Serum potassium concentration is lower than 3.5mmol/L (3.5mEq/L, the range of serum potassium concentration in normal people is 3.5 ~ 5.5mmol/L), which is called hypokalemia. When hypokalemia occurs, the amount of potassium in the body does not necessarily decrease, as is the case when extracellular potassium is transferred into the cell. However, in most cases, hypokalemia is also associated with a decrease in total body potassium - potassium deficiency (potassium deficit).
1. decrease intake in potassium
The diet is rich in potassium. Therefore, as long as the normal eating, the body will not be lack of potassium. Patients who suffer from obstruction of the digestive tract, coma, and prolonged fasting after surgery can not eat. If these patients are fed intravenously without adequate potassium or potassium supplementation, they can lead to potassium deficiency and hypokalemia. However, if insufficient intake is the only cause, the extent of potassium depletion over a given period of time can be less severe because of the potassium sparing function of the kidney. When potassium intake is insufficient, the excretion of potassium in urine can be reduced to less than 20mmol/L within 4~7 days, and then decreased to 5 ~ 10mmol/L within 7~10 days (normal potassium excretion rate is 38 ~ 150mmol/L).
2. potassium is excreted too much
The potassium loss through the gastrointestinal tract: This is the most important reason for the loss of potassium in children with severe diarrhea and vomiting, common in patients with massive digestive fluid loss. When diarrhea, the concentration of K+ in feces can reach 30 ~ 50mmol/L. At this point, the amount of potassium lost with dung was 10~20 times more than normal. The fecal potassium content increased, partly because of the reduced diarrhea potassium absorption in the intestine, on the other hand is due to diarrhea caused by reduced blood volume to aldosterone secretion, and aldosterone can make uric potassium eduction increase, also can make the strengthening effect of potassium secretion of colon. The potassium content of gastric juice is only 5 ~ 10mmol/L so severe vomiting, gastric juice loss is not the main reason, the loss of potassium, and a large amount of potassium is excreted in urine by renal loss, because metabolic vomiting caused by alkali poisoning can cause renal excretion of potassium increased (Xiang Houwen), vomiting caused by reduced blood volume can also be through the secondary aldosteronism and promote the renal excretion of potassium.
(2)The renal potassium loss: This is the most important reason for the loss of potassium in adults. Common causes of increased renal potassium excretion are:
①The long-term continuous use diuretics or excessive dosage: for example, diuretics inhibit the proximal tubule sodium and water reabsorption (carbonic anhydrase inhibitor acetazolamide), diuretic drugs inhibit the mtal Cl- and Na+ reabsorption (furosemide, ethacrynic acid, thiazide , etc.) all of these can make to the original urine flow of distal renal tubular increases, where the increased flow is an important reason for promoting renal tubular secretion of potassium. The diuretic also results in increased amounts of Na+ in the distal convoluted tubule, resulting in potassium depletion by enhanced Na+-K+ exchange. Many diuretics also have a common mechanism that leads to increased potassium excretion in the kidney: increased aldosterone secretion through reduced blood volume. Furosemide, ethacrynic acid, thiazide role is to inhibit mtal reabsorption of Cl- which also inhibited the absorption of Na+. Therefore, the long-term use of these drugs can lead to hyponatremia and can lead to hyponatremia. It has been shown that any cause of hyponatremia can increase renal potassium excretion. One of the possible mechanisms is hypochloraemia seems to directly stimulate the distal renal tubular function of urinary potassium.
②Some renal diseases: such as distal renal tubular acidosis, because of the dysfunction of the distal convoluted tubule, the H+-Na+ exchange decreases and the K+-Na+ exchange increases, resulting potassium loss. In the proximal renal tubular acidosis, the reabsorption of HCO3- in the proximal convoluted tubule is decreased, and the increase of HCO3- in the distal convoluted tubule is an important cause of the increase of K excretion in the distal convoluted tubule. During the polyuria stage of acute renal tubular necrosis, the osmotic diuresis caused by the increase of urea in the renal tubule fluid, as well as the lack of water and electrolyte reabsorption in the renal tubular epithelium, may result in the increase of potassium excretion.
③Excessive adrenal cortical hormone: when the primary and secondary aldosteronism increases, the exchange of Na+-K+ in the renal distal convoluted tubule and the collecting duct is increased, thus the effect of potassium excretion and sodium retention. When Cushing syndrome occurs, the secretion of glucocorticoids and cortisol increases considerably. Cortisol also has a mineralocorticoid like effect. A large and prolonged increase in cortisol can also promote Na+-K+ exchange in the distal convoluted tubule and collecting duct, resulting in increased renal potassium excretion.
④It is not easy to reabsorption distal tubule anion increase in HCO3-, SO42-, HPO42- , NO3-, beta hydroxybutyrate, acetoacetate and penicillin is this. When they are increased in t
Hypokalemia patients mainly have the following clinical manifestations:
1. limbs limp, soft paralysis, tendon reflex dull or disappear, serious person appears breathing difficulty.
2. consciousness indifferent, eyes dull, lethargy, confusion.
3. nausea, vomiting, abdominal distension, intestinal paralysis.
4. palpitations, arrhythmias.
5. urinary system problems are common problems in patients with kidney, kidney function decreased, polyuria and low proportion, especially nocturia.
