医学优质课件精选——《肾功能检验》.ppt

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1、,肾功能检验,执教教师：XXX,Anatomy of Kidney,Functions of the kidney,Excretion of Metabolite Waste: urea, uric acid, creatinineUrine Production, regulation of homeostasis, water, acid base balanceEndocrine Function: renin, erythropoietin, 1,25 -dihydroxycholecalciferol,Renal function tests,Detect renal damageM

2、onitor functional damageDistinguish between impairment and failure,Kidney Function,A plumbers view,How do you know its broken?,NO Urine!Clinical symptomsTests,Where can it break?,Pre-renalRenalPost-renal,Laboratory tests of renal function,Glomerular Function TestsRenal Tubular Function Tests,Section

3、 1 Investigation of Glomerular Function,Renal Blood Flow: 1200-1400ml/minRenal Plasma : 600-800ml/min20% of plasma: glomerular filtration GFR:Glomerular Filtrtion Rate Concept,Renal Clerance,Concept Virtual volume of plasma from which the substance in question has been completely removed during a gi

4、ven time interval. C=UV/P U:urine concentrtion P:plasma con. V:urine flow rate,Usefulness of Renal Clerance,Freely filtrated, neither secreted, nor reabsorbed: Inulin: GFR DeterminationFreely Filtrated, small amounts secreted, without reabsorption: Cretinine:GFRFree filtrated, completely reabsorptio

5、n: Glucose Tubular Maxima Reabsorption Rate,Inulin Clerance,Polymer of fructoseMW:5500Free filtration, without secretion and reabsorptionGFRMethod Reference Interval: 2.0-2.3ml/min,Endogenous Creatinine Clearance,100g,98% stored in musle,MW:113Cretine phosphate-cretinecretinineFreely filtration, sma

6、ll mounts: secretionExogenous and Endogenous CreatinineGrossly Investigate the GFR,Method 24h urine collection method modified 4h urine collection method Clerance Correction： Ccr x SBSA/IBSA,Plasma urea,Secreted and reabsorbed by tubules, freely filtratedquick, simple measurementwide reference range

7、 3 - 8 mmol/Lsensitive but non-specific index of illness,Urea excretion,filtered at glomerulusabout 40% filtered urea is reabsorbed by renal tubules in healthmore urea is reabsorbed if rate of tubular flow is slowtubular flow rate is slow when there is renal hypoperfusion,Increased plasma urea,GI bl

8、eedtraumarenal hypoperfusiondecreased RBFdecreased ECFV,acute renal impairmentchronic renal diseasepost-renal obstructioncalculustumour,Urea,Useful test but must be interpreted with great careAlways consider input, output and patients fluid volume,Plasma creatinine,50 - 140 umol/Lincreases in concen

9、tration as GFR decreasesanalytical interferences (acetoacetate - DKA)NOT proportional to renal damage,Plasma Creatinine,GFR,pCreat,140 mL/min,0 mL/min,Change within an individual patient is usually more important than the absolute value,Plasma creatinine in chronic renal disease,May increase to 1000

10、 umol/LPlot of recipricol of plasma creatinine concentration predicts when intervention is required in end stage renal failure,Plasma Uric Acid,20%:foods;80%:purine metabolismSmall amounts: conjugated with albuminFree Filtrated,98%-100%:reabsorbedPlasma UA concentration: depend on glomerular filtrat

11、ion and tubular reabsorption,Progression of chronic renal disease,Plasma Cystatin C,Cysteine proteinase inhibitorProduced by nucleated cellsMW:13000, free filtration,reabsorbed and metabolized by tubulesPlasma CysC concentrtion: depend on glomerular filtration,Carbamylated hemoglobin,Ureabloodcyanat

12、eHb carbamylatedCarHbARF：no changes(1 weeks)CRF: increase,Laboratory tests of renal function,glomerular filtration rate impracticalcreatinine clearance unreliableplasma creatinine specific but insensitiveplasma urea subject to problemsurine volume often forgotten!,Section 2 Investigation of Tubular

13、Function,Distal nephron Function tests 1. Mosenthal test Concentration dilution test 8 AM :Voiding and Discarded 10,12,14,16,18,20:00 and 8:00 next day: collecting urine samples Determing the urine volume and gravity,2.Urine Osmolarity3.Acute Oliguria Prenal? Renal?,Proximal tubular Function tests 1

14、.Low MW proteins in urine 2.Tubular maximal glucose reabsorption 3.Tubular maximal PAH secretion 4.Amino acide in urine Fanconi Syndrome,Section 3 Effective Renal Blood Flow,Isotope Method:131I-OIHPAH Clearance: 20%:filtrated,80%:secreted by tubules,Section 4 Investigation of renal tubular acidosis,

15、Tubular Acidosis:I,II,III.IVI:distal formII:proximal form,NH4Cl Loading Test,Oral administration of NH4ClArtificial Metabolic AcidosisUrine Sample CollectionpH determination,Fraction of HCO3- excretion,HCO3-:85-90%: reabsorbed by proximal tubules; 10-15%: reabsorbed by distal tubulesOral Administration of NaHCO3Urine CollectionDetermination of PCr,UCr,PHCO3,UHCO3Caculation: FEHCO3=UHCO3.PCr/UCr.PHCO3,谢谢观看,请指导,