---------------------------------------------------------------最新资料推荐------------------------------------------------------1 水、电解质代谢紊乱（1 disorders of water andelectrolyte metabolism）1 水、电解质代谢紊乱（1 disorders of water and electrolyte metabolism） 1 水、电解质代谢紊乱（1 disorders of water and electrolyte metabolism） Dehydration (dehydration) \ hypotonic dehydration (Hypotonic dehydration) \ dehydration symptoms (Dehydrate, symptom) \ [hypertonic dehydration (Hypertonic, dehydration) / isotonic dehydration (Isotonic, dehydration) / water intoxication (Water, intoxication) \ hyponatremia (hyponatremia) \ hypernatremia (hypernatremia) A disorder of water and sodium metabolism Dehydration (dehydration): a decrease in body fluid volume (more than 2% of body weight) and a series of pathological disorders of function and metabolism. The water of the body is mainly the loss of extracellular fluid, while sodium ions are the most important cations in the extracellular fluid, so dehydration is often associated with the loss of sodium (I) hypotonic dehydration (Hypotonic, dehydration); Hypotonic dehydration: loss of sodium, more than water loss, serum sodium concentration 135mmol/L, plasma osmotic pressure 280mmol/L, and accompanied by decreased extracellular fluid volume, known as hypotonic dehydration.1 / 20Also called hyponatremia of low volume The etiology and pathogenesis of * * * * Mainly the loss of isotonic or hypotonic fluid. 1) extra renal causes A. digestive juices are lost in large amounts, B. fluids accumulate in large amounts in the body cavity, and C. accumulates large amounts of sweat or burns in large areas 2) renal causes A large number of long-term use of sodium intake or natriuretic drug limit A. (hydrochlorothiazide and furosemide and ethacrynic acid etc.)B. chronic renal interstitial disease, ascending limb of Henle and Na with renal dysfunction increased lostC. acute renal failure polyuria period, GFR increase, tubular function did not recover, sodium and water excretion increasedD. salt losing nephritis, tubular epithelial cell lesions of Ald (aldosterone) response to the decrease in sodium reabsorption in renal sodium excretion, reduce excessive The adrenal cortex and e., such as Addison disease, Ald secretion of Na, the decrease in tubular reabsorption and decrease renal sodium excretion and drainage increased F. excessive osmotic diuresis and renal excretion of Na and H2O increase 2. of the impact of the body The basic changes were obvious decrease of extracellular fluid and decrease of osmotic pressure Loss of sodium and water loss, the osmotic pressure of extracellular fluid, the decrease in---------------------------------------------------------------最新资料推荐------------------------------------------------------ extracellular to intracellular water transfer to intracellular water up to cell edema, extracellular fluid decreased more obviously Clinical manifestation 1) circulatory failure (Symptom of, circulatory, failure) The water from the cell to cell outward transfer of extracellular fluid and blood volume down down down down down down, blood pressure, shock 2) dehydration symptoms (Dehydrate, symptom) Lower skin elasticity, sunken socket, and three concave signs in infants.(3) other clinical manifestations (Other, manifestation); - thirsty: early without thirst; in late, there will be thirsty. CNS - symptoms: severe hypotonic dehydration with haziness, drowsiness, coma. - urinary sodium:: urinary sodium or no 10mmol/L. According to the clinical symptoms of the severity of clinical hypotonic dehydration of three degrees (two) hypertonic dehydration (Hypertonic, dehydration); Hypertonic dehydration: dehydration more than sodium loss, serum sodium concentration 145mmol/L, plasma osmotic pressure 310mmol/L, and accompanied by decreased extracellular fluid volume, Hypertonic dehydration. Also called low volume hypernatremia. 1. etiology and pathogenesis Dehydration or loss of low osmotic fluid is the main cause of3 / 20hypertonic dehydration 1) simple dehydration A. is C. through the lung, B. by the skin, and by the kidneys (2) loss of hypotonic fluid C. loss of hypotonic fluid through the gastrointestinal tract, B. profuse sweating, and repeated osmotic diuresis caused by repeated use of mannitol or hypertonic glucose in the a. 2., the impact on the body 1) compensatory response of organism - drink (except for thirst thirst disorder) Plasma osmotic pressure increases, osmoreceptor (+) - (+) - thirsty thirst Here, AGTII relax, thirsty central blood volume (+) - thirsty Hypertonic dehydration, saliva, throat dry down While the proportion of high - oliguria (excluding diabetes insipidus patients) In the water from the cell within the extracellular transfer to the osmotic pressure of extracellular fluid decreased somewhat These three aspects make the extracellular fluid osmotic pressure fall back, so that the early blood volume of dehydration is not easy to drop to the degree of shock 2) the clinical manifestation varies with the degree - urinary sodium Mild hypertonic dehydration (early stage) The osmotic