inside the cells. In alkali poisoning, H+ in the cell moves to the outside of the cell to compensate, while extracellular K+ enters the cell. Insulin may directly stimulate the Na+-K+-ATPase on the skeletal muscle cell membrane, thereby increasing the excretion of Na+ into the muscle cells and increasing the entry of extracellular K+ into the muscle cells.