Waterandelectrolytedisorders

一、水、電解質(zhì)代謝的生理基礎(chǔ)

(一)體液1.體液及其分布

IntracellularfluidTotal(ICF)40%(60%)interstitialfluid15%extracellularfluidplasma5%(ECF)20%transcellularfluid2%(透細(xì)胞液)

2.體液中主要電解質(zhì)及其分布

extracellularfluid:Na+、Cl-、HCO3-

intracellularfluid：K+、HPO42-

在Na+-K+-ATPase作用下，細(xì)胞內(nèi)外Na+、K+保持不對(duì)等分布。（二）

movementofwaterandelectrolytes

1.plasmainterstitialfluid

capillaryprotein

2.intra-andextra-cellularfluidproteinsandpositiveion:permeabilitywaterandnegativeion:permeability(watermovementbalanceofosmoticpressure)RBC

3.Balanceofbodywaterandsodium

drink

1200mlwaterintakefood1000ml(2000-2500ml)oxidation300ml

balanceofwaterurine1200-1500mlwaterlossskin500ml

(2000-2500ml)

respiration

350mlfeces150ml

BalanceIntake/d100-200mmol(digestivetract)ofsodiumLoss/d100-200mmol(urinarysystem)ECF:50%DistributionICF:10%

ofsodium骨基質(zhì):40%(正常血清鈉:130-150mmol)(三)

RegulationofosmoticpressureandvolumeHypertonicthirstofECF1.bodywaterADH;aldosteronesodiumthirstAngⅡADH

bodyvolume

aldosterone

receptorofvolumeADH

2.bodywatersodiumADH

reabsorptionofsodium3.bloodvolumeANPaldosterone(ADS)tension4.othersADHpain二、waterandsodiumdisorders

hypertonichypertonicdehydrationisotonicwaterexcessisotonichypotonichypotonic(一)細(xì)胞外液容量不足(extracellularfluiddeficit)

1.Hypotonicdehydrationsodiumloss＞waterlossserumsodium＜130mmol/L

plasmaosmoticpressure＜280mOsm/L

1)causeandPathogenesisexcessivelossofwaterandsodiumreplacedwithwateronly.vomiting,diarrhea;burn;diuretics;Addison’sdisease(ADS);chronicrenalfailure;renaltubularacidosis2)adaptiveresponseandeffectonbody①

movementofbodyfluidECFICFcellularswellingBloodvolumeExtracellularfluid

Shockdehydratedsignsedemaofbrainandlung

②

urinaryalterationurinespecificurinevolumegravity[Na+]----------------------------------------------------------earlyADH±

orstageADS

lateADHstageADS-----------------------------------------------------------(注：經(jīng)腎失鈉的低滲性脫水，尿鈉不減少)

1)causeandpathogenesislackofwater(desert;sea)①

intaketodrinkinability(coma;baby)lung:hyperpnea(hypoxia;acidosis)

skin:fever;hyperthyroidism;sweat;exposuretohotenvironment

②

lossdigestivetract:vomiting;diarrhea;babydiarrhea([Na+]:60mmol/L)kidney:diabetes(ketosis);diabetesinsipidus

diuretic(mannitol;hypertonicglucose)

2)effectonbody①

hypertonicofECFthirst②

movementofthebodyfluidICFECFcelldehydration

Braindehydration

SleepinesssubarachnoidspacebleedingDehydrationofsweatglandsdehydratedfeverdehydrationofheatregulatingcenter

③urinaryalterationurinespecificurinevolumegravity[Na+]----------------------------------------------------------------earlyADHstageADS±

lateADHstageADS

-----------------------------------------------------------------3)principlesoftreatment先水，后鹽；補(bǔ)水大于補(bǔ)鈉。

3.isotonicdehydration

①waterloss≈sodiumloss

②serumsodium=130-150mmol/L

③plasmaosmoticpressure:280-310mOsm/L

1)causeandpathogenesis

①

vomiting;diarrhea;gastrointestinalsuction;biliaryfistula;intestinalfistula

②

asciticfluid;pleuraleffusion

2)effectsonbody①slightthirst②bloodvolumedehydratedsigns;BP

③urinaryalterationurinespecificurinevolumegravity[Na+]------------------------------------------------------------------earlyADHstageADS

lateADHstageADS------------------------------------------------------------------

3)principlesoftreatment補(bǔ)偏低滲液；先補(bǔ)0.9%NaCl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(shí)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(shí)驗(yàn)室檢查：血Na+140mmol/L，血漿滲透壓295mOsm/L，尿比重1.038，尿鈉6mmol/L。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(wú)尿。體格檢查：體溫37℃，脈搏80次/分，呼吸80次/分，血壓從入院時(shí)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(shí)驗(yàn)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(dāng)晚做血液透析，透析中血壓上升并穩(wěn)定在110～140/70mmHg，透析后查尿素氮為9.46mmol/L，非蛋白氮44.3mmol/L，血K+5.7mmol/L。患者5天內(nèi)一直無(wú)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(cuò)亂癥狀。查體發(fā)現(xiàn)，心率120次/分，兩肺布滿(mǎn)濕羅音。血Na+120mmol/L，血漿滲透壓