pressure of extracellular fluid, increase blood volume decrease is not obvious, the reabsorption of water and sodium, high urine sodium. Medium and severe hypertonic dehydration---------------------------------------------------------------最新资料推荐------------------------------------------------------ (late) Blood volume and renal blood flow was significantly lower, Ald (aldosterone) secretion, increase urinary sodium down - CNS symptoms Severe hyperosmolar dehydration, intracellular fluid, brain cell dehydration and significantly decrease brain pressure decreases, the severity of the symptoms of CNS - thermal dehydration Here, the body temperature down to increase heat dissipation function, sweat gland secretory cells: liquid - shock, renal failure According to the severity of clinical symptoms, the hypertonic dehydration was three degrees (three) isotonic dehydration (Isotonic, dehydration); Isotonic dehydration: when water and sodium are lost in proportion or after losing fluid, the plasma osmotic pressure is still within normal range, the serum sodium concentration is 135~145mmol/L, and the plasma osmotic pressure is 280~ 310 mmol/L. 1. etiology and pathogenesis Vomiting and diarrhea, a large number of pleural and ascites formation, extensive burns and severe trauma, such as plasma loss. 2., the impact on the body Isotonic dehydration often has clinical manifestations of hypotonic and hypertonic dehydration. A massive loss of isotonic fluid, extracellular fluid, blood volume, blood pressure down, down to the decrease5 / 20in urine volume, body temperature, dehydration obvious appearance Isotonic dehydration can only be converted into hypotonic dehydration if only water is added to the treatment without attention to sodium supplementation. Water intoxication Water intoxication (Water intoxication): when the water intake, over regulating nerve endocrine system and kidney drainage ability, make a lot of water retention in the body, resulting in volume of intracellular fluid and extracellular fluid expansion, and the emergence of a series of diseases including hyponatremia, physical and physiological changes. 1. etiology and pathogenesis 1) take in or enter too much electrolyte free liquid 2) acute or chronic renal insufficiency 3) excessive secretion of ADH Excessive secretion of ADH is defined as abnormal secretion of ADH under certain pathological conditions. (a) ADH abnormal growth syndrome (SIADH): Hypothalamic diseases (encephalitis, brain tumors) and ectopic ADH secretion (lung, oat cell carcinoma) B) other reasons In pain, nausea and emotional stress: relax, ADH secretion of water intoxication In the case of adrenocortical function: GC (glucocorticoid), inhibition of hypothalamic ADH secretion function down down - exogenous ADH input (vasopressin and oxytocin) 4) certain special---------------------------------------------------------------最新资料推荐------------------------------------------------------ pathological states A) heart failure, hepatic ascites, effective circulating blood volume down, down to the water load increase renal drainage and water poisoning (b) hypotonic dehydration - a large amount of electrolyte free water intoxication 2., the impact on the body Prominent manifestation: increased intracellular fluid volume or cell edema When water poisoning occurs, the extracellular fluid increases obviously, and the low permeability of extracellular fluid causes a large amount of water to enter the cell Mild water intoxication, the increase of intracellular and external fluid is not obvious, the symptoms are not obvious, may be weak, dizziness and so on Acute poisoning with water intoxication can cause brain cell edema and increased intracranial pressure, which can be life-threatening test questions 1. the balance of osmotic pressure inside and outside cells mainly depends on the movement of the following substances A., Na+, B., K+, C., Cl-, D., H2O, Ca++, E. 2., a large amount of water is added to the patients with severe hypotonic dehydration, while no sodium salt is added A. hypertonic dehydration, B. isotonic dehydration, C. poisoning, D. hypokalemia, E. edema 3. what are the major characteristics of hypotonic dehydration? 4.7 / 20why is hypertonic dehydration less prone to circulatory failure in the early stage? 5., we compared the similarities and differences between hypotonic dehydration and hypertonic dehydration. Case analysis Male patients, 2 years old, diarrhea 2 days, 6-7 times a day, watery stools; vomiting 3 times, vomiting is the milk consumed, can not eat. Accompanied by thirst, oliguria and bloating. Physical examination: the spirit of malaise, T37oC, BP11.5/6.67KPa (86/50mmHg), skin elasticity, eyes sag, bregmatic subsidence, fast heartbeat and weak, no abnormal lung, abdominal distension, abdominal reflex, decreased bowel sounds, knee reflex, cold extremities. Laboratory tests: serum K+3.3mmol/L, Na+140mmol/L. What kind of water and electrolyte disorder occur in the child? On the basis of what? Comparison of three kinds of dehydration Disturbance of sodium metabolism 1. hyponatremia