電解質(zhì)代謝生理基礎(chǔ)

1、 Water and electrolyte disorders 1一、水、電解質(zhì)代謝的生理基礎(chǔ) (一) 體液 1. 體液及其分布 Intracellular fluidTotal (ICF) 40%(60%) interstitial fluid 15% extracellular fluid plasma 5% (ECF) 20% transcellular fluid 2% (透細胞液)2 2. 體液中主要電解質(zhì)及其分布 extracellular fluid: Na+、Cl-、HCO3- intracellular fluid： K+、HPO42- 在Na+- K+-ATPase作用下

2、，細胞內(nèi)外Na+ 、K+保持不對等分布。3 3. Osmotic pressure of body fluid (plasma) Positive ion: 151mmol/L Negative ion: 139mmol/L total 280-310mmol/L Nonelectrolyte: 10mmol/L (678.3kpa) Plasma colloidal osmotic pressure: 3.72kpa(28mmHg) 4（二）movement of water and electrolytes 1. plasma interstitial fluid capillary pr

3、otein 2. intra- and extra- cellular fluid proteins and positive ion: permeability water and negative ion: permeability (water movement balance of osmotic pressure)RBC5 3. Balance of body water and sodium drink 1200ml water intake food 1000ml (2000-2500ml) oxidation 300mlbalanceof water urine 1200-15

4、00ml water loss skin 500ml (2000-2500ml) respiration 350ml feces 150ml Balance Intake/d 100-200mmol (digestive tract) of sodium Loss/d 100-200mmol (urinary system) ECF:50% Distribution ICF: 10% of sodium 骨基質(zhì):40% (正常血清鈉:130-150mmol) 6(三) Regulation of osmotic pressure and volume Hypertonic thirst of

5、ECF 1.body water ADH ; aldosterone sodium thirst Ang ADH body volume aldosterone receptor of volume ADH 2.body water sodium ADH reabsorption of sodium 3.blood volume ANP aldosterone(ADS) tension 4.others ADH pain7Figure: regulation of ADH secretion osmotic pressure R pressure R ADH volume Rheart8二、w

6、ater and sodium disorders hypertonic hypertonic dehydration isotonic water excess isotonic hypotonic hypotonic(一) 細胞外液容量不足(extracellular fluid deficit) 1. Hypotonic dehydration sodium loss water loss serum sodium 130mmol/L plasma osmotic pressure 280mOsm/L 9 1) cause and Pathogenesis excessive loss

7、of water and sodium replaced with water only. vomiting, diarrhea; burn; diuretics; Addisons disease (ADS ) ; chronic renal failure; renal tubular acidosis 2) adaptive response and effect on body movement of body fluid ECF ICF cellular swelling Blood volume Extracellular fluid Shock dehydrated signs

8、edema of brain and lung 10 urinary alteration urine specific urine volume gravity Na+ - early ADH or stage ADS late ADH stage ADS -(注：經(jīng)腎失鈉的低滲性脫水，尿鈉不減少) 11 3) principles of treatment treating primary disease 0.9%NaCl 2. hypertonic dehydration water loss sodium loss serum sodium 150mmol/L plasma osmot

9、ic pressure310mOsm/L121) cause and pathogenesis lack of water(desert;sea) intake to drink inability(coma;baby) lung: hyperpnea(hypoxia;acidosis) skin: fever; hyperthyroidism; sweat; exposure to hot environment loss digestive tract: vomiting; diarrhea; baby diarrhea(Na+: 60mmol/L) kidney: diabetes(ke

10、tosis); diabetes insipidus diuretic(mannitol;hypertonic glucose) 13 2) effect on body hypertonic of ECF thirst movement of the body fluid ICF ECF cell dehydration Brain dehydration Sleepiness subarachnoid space bleeding Dehydration of sweat glands dehydrated fever dehydration of heat regulating cent

11、er 14 urinary alteration urine specific urine volume gravity Na+ - early ADH stage ADS late ADH stage ADS-3) principles of treatment 先水，后鹽；補水大于補鈉。 15病例1：患者，男性，40歲，吐、瀉伴發(fā)熱、口渴、尿少4天入院。 體格檢查：體溫 38.2，血壓 110/80mmHg，汗少，皮膚黏膜干燥。 實驗室檢查：血Na+ 155mmol/L，血漿滲透壓320mOsm/L，尿比重1.020。 給予 5%葡萄糖溶液 2500ml/d 和抗生素，2天后體溫、尿量正常

12、，口不渴，眼窩凹陷，皮膚彈性明顯降低，無力，腸鳴音減弱，腹壁反射消失。淺表靜脈萎陷，脈搏 110次/分，血壓 72/50mmHg，血Na+ 120mmol/L，血漿滲透壓 255mOsm/L，血K+ 3.0mmol/L，尿比重1.010，尿鈉8mmol/L。16 3. isotonic dehydration water loss sodium loss serum sodium = 130-150mmol/L plasma osmotic pressure:280- 310mOsm/L 1) cause and pathogenesis vomiting; diarrhea; gastroi

13、ntestinal suction; biliary fistula; intestinal fistula ascitic fluid; pleural effusion 172) effects on body slight thirst blood volume dehydrated signs; BP urinary alteration urine specific urine volume gravity Na+ - early ADH stage ADS late ADH stage ADS -3) principles of treatment 補偏低滲液；先補0.9%NaCl

14、18病例2： 患者，女性，38歲，因減肥連續(xù)服用瀉藥一周，現(xiàn)感虛弱乏力，偶有直立性眩暈而入院。 體格檢查：體溫36.7，血壓從入院時的110/60mmHg 很快降至 80/50mmHg，心率 100次/分，皮膚彈性差，黏膜干燥，尿量120ml/24h。 實驗室檢查：血Na+ 140mmol/L，血漿滲透壓295mOsm/L，尿比重 1.038，尿鈉 6mmol/L。19(二) 細胞外液容量過多(extracellular fluid excess) 1. water intoxication water intake , total sodium ; ECF , ICF ; hyponatre

15、mia; Serum sodium 130mmol/L 1) cause excessive water intake renal loss (acute renal failure; acute congestive heart failure) 2) effects on body brain cells swelling water moves into cells pulmonary edema 3) principles of treatment diuresis 20病例3：患者，女性，因外傷急救誤輸異型血 200ml后，出現(xiàn)黃疸和無尿。 體格檢查：體溫37，脈搏 80次/分，呼吸

16、 80次/分，血壓從入院時的110/60mmHg 很快降至 80/50mmHg。神志模糊，表情淡漠，皮膚黏膜干燥、黃染，靜脈塌陷。 實驗室檢查：血清尿素氮 15.0mmol/L，非蛋白氮 57.12mmol/L，血 K+ 6.7mmol/L。 入院后急速輸入5%10%葡萄糖溶液1500ml，生理鹽水500ml后，當晚做血液透析，透析中血壓上升并穩(wěn)定在110140/70mmHg，透析后查尿素氮為 9.46 mmol/L，非蛋白氮 44.3mmol/L，血 K+ 5.7mmol/L。 患者5天內(nèi)一直無尿，并逐漸出現(xiàn)明顯氣喘、心慌、不能平臥，嗜睡、嘔吐、頭痛、精神錯亂癥狀。查體發(fā)現(xiàn)，心率 120次/

17、分，兩肺布滿濕羅音。血 Na+ 120mmol/L，血漿滲透壓 230mOsm/L，紅細胞比容 32%。21 2. Edema interstitial fluid fluid in the body cavities hydrops fluid in the cells cellular edema (1) pathogenesis 1)imbalance of exchange between intra- and extra- body fluid (retention of water and sodium) basic mechanism: glomerular-tubular im

18、balance GFR acute glomerulonephritis heart failure reabsorption of proximal tubule sympathetic nerve filtration fraction ANP reabsorption of water and sodium 22 reabsorption of distal tubule ADH , aldosterone redistribution of renal blood flow sympathetic nerves and renin 2) imbalance of exchange between intra- and extra-vasc