DisordersofPotassiumMetabolism鉀代謝障礙酸堿平衡紊亂第1頁(yè)Outline

NormalpotassiummetabolismandregulationHypokalemiaHyperlalemiaCasediscussion鉀代謝障礙酸堿平衡紊亂第2頁(yè)1.thetotalpotassium

ofbody:

intracellular:98％（140-160mmol/L）

extracellular：2％（3.5-4.5mmol/L）Normalpotassiummetabolism鉀代謝障礙酸堿平衡紊亂第3頁(yè)2.potassiumpresentsinthefood,suchasmilk,peanutpotatoes,saltsubstitute.Potassiumexcretepathway:kidneythroughurine:90％

Stool(feces):10％Sweatnormalserumpotassium:3.5-5.5mmol/Lbalancebetweenintra-andextracellularK+

normal:15h鉀代謝障礙酸堿平衡紊亂第4頁(yè)3.regulationofpotassiumhomeostasis

TranscellulartransferRenalregulation鉀代謝障礙酸堿平衡紊亂第5頁(yè)(1)PotassiumtranscellulartransferPump-leakmechanismfactors:PotassiumconcentrationinECFAcid-basebalanceInsulinCatecholamineOsmolarityExerciseTotalbodypotassium鉀代謝障礙酸堿平衡紊亂第6頁(yè)(2).RenalregulationforpotassiumexcretionGlomerularfiltrationReabsorptionbytheproximaltubuleandtheloopofHenleRegulationofpotassiumexcretioninthedistalandcollectingtubules鉀代謝障礙酸堿平衡紊亂第7頁(yè)Sodium-potassiumATPasePermeabilityofluminalmembraneforpotassiumReabsorptionincollectingtubulesHydrogen-potassiumATPase-protonpumpMechanismofpotassiumexcretionindistalandcollectingtubules:鉀代謝障礙酸堿平衡紊亂第8頁(yè)Influencingfactorsofpotassiumexcretionindistalandcollectingtubules:PotassiumconcentrationinECFAldosteroneDistalflowrateAcid-basebalance(3)PotassiumexcretionincolonThesameastheexcretioninkidney鉀代謝障礙酸堿平衡紊亂第9頁(yè)4.physiologicalfunctionofpotassiummaintaincellularmetabolismmaintaincellularrestingmembranepotentialregulatetheosmolarityandacid-basebalance鉀代謝障礙酸堿平衡紊亂第10頁(yè)DisorderofpotassiummetabolismNormalserumpotassium:3.5-5.5mmol/LHypokalemiaHyperkalemia鉀代謝障礙酸堿平衡紊亂第11頁(yè)5.influencingfacterofpotassiumhomeostasisacidosisalkalosishypoxiaseruminsulinserum

damageofcells[K+]ADS[K+]catabolismanabolism

distalflowratedistalflowrate鉀代謝障礙酸堿平衡紊亂第12頁(yè)1.Definition:Hypokalemiaisdefinedasadecreaseinserumpotassiumlevellessthan3.5mmol/L.Ⅱ.hypokalemia鉀代謝障礙酸堿平衡紊亂第13頁(yè)2.causes(1).intake↓(2).discharge↑①digestivetract②kidneys：③skin鉀代謝障礙酸堿平衡紊亂第14頁(yè)GI:vomiting;diarrhea;GastrointestinalsuctionSkin:excessivesweatsfurosemidediureticlossesdiamoxdiureticphaseofARFrenal:

primaryhyperaldosteronismlackofmagnesiumrenaltubularacidosis

osmoticdiuresis

鉀代謝障礙酸堿平衡紊亂第15頁(yè)(3).AbnormalitydistributionofpotassiummoveintocellsacutealkalosisinsulinoverdoseBariumpoisoningBeta-receptorexcitomotoryhypokalemicperiodicparalysis鉀代謝障礙酸堿平衡紊亂第16頁(yè)3.alterationsofmetabolismandfunctionNervecellsskeletalmusclesgastrointestinalsmoothmuscleMyocardialcells鉀代謝障礙酸堿平衡紊亂第17頁(yè)