Hyponatremia (hyponatremia) refers to serum sodium concentrations below 135mol/l. Plasma osmolality mainly depends on the concentration of serum sodium ions, so hyponatremia is usually associated with low osmolarity. (I) hypotonic hyponatremia (hypotonic, hyponatremia): The vast majority of hyponatremia is associated with a decrease in plasma osmolality 1) low capacity hyponatremia (hypovolemic,---------------------------------------------------------------最新资料推荐------------------------------------------------------ hyponatremia) The loss of sodium is more than the loss of water, and the volume of extracellular fluid is decreased, that is, hypotonic dehydration 2) hyponatremia (isovolemic) It is seen in ADH secreting abnormal growth syndrome and osmotic reset 3) high capacity hyponatremia (hypervolemic, hyponatremia) The main causes are congestive heart failure, liver cirrhosis, ascites, nephrotic syndrome and so on, which lead to the pathological changes of the effective circulation and blood loss. Water intoxication (two) isotonic hyponatremia (chronic hyponatremia) (isotonic, hyponatremia); Hyperlipidemia or hyperlipoproteinemia patients, due to the increase of plasma lipid or protein content, serum water proportion decreased, so the serum sodium concentration under normal water, plasma sodium concentration in the clinically measured reduced, then called isotonic hyponatremia. (three) hypertonic hyponatremia (hypertonic, hyponatremia); Hyperosmolar hyponatremia: Sodium by outside impermeable solute permeability caused by increased extracellular fluid pressure increased, the water inside the cells to transfer, extracellular fluid sodium concentration decreases, which leads to the occurrence of hyponatremia in. 2. hypernatremia9 / 20Hypernatremia (hypernatremia): serum sodium concentration is higher than 145mmol/l. With the increase of plasma osmotic pressure, the basic changes of hypernatremia are common when the cells are dehydrated. (I) hyponatremia of low volume Mainly because of the large loss of water or hypotonic fluid, the loss of water exceeds the loss of sodium, which leads to the decrease of extracellular fluid and the increase of serum sodium concentration, which is called hypertonic dehydration (two) hypernatremia with equal capacity It is found in primary hypernatremia, impaired central nervous system and so on (three) hypernatremia with high volume The main reason is the excessive input of sodium solution. In patients who have been rescued from cardiac arrest and respiratory arrest, a large amount of NaHCO3 is added to fight lactic acidosis, resulting in an increase in extracellular fluid volume and sodium concentration. Two 、potassium metabolism disorder Disturbance of potassium metabolism: abnormal changes in K+ concentration in extracellular fluid (especially serum), and the patient’s clinical symptoms and signs depend mainly on the speed and extent of abnormal changes in blood potassium concentration (I) hypokalemia (hypokalemia); When serum potassium concentration is below 3.5mmol/L, it is called---------------------------------------------------------------最新资料推荐------------------------------------------------------ hypokalemia. Potassium depletion: intracellular potassium and loss of total potassium in the body. 1. causes and mechanisms 1) lack of potassium intake 2) excessive potassium loss The loss of potassium through the stomach and intestines (hypokalemia) Loss of kidney by potassium (a) loss of kidney due to increased renal flow at the distal end of the renal tubule A large number of diuretics use: increasing the distal flow velocity of the renal tubule and increasing the exchange of Na with K Renal insufficiency, renal failure (b) aldosterone: aldosterone is the major mineralocorticoid that promotes reabsorption of sodium and the secretion of potassium and hydrogen, causing potassium loss (c) renal tubule transmembrane potential increases negatively, resulting in potassium loss D) loss of potassium caused by low Mg blood Magnesium deficiency in the body, caused by the thick ascending limb of Henle epithelial cell Na, inactivation of the K-ATP enzyme, caused by potassium reabsorption and potassium loss.E) other Type I renal tubular acidosis: obstruction of the distal convoluted tubule to H+ Type II renal tubular acidosis: reabsorption of proximal convoluted tubules in HCO3- Type IV renal tubular acidosis: simultaneous presence of malabsorption11 / 20of Na+ and obstruction of the distal convoluted tubule with H+ Loss of skin by potassium 3) potassium to intracellular transfer (a) alkalosis (b) the use of insulin (c) hypokalemic familial familial periodic paralysis (d) barium poisoning, crude cottonseed oil poisoning 2. effects of hypokalemia on the body Related to the speed, amplitude and duration of blood potassium lowering, the faster the rate of blood potassium lowering, the lower the serum potassium concentration, the greater the impact on the body. 1) the effect on neuromuscular excitability The excitability and conductivity of nerve and muscle tissue are significantly