6. the lack of potassium can cause intestinal peristalsis weakened, light people have anorexia, nausea and constipation, severe hypokalemia can cause abdominal distension, paralysis of intestinal obstruction.
The examination of this disease is mainly laboratory examination of blood and electrocardiogram:
1. laboratory tests show serum potassium levels below 3.5mmol/L.
2. electrocardiogram T wave flat, bidirectional or inverted U wave and.
1. prevention primary diseases, removal of potassium deficiency caused by, such as the discontinuation of certain diuretics.
2. potassium supplementation, if hypokalemia is heavier (serum potassium is lower than 2.5 ~ 3.0mmol/L), or there are significant clinical manifestations, such as arrhythmia, muscle paralysis, etc., should be timely potassium supplementation.
The best is oral potassium supplement, 40 to 120mmol per day is appropriate. Only when the situation is critical, potassium deficiency is about to cause life-threatening complications, or because of nausea, vomiting and other reasons can the patient fail to take oral administration of potassium intravenously. In addition, potassium supplementation is only permitted when the daily urine volume is above 500ml. The concentration of potassium in the input liquid should not exceed 40mmol/L, and the amount of drip should not exceed 10mmol every per hour. When the potassium is given intravenously, the blood potassium concentration should be measured at regular intervals and monitored by electrocardiography.
Intracellular potassium recovery was slow, sometimes need to supplement potassium 4 ~ 6 days after the cells inside and outside potassium to reach equilibrium, some patients with chronic potassium deficiency requires serious potassium supplement 10 to more than 15 days.
If hypokalemia is accompanied by metabolic alkalosis or no change in acid-base status, KCL should be used. KCL also applies to hypokalemia caused by various causes, because hypokalemia itself can cause chlorine deficiency. If hypokalemia is associated with acidosis, use KHCO3 or potassium citrate to correct hypokalemia and acidosis simultaneously.
3. correct water and other electrolyte metabolism disorder caused by hypokalemia, many can also cause the loss of water and other electrolytes such as sodium, magnesium and so on, so it should be timely inspection, found it must actively. As mentioned earlier, if hypokalemia is caused by magnesium deficiency, if the magnesium is not taken up, the mere potassium supplementation is ineffective.
The prevention of this disease is the key point. There are many causes of the disease, especially in the course of clinical treatment. Should pay more attention to prevent the occurrence of this disease, first, in time to remove the cause of disease, two is possible to occur potassium deficiency, such as long time fasting, body fluid loss more patients, should be in time to add potassium.
The incidence of hypokalemia is high, and its symptoms are often concealed by primary diseases, which is easily misdiagnosed. Therefore, for the long-term lack of food, fasting, diuresis or vomiting, diarrhea patients should be timely replenishment of potassium salt. In addition, serum potassium may not be low in metabolic acidosis, and hypokalemia occurs when the acidosis is corrected.
For further identification, blood volume and blood pressure should be observed. If the blood pressure is elevated, the symptoms of aldosteronism, Cushing's syndrome, and Liddle syndrome are considered. If the blood pressure is normal, the Batter syndrome and Getelman syndrome will be considered.
In addition, hypokalemia, arrhythmia, the need for identification and other types of arrhythmias, such as ventricular tachycardia, because some patients may have no other symptoms, only for arrhythmia, so for some patients with no history of heart disease, if the arrhythmia should be suspected in the if there is disease, the etiology of this disease, should carry out laboratory tests, can generally be diagnosed.
The disease can cause some of the following complications:
1, hypokalemia associated with low calcium, low magnesium, low calcium often showed tetany, their symptoms can be confused with each other, should pay attention to in potassium calcium and magnesium added appropriate.
2, hypokalemia can cause various types of arrhythmias.
3, hyperkalemia: for hypokalemia patients due to excessive potassium treatment, possibly because of improper treatment, but cause hyperkalemia, so in order to prevent high blood potassium and potassium chloride can be added in 5% ~ 10% glucose solution.
4, hypokalemia can also cause kidney disease, so we should strictly observe the amount of urine.
1, eat more potassium food, buckwheat, corn, sweet potatoes, soybeans and other potassium elements higher.
2, eat more vegetables contain potassium, spinach, amaranth, coriander, rape, cabbage, celery, onion, garlic, lettuce, potatoes, yam, fresh peas, soybeans and other high potassium.
3, eat more seafood containing potassium. Potassium rich algae such as seaweed, hectogram 1640 mg of potassium, is 175 times the sodium potassium; ; kelp containing sodium is 22 times than sodium potassium; Sargassum containing sodium potassium is 3.1 times. Therefore, seaweed soup, seaweed steamed fish, seaweed meatballs, cold seaweed silk, seaweed stew, etc., are the top grade of potassium supplement dishes in summer.
4, eat more fruits contain high potassium , such as banana, guava, tomato, orange, peach, etc..
5, try to eat less spicy and exciting food. Such as: green onion, pepper, pepper, pepper, mustard, fennel.
6, avoid eating fried, greasy food. Such as fried dough sticks, butter, butter, chocolate and so on, these foods will help wet the role of heat, will increase the secretion of leucorrhea, is not conducive to the treatment of the disease.
7, quit smoking, alcohol, coffee and other exciting drinks.