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Transcript of L’analyse d’urine et les glomerulon é phrites Dr Tim Meagher ExamOne Canada AQTV, Qu é bec,...
L’analyse d’urine et les L’analyse d’urine et les glomerulonglomerulonééphritesphrites
Dr Tim MeagherDr Tim Meagher
ExamExamOOne Canadane Canada
AQTV, QuAQTV, Quéébec, 2008bec, 2008
L’analyse d’urineL’analyse d’urine
ApparenceApparence gravitgravité spécifiqueé spécifique Cellules: leucocytes, globules rouges Cellules: leucocytes, globules rouges hhéémoglobinemoglobine ProtProtééinesines bactbactérieséries Cylindres, rouges, blancs, hyalineCylindres, rouges, blancs, hyaline
GravitGravité spécifiqueé spécifique
Une mesure de concentrationUne mesure de concentration Plus l’urine est concentrPlus l’urine est concentré plus la GS est é plus la GS est
elevéelevé Plus l’urine est diluPlus l’urine est dilué plus la GS est basé plus la GS est bas La GS dLa GS dépend desépend des tubules tubules
HHéématuriematurie
Globules rouges ou hGlobules rouges ou héémoglobinemