Question 2: The cause of hypokalemia is 1. The decrease of potassium intake is generally due to the rich potassium in the diet. Therefore, as long as you can eat normally, your body will not be short of potassium. Patients with postoperative digestive tract obstruction, coma and long-term fasting, if they are not supplemented with potassium at the same time or insufficient potassium, can lead to potassium deficiency and hypokalemia. However, if insufficient intake is the only reason, the degree of potassium deficiency in a certain period of time can not be very serious because of the potassium preservation function of the kidney. 2. Excessive potassium excretion (65,438+0) leads to the loss of potassium through the gastrointestinal tract, which is the most important cause of potassium loss in children, and is common in patients with severe diarrhea, vomiting and massive loss of digestive juice. When vomiting violently, the loss of gastric juice is not the main cause of potassium loss, but a large amount of potassium is lost through the kidney and urine, because metabolic alkalosis caused by vomiting can increase potassium excretion in the kidney, and the reduction of blood volume caused by vomiting can also promote potassium excretion in the kidney through secondary aldosterone increase. (2) Renal potassium loss This is the main cause of potassium loss in adults. The common factors causing the increase of renal potassium excretion are: ① long-term continuous use or excessive use of diuretics; ② Some kidney diseases; ③ Excessive adrenocortical hormone; ④ The number of anions in distal convoluted tubules that are not easily reabsorbed increases; ⑤ magnesium deficiency; ⑥ Alkaline poisoning. (3) The potassium content of potassium-deficient sweat through the skin is only 9mmol/L ... Generally speaking, sweating will not lead to hypokalemia. However, excessive sweating will also lead to the loss of potassium when heavy physical labor is carried out in high temperature environment. 3. Extracellular potassium is transferred into cells. When extracellular potassium is transferred into cells, hypokalemia can occur, but the total amount of potassium in the body does not decrease. (1) Extracellular potassium is transferred to cells during hypokalemic periodic paralysis, which is a familial disease. (2) H+ in alkalosis cells moves to the outside of the cell to compensate, while K+ outside the cell enters the cell. (3) Excessive insulin and hypokalemia occurred when high-dose insulin was used to treat diabetic ketoacidosis. (4) Barium poisoning is caused by some acid-soluble barium salts such as barium acetate, barium carbonate, barium chloride, barium hydroxide, barium nitrate and barium sulfide. 4. Raw cotton oil poisoning In recent twenty or thirty years, a kind of hypokalemic paralysis has appeared in some cotton producing areas in China, which is also called "soft disease" in some provinces.
Question 3: What is the basic reason and mechanism of potassium metabolism disorder?
1. Insufficient potassium intake is found in patients who can't eat for a long time (such as digestive tract obstruction, coma and long-term fasting after operation).
2. Too much potassium loss
(1) Potassium loss through gastrointestinal tract and digestive juice loss are the most common causes of hypokalemia. Mainly seen in frequent vomiting, diarrhea, massive gastrointestinal sputum aspiration and intestinal fistula; Abuse of enema or laxative. The mechanism is as follows: ① the potassium content of digestive juice is higher than that of plasma, so the loss of digestive juice will inevitably lose a lot of potassium; ② When a large amount of digestive juice is lost and blood volume is reduced, aldosterone secretion can be increased, and aldosterone can promote renal potassium excretion.
(2) There are many reasons for the loss of renal potassium, which can be seen in the following situations: ① Using some diuretics, such as medullary loop or thiazide diuretics: the main mechanism is to inhibit the reabsorption of chlorine and sodium by the thick segment of ascending branch of medullary loop and the beginning of distal convoluted tubule, so that the amount of sodium reaching distal convoluted tubule increases, and the exchange volume of K+ and Na+ increases, which leads to the increase of potassium excretion; In addition, endogenous and exogenous osmotic diuresis, such as hypertonic mannitol, can also make the body lose potassium; Diuretics that inhibit carbonic anhydrase activity in proximal convoluted tubules can also promote potassium excretion by increasing the exchange of K+ and Na+ in distal convoluted tubules. ② Hypersecretion of aldosterone: When primary aldosteronism, secondary aldosteronism, Cushing's syndrome and ectopic ACTH secretion increase, renal potassium excretion increases; ③ The original urine flow rate of distal convoluted tubule increases: various renal diseases, especially renal interstitial diseases, such as
, renal pelvis, nephritis, due to sodium water reabsorption disorder, the flow velocity of distal convoluted tubule fluid increases, resulting in excessive potassium excretion; ④ Magnesium deficiency: The potassium reabsorption of ascending branch of medullary loop depends on Na+-K+-ATPase of renal tubular epithelial cells, which requires the activation of Mg2+. When magnesium is deficient, the enzyme may be inactivated due to insufficient Mg2+ in the cell, and the potassium reabsorption is blocked, resulting in potassium loss. ⑤ During distal renal tubular acidosis, renal tubular H+ excretion decreases, so the exchange capacity of K+ and Na+ increases, resulting in increased urinary potassium excretion; ⑥ When the number of anions which are difficult to be reabsorbed in the distal convoluted tubule such as SO42-, HPO4-, HC03-, NO2-, β-hydroxybutyric acid, acetoacetic acid, penicillin and carbenicillin in the distal convoluted tubule fluid increases, the negative charge of the tubular fluid increases, so the positively charged K+ is easily transferred from the renal tubular epithelial cells to the lumen, thus increasing the excretion of potassium.
(3) Excessive sweating due to potassium loss through the skin can also cause hypokalemia.
3. Too much potassium enters the cell, which leads to hypokalemia due to the transfer of potassium from extracellular to intracellular, but the total amount of potassium in the body has not changed, mainly in the following situations: ① hypokalemic periodic paralysis. Especially in the attack period, potassium suddenly moves into human cells, leading to a sharp drop in serum potassium concentration and muscle relaxation or paralysis. If left untreated, muscle tension will recover after 6 ~ 48 hours, potassium will return to the extracellular space, and plasma potassium concentration will return to normal. ② Glycogen synthesis was enhanced. For example, when high-dose insulin is used to treat diabetic ketoacidosis, blood potassium enters cells with glucose in large quantities to synthesize glycogen, so blood potassium decreases; ③ Acute alkalosis. The rapid transfer of extracellular potassium to cells can cause hypokalemia. When the pH value increases by 0. 1, the blood potassium concentration will decrease by 10% ~ 15%. ④ The activity of B adrenoceptor is enhanced, which can be activated by cAMP to activate Na+-K+ pump and promote potassium to enter cells; ⑤ Barium poisoning. Barium acetate, barium carbonate, barium chloride, barium hydroxide, barium nitrate and barium sulfate can specifically block the outflow of potassium from cells, resulting in extracellular low potassium.
Question 4: What is the cause of potassium deficiency in human body and why? The symptom of potassium deficiency is that potassium is the main cation in intracellular fluid, which is closely related to the normal physiological function of myocardium. There should be enough potassium supply in the diet to meet the needs of the body. Old people have low potassium content, so they should pay attention to dietary supplement. Potassium-rich foods mainly include fruits and vegetables whose serum potassium concentration is lower than 3.5 mmol/L, which is called hypokalemia. Hypokalemia is more common in long-term fasting or eating less, and potassium salt intake is insufficient; Excessive potassium excretion caused by vomiting, diarrhea and long-term use of diuretics such as furosemide. The main clinical manifestations are nerve and muscle dysfunction. The more potassium is lost, the faster it is, or the more Na+ and Ca+ concentrations increase at the same time, the more obvious the symptoms are. Hypokalemia is often mixed with primary symptoms, which easily delays the diagnosis and should be paid attention to. When potassium is supplemented intravenously, the urine volume must be above 30ml// hour. Don't overdo it. Intravenous injection is strictly prohibited. What are the symptoms of hypokalemia? 1. Limbs are weak and flaccid, tendon reflex is slow or disappears, and in severe cases, it is difficult to breathe. 2. Indifferent mind, dull eyes, lethargy and unconsciousness. 3. Nausea, vomiting, abdominal distension and intestinal paralysis. 4. Palpitation and arrhythmia. What tests do hypokalemia need to do? 1. Serum potassium is lower than 3.5 mmol/L .. Electrocardiogram showed that T wave was flat, bidirectional or inverted, and U wave appeared. What do you think of 1? Actively treat the primary disease that causes K+ deficiency and restore normal diet. 2. Potassium supplementation: (1) When supplementing potassium, try to take it orally if possible; If you can't take it orally, add it intravenously. (2) intravenous injection of potassium chloride, it is forbidden to push injection, generally add glucose solution drip, the concentration shall not exceed 3%, the drop rate shall not exceed 80 drops per minute; Do not drop more than 6g-8g every 24 hours. (3) When accompanied by acidosis, potassium bicarbonate can be used instead. (4) potassium glutamate can be used for patients with liver function damage. (5) When the heart is obviously involved or accompanied by magnesium deficiency, potassium magnesium L- aspartate can be used. I hope it helps you!