Effectsonbody

(1).nervesandmusclesacutehypokalemiaexcitability

0mv

serum[K+]-30mvAP-60mvTP(Et)-90mvRP(Em)

hyperpolarization鉀代謝障礙酸堿平衡紊亂第18頁(yè)(2).Heartarrhythmia

0mv

serum[K+]-30mv-60mv-90mv

depolarization

鉀代謝障礙酸堿平衡紊亂第19頁(yè)Excitability:[K+]ECF

K+permeabilitydepolarizationrepolarizationexcitabilityECGTwaveConductivity:RP0phaseofAP

conductivityconductiveblockunidirectionalblockECGP-R

鉀代謝障礙酸堿平衡紊亂第20頁(yè)Autorhythmicity:Contractility:acute;chroniceffectsonheartcardiacexcitability↑c(diǎn)ardiacconductivity↓cardiacautomaticity↑c(diǎn)ardiaccontractibility↑→↓鉀代謝障礙酸堿平衡紊亂第21頁(yè)(3).Renalpolyuria(sensitivityofADH)(4).GIsmoothmusclesHyperpolarization(5).acid-basebalancemetabolicalkalosisparadoxicalaciduria鉀代謝障礙酸堿平衡紊亂第22頁(yè)4.principlesofpreventionandtreatment1.treatmentofprimarydisease2.principlesofpotassiumcompensationoralapplicationisbetterGivepotassiumaccordingtotheurineconcentration40mmol/L，slowly10-20mmol/htoobserve：heartratecardiacrhythmconsciousnessacidbase鉀代謝障礙酸堿平衡紊亂第23頁(yè)1.definition:hyperkalemiaisdefinedasserumpotassiumexceeding5.5mmol/L.Ⅲ.hyperkalemia鉀代謝障礙酸堿平衡紊亂第24頁(yè)2.causes(1).increasedintakeofpotassium(2).Impairedrenalpotassiumexcretion：①renaldysfunction②ALD↓③potassium-sparingdiuretics鉀代謝障礙酸堿平衡紊亂第25頁(yè)(3).abnormalpotassiumtranscellularditribution①acuteacidosis②hypoxia→ATP↓③tissuedamage④hyperkalemicperiodicparalysis⑤Diabetes⑥Beta-receptorinhibbitor鉀代謝障礙酸堿平衡紊亂第26頁(yè)3.alterationsofmetabolismandfunction(1).effectonneuromuscularexcitability:(2).effectsonheartcardiacexcitability↑→↓cardiacconductivity↓cardiacautomaticity↓cardiaccontractibility↓(3).effectontheacid-basebalanceacidosisparadoxicalalkalineurine鉀代謝障礙酸堿平衡紊亂第27頁(yè)

skeletalmuscle

＜8mmol/LRP(depolarization)excitabilitystabbing;tremor

＞8mmol/LRPinactivationofNa+channeldepolarizationparalysis鉀代謝障礙酸堿平衡紊亂第28頁(yè)heart(hyperkalemiaK+permeability)5.5-7mmol/L→RP→Eexcitability

7-9mmol/L→RP→ETwave;QTshortcardiacarrestPR

QT鉀代謝障礙酸堿平衡紊亂第29頁(yè)

Autorhythmicity:

K+outwardofphase4

SpontaneousdepolarizationheartrateConductivity:RPNa+inwardofphase0conductivityconductiveblock

unidirectionalblockContractility:inhibitionofCa2+inwardflowcontractilityacid-basebalanceacidosisparadoxicalalkalineurine鉀代謝障礙酸堿平衡紊亂第30頁(yè)4.principlesofpreventionandtreatmenttreatmentofprimarydiseasedecreaseuptakeofK+cutdowntotalamountofbodypotassiumdialysision-exchangeresininduceK+uptakebycells.applicationofcalciumandsodium鉀代謝障礙酸堿平衡紊亂第31頁(yè)SummaryNormalpotassiummetabolismandregulationHypokalemiahyperkalemiadefinitioncausesalterationsofmetabolismandfunctionprinciplesofpreventionandtreatmentCasepresentation鉀代謝障礙酸堿平衡紊亂第32頁(yè)