affected Acute hypokalemia, extracellular fluid with constant liquid concentration decreased, intracellular potassium concentration, the results make the intracellular potassium concentration, the ratio of increase of intracellular potassium efflux increased, the absolute value of the resting membrane potential increases, and increase the threshold potential gap, the stimulation threshold excited should also be increased, it caused the excitability of nerve muscle cells decreased. When chronic hypokalemia occurs, the extracellular potassium can be replenished by intracellular potassium, because the potassium concentration in the---------------------------------------------------------------最新资料推荐------------------------------------------------------ extracellular fluid is slowed down, so the symptoms are not obvious. Clinical manifestations: symmetrical limbs, flaccid paralysis, even soft paralysis, paralytic ileus, abdominal distension and so on. Physical examination: reduction of muscle tone in the limbs and decrease or disappearance of tendon reflex. Reason: the excitability of skeletal muscle cells decreases, and the gastrointestinal smooth muscle can also be involved 2) the effect on the heart Mainly cause arrhythmia, severe ventricular fibrillation, leading to heart failure A) physiological changes of myocardium [K +]e decreased, membrane permeability decreased, phase 4 K + efflux decreased, Na + or Ca2 + increased, and autonomic cells automatically increased rapidly and increased automaticity; The reduced membrane permeability decreased [K]e?? Em cell move, Em-Et spacing increased excitability?; The Em shift and Em-Et spacing decrease, the slope of the 0 phase curve increases, the front potential decreases, and the conductivity decreases; The [K +]e decreased 2? Ca2 + influx of [Ca2 +]i increased rapidly accelerated?? myocardial contractility increased (severe and chronic hypokalemia due to intracellular potassium deficiency, affecting cell metabolism, myocardial damage,13 / 20decrease of myocardial contractility). (b) electrocardiographic changes The obvious U wave after S-T segment depression and T wave is characteristic of hypokalemia Conduction prolongation, P-R interval prolongation, ORS wave presentation and broadening The calcium influx in the 2 stage accelerates the potassium efflux, the 2 stage repolarization accelerates and the S-T depression decreases The 3 phase of potassium efflux slowed down to repolarization, and the 3 phase extended to U wave obviously C) arrhythmia In hypokalemia, the myocardial excitability increased, the supernormal period prolonged and the ectopic pacemaker increased automaticity. At the same time, the conductivity decreased, the conduction slow and the effective refractory period shortened, and it was easy to cause excited reentry. Therefore, hypokalemia is prone to premature beats, atrioventricular block, ventricular fibrillation, and other arrhythmias. 3) the influence on acid-base equilibrium Hypokalemia may cause alkalosis (paradoxical uric acid) 4) the effect on the kidney The accumulation of renal dysfunction occurs in the so-called depletion of postassiun (nephropathy) 5) the effect on blood vessels Reducing peripheral vascular resistance to hypokalemia is associated with vertigo, hypotension and other---------------------------------------------------------------最新资料推荐------------------------------------------------------ symptoms 3. prevention and treatment principle of hypokalemia 1) prevention and treatment of primary diseases 2) proper potassium supplementation during treatment. The principle of potassium supplementation: feeding can be taken orally as possible potassium supplement; intravenous potassium supplementation should pay attention to low concentration (20~40 mmol/L) and low flow rate (10 mmol/h); daily potassium supplementation can be controlled at 40~120 mmol. Special attention should be paid to intravenous potassium supplementation only when the renal function is good. When the amount of urine is greater than 500 ml, the potassium supplementation is safe. Potassium deficiency is caused by magnesium deficiency, Magnesium should be supplied before potassium can be effectively supplied. Attention should be paid to the acid-base balance of the patient. (two) hyperkalemia (hyperkalemia); Serum K + concentration greater than 5.5 mmol/L is called hyperkalemia. 1. causes and mechanisms 1) excessive penetration 2) renal excretion of potassium decreased Acute renal failure, oliguria stage, end-stage renal failure. High potassium type distal tubular acidosis Decreased aldosterone secretion or decreased renal15 / 20tubular aldosterone response to aldosterone Long term use of diuretics that can cause potassium retention 3) extracellular release of stromal cells Acidosis A great deal of hemolysis or tissue damage and necrosis When diabetic ketoacidosis occurs Membrane dysfunction of sodium pump Familial familial periodic paralysis of hyperkalemia 2. effects of hyperkalemia on the body 1) the effect on neuromuscular excitability Mild hyperkalemia (5.5 ~ 7.0mmol/L) often results in increased excitability. There are hand foot and foot abnormalities, tremors, myalgia, or colic, and diarrhea; Severe hyperkalemia (7 ~ 9.0mmol/L) often makes the muscle cells appear to be depolarized and blocked, causing muscle paralysis, and clinical weakness of muscle, flaccid paralysis and other symptoms. 2) the effect on the heart The effect on the heart, like hypokalemia, can also cause arrhythmias or ventricular fibrillation, but unlike hyperkalemia, severe hyperkalemia can cause cardiac arrest. (a) characteristics of myocardial physiological changes [K +]e increased, and the permeability of the membrane to K + increased after the repolarization of the self regulatory cells. The 4 phase of K + flow increased, the automatic depolarization slowed down, and the automaticity decreased. Increase of [K +]e, decrease of---------------------------------------------------------------最新资料推荐------------------------------------------------------ Em negative value in cardiac working cells, decrease of Em-Et distance, increase of excitability in mild disease and decrease in severe condition. The Em-Et interval is reduced. In the 0 stage, the depolarization is decreased and the potential is decreased, and the conductivity is decreased. Increase of [K +]e, decrease of calcium influx in 2 stage and decrease in contractility. B) changes in the electrocardiogram The action potential of cardiac myocytes decreased and P wave decreased, widened or disappeared The conductivity decreased, prolonged P-R interval, QRS composite is wide The T wave is high, the Q-T interval shortens and the S-T elevation (c) the manifestation of arrhythmia Acute hyperkalemia is reduced and slow conduction conductivity caused by unidirectional conduction block, and effective refractory period shortened, and also easy to cause the reentry arrhythmia, including ventricular fibrillation. Severe hyperkalemia can result in cardiac arrest due to reduced automaticity, block of conduction, and loss of excitability 3) the influence on acid-base equilibrium Hyperkalemia results in the metastasis of H + to the extracellular region and the decrease of H + in kidney, so metabolic acidosis can occur. (paradoxical alkaline urine) 3.17 / 20prevention and treatment principle of hyperkalemia 1) prevention and treatment of primary diseases 2) reduce blood potassium: myocardial toxicity against high potassium; promote K+ into cells; accelerate K+ excretion Hypokalemia * reasons Insufficient intake of potassium: can not eat or fasting, stomach, parenteral K solution too much: often iatrogenic, such as kidney dysfunction, more rapid, potassium supplementation Potassium loss or discharge excessive vomiting, diarrhea, intestinal fistula; using Paul sodium and osmotic diuresis; renal dysfunction and interstitial renal disease; aldosterone; magnesium deficiency; sweat reduction; renal failure and some kidney diseases; Adrenal cortical insufficiency; potassium sparing diuretic use * k the abnormal distribution of extracellular potassium into the cell: alkalosis; insulin; periodic paralysis; intracellular potassium escape cell barium poisoning: acid poisoning; severe hypoxia; periodic paralysis; hemolysis or serious tissue damage excessive muscle movement; the use of digitalis or propranolol. Effects on the organism * nerve muscle excitability is chronic; varies little Acute: lower chronic: little change Acute: mild increase, severe decrease * cardiac automaticity increases and decreases Excitability increased, slightly increased, decreased when---------------------------------------------------------------最新资料推荐------------------------------------------------------ severe Decreased conductivity Decreased contractility Extend the ECG characteristics of the P-R interval, QRS wave width; S-T segment depression, T wave flat, U wave, Q-T wave, P wave interval prolonged low width, prolonged P-R interval, QRS wave width; S-T elevation, T wave tip The Q-T interval is shortened or normal * clinical presentation, tachycardia, arrhythmia, or ventricular fibrillation, arrhythmia, or cardiac arrest * acid base balance secondary metabolic alkalosis secondary metabolic acidosis * gastrointestinal peristalsis, abdominal distension, paralytic ileus, colic, diarrhea Three, acid-base balance and acid-base balance disorders Under physiological conditions, the pH of the extracellular fluid is between pH37.35-7.45 and the average value is 7.40. Extracellular fluid pH is in this relatively stable state, that is called acid-based (balance), that is, the relative concentration of hydrogen ion concentration ([H+]) in the blood. The maintenance of acid-base balance depends on the humoral buffer system and the mediation of the lungs and kidneys. The acid-base equilibrium disorder refers to various causes accumulation or lack of body acidic or alkaline substances, leading to environmental damage in body fluid acid-base19 / 20homeostasis, which is caused by various reasons of arterial blood [H+] exceeded the normal range (increase or decrease) of the pathological changes.。