ThepHoftheECFismaintainedwithinthenarrowrangeof7.35~7.45

<6.9or>7.8

!!!鉀代謝障礙酸堿平衡紊亂第33頁(yè)I.Acid-basehomeostasis

1.Theacidsandbasesintheblood

1)Acids

鉀代謝障礙酸堿平衡紊亂第34頁(yè)①Respiratoryacid(Volatileacid)

—H2CO3

CO2+H2O

H2CO3

H++HCO3-

鉀代謝障礙酸堿平衡紊亂第35頁(yè)

②Metabolicacid

Theproductofmetabolismofaminoacid:

phosphophoryn,nuclericacid→phosphoricacid

methionine,cysteine→sulfuricacid

purine→uricacid(gout)

Lacticacid(TheliverremovesandconvertstoG)

Ketoacids(pyruvicacid,acetoaceticacid,

β–hydroxybutyricacid)鉀代謝障礙酸堿平衡紊亂第36頁(yè)

2)Base

Thefruitsandvegetablesarerichinalkalisalt,e.g.sodiumcitrate,potassiumcitrate.

鉀代謝障礙酸堿平衡紊亂第37頁(yè)2.ControlofpH

1)Thebuffersystems

BuffersarethefirstdefenseagainstpHdisorders,andactimmediately.

Alkalisaltoftheacid

Buffersystem:————————————————

Weakacid

鉀代謝障礙酸堿平衡紊亂第38頁(yè)NaHCO3

————Bicarbonatebufferpair

H2CO3

Tobuffermetabolicacid

and

base

in

ECF

Hbbufferpairs

in

RBC

tobuffer

respiratoryacid.

HPO42-

————

Phosphatebufferpair

H2PO4-TobufferinICF

鉀代謝障礙酸堿平衡紊亂第39頁(yè)2)Respiratorycontribution

TherespiratorysystemistheseconddefenseagainstpHdisorders,andneedsseveralminutes.

↑H2CO3┑

┃

↑Therateanddepth↓H2CO3

↑[H+]┛

ButwhenPaCO2>80mmHg,↓therateanddepth.

↓H2CO3┑

┃

↓Therateanddepth↑H2CO3

↓[H+]┛鉀代謝障礙酸堿平衡紊亂第40頁(yè)3)Renalcontribution

Thekidneyisthethirddefenseagainstacid-basedisorders.

↑Metabolicacid→↑Excretionofacid

↑Reabsorptionofbase

↓Metabolicacid→↓Excretionofacid

↓Reabsorptionofbase

↑Base→↓Excretionofacid

↑Excretionofbase

鉀代謝障礙酸堿平衡紊亂第41頁(yè)

Thekidneyscancompensatefor

respiratoryacidimbalancesby

excretionofmetabolicacids.(Indirectly)

↑H2CO3→↑Excretionofmetabolicacid

↓H2CO3→↓Excretionofmetabolicacid

鉀代謝障礙酸堿平衡紊亂第42頁(yè)

Therenalcompensationrequiresseveraldaystobefullyeffective.

鉀代謝障礙酸堿平衡紊亂第43頁(yè)

4)EffectsofK+andCl-onpHregulation

Acidosiscancausehyperkalemia,

andalkalosiscancausehypokalemia.

H+

K+

HCO3-

Cl-鉀代謝障礙酸堿平衡紊亂第44頁(yè)3.ThedeterminationofpH

pH=pKa+log[HCO3-]

/[H2CO3]

Iftheratiois20:1,thepHwillbe7.4

鉀代謝障礙酸堿平衡紊亂第45頁(yè)4.Themainindicatorsoflaboratoryaboutacid-basebalance

1)pH:Thenormalrangeis7.35~7.45

AnormalrangeofpHrepresents

①Nodisturbanceinacid-basebalance

②Acid-baseimbalancewithcompletecompensation

③AmixedacidosisandalkalosiswhichhaveoppositeeffectonpHandoffseteachother.3situations:鉀代謝障礙酸堿平衡紊亂第46頁(yè)

2)PaCO2:Normalrangeis38~42mmHg(40mmHg).

(33~46mmHg)

PaCO2isanindicatoroftheeffectivenessofrespiratoryexcretingofcarbonicacid.

If↑PaCO2,meanshypoventilation

ormetabolicalkalosisaftercompensation

↓PaCO2,meanshyperventilation

ormetabolicacidosisaftercompensation鉀代謝障礙酸堿平衡紊亂第47頁(yè)

3)HCO3-:Thenormalrangeis24~33mmol/L.Itisanindicatoroftherenalexcretionofmetabolicacid.

↓HCO3-meansanexcessofmetabolicacids(metabolicacidosisorrespiratoryalkalosisaftercompensation).

↑HCO3-meansadeficitofmetabolicacidsoranexcessofbase(metabolicalkalosisorrespiratoryacidosisaftercompensation).鉀代謝障礙酸堿平衡紊亂第48頁(yè)①StandardbicarbonateSB

(22～27mmol/L)②ActualbicarbonateAB

AB>SB,hypoventilation;AB<SB,hyperventilation

③BufferbaseBB

④

BaseexcessBE⑤CO2

combinepower（CO2CP）鉀代謝障礙酸堿平衡紊亂第49頁(yè)

4)AG(aniongap):AGdescribesthedifferencebetweenunmeasuredanion(UA)andunmeasuredcation(UC).

AG=Na+-(Cl-+HCO3-).

Thenormalrangeis10~

14mmol/L(12mmol/L).

鉀代謝障礙酸堿平衡紊亂第50頁(yè)II.Acid-baseimbalances

1.Metabolicacidosis

1)Concept:Metabolicacidosisreferstoaprimarydeficitinbasebicarbonate,thepHfalls.鉀代謝障礙酸堿平衡紊亂第51頁(yè)2)Causes:

(1)Increaseinmetabolicacids

①Excessproductionofmetabolicacids

E.g.fastingandstarvation,diabeticketoacidosis,lacticacidosis(shock,hypoxia,heartfailure,anemia).

②Decreasedlossofmetabolicacids

E.g.renalfailure,renaltubularacidosis-I

③

Overdoseofacidicmedicine(aspirin).

AGisincreased.鉀代謝障礙酸堿平衡紊亂第52頁(yè)

(2)Increaseinbicarbonateloss

E.g.

①Severediarrhea,intestinalfistulas

②

Renaltubularacidosis-II.

③OverdoseofNH4+,releasesHCl

AGisnormal.

鉀代謝障礙酸堿平衡紊亂第53頁(yè)3)Compensation:

(1)Buffersystemandcell

(2)Signsofcompensation

①

Kussmaulbreathing

②

Acidurine鉀代謝障礙酸堿平衡紊亂第54頁(yè)4)Manifestations

(1)Heartfailure:

①Hyperkalemia__cardiacarrhythmia

②Impairmyocardialcontraction

(2)Decreasedresponseofcapillarytocatecholamines__Shock

(3)Depressionofneuralfunction

Lethargy,disorderofconsciousness,coma.

(4)Changesofosseoussystem

Renalrickets腎性佝僂病,osteomalacia骨軟化癥鉀代謝障礙酸堿平衡紊亂第55頁(yè)4)Laboratoryfindings

↓pH,↓HCO3-,

↓PaCO2ifthereiscompensationofrespiratorysystem.

鉀代謝障礙酸堿平衡紊亂第56頁(yè)Casestudy:

Arterialblood:

pH7.21

PaCO226mmHg

PaO2108mmHg

HCO3-12mmol/L

Na+135mmol/L

K+2.0mmol/L

Cl-110mmol/L

Urine:

pH5.0鉀代謝障礙酸堿平衡紊亂第57頁(yè)(1)A36-year-oldmanwashospitalizedwitha3-dayhistoryoffeverandwaterydiarrhea.Thebloodpressureis90/60mmHg,thepulseis112/minute,therespiratoryrateis24/minute,andthetemperatureis37.5oC.Thelaboratoryresultswereobtained.

鉀代謝障礙酸堿平衡紊亂第58頁(yè)2.Respiratoryacidosis

1)Concept:RespiratoryacidosisisdefinedasadecreaseofpHinducedbyprimaryincreaseinplasma[H2CO3].鉀代謝障礙酸堿平衡紊亂第59頁(yè)2)Causes

Respiratoryacidosiscanoccurasanacuteorachronicdisorder.

(1)Acuterespiratoryacidosis

E.g.acuterespiratoryinfections,chestinjuries,pulmonaryedema.

(2)Chronicrespiratoryacidosis

E.g.chronicobstructivelungdisease,chronicbronchitis.鉀代謝障礙酸堿平衡紊亂第60頁(yè)3)Compensation:

Buffersystemandcell

4)Manifestations:

Headache,cardiacarrhythmiasandneurologicabnormalities.

Neurologicmanifestationsmaybemoreprominentinrespiratoryacidosisthaninmetabolicacidosis.“CO2narcosis”

Themechanism:鉀代謝障礙酸堿平衡紊亂第61頁(yè)

(1)CO2crossestheblood-brainbarrierrelativelyeasily,andcandilatethebloodvesselsinthebrainandleadtobrainedema.

(2)CO2canalsodecreasethepHofthecerebrospinalfluid,andmakedepressionofneuralfunction,likeweakness,confusion,paralysis,stuporandcoma.鉀代謝障礙酸堿平衡紊亂第62頁(yè)

5)Laboratoryfindings

↓pH,↑PaCO2,

↑HCO3-ifthereiscompensationofkidneys(chronic).

鉀代謝障礙酸堿平衡紊亂第63頁(yè)3.Metabolicalkalosis

1)Concept:Metabolicalkalosisreferstoaprimaryincreaseinbasebicarbonate,thepHelevates.

2)Causes:

(1)DecreaseofacidE.g.vomiting

(Ileus:intestinalobstruction).

(2)IncreaseofbaseE.g.antacids,transfusionwithcitratedblood,hyperaldosteronism.

Saline-responsivealkalosisandsaline-resistantalkalosis鉀代謝障礙酸堿平衡紊亂第64頁(yè)3)Compensation

4)Manifestations

Alkalosiscancauseincreasedexcitabilityofnervoussystem,likehyperactivereflexes,musclehypertonicity,tetanyetc.

鉀代謝障礙酸堿平衡紊亂第65頁(yè)5)Laboratoryfindings

↑pH,↑HCO3-,

↑PaCO2

ifthereiscompensationofrespiratorysystem.鉀代謝障礙酸堿平衡紊亂第66頁(yè)4.Respiratoryalkalosis

1)Concept:RespiratoryalkalosisisdefinedasanincreaseofpHinducedbyprimarydecreaseinplasma[H2CO3].

2)Causes:Hyperventilation

E.g.anxiety,hysteria,fever,earlysalicylate(aspirin)toxicity,misuseofmechanicalventilation.鉀代謝障礙酸堿平衡紊亂第67頁(yè)3)Compensation

4)Manifestations

Tetany

5)Laboratoryfindings

↑pH,↓PaCO2,

↓HCO3-(dependonthenormalrenalfunction).鉀代謝障礙酸堿平衡紊亂第68頁(yè)5.Mixedacid-baseimbalances

Concept:Twoormoreprimaryacid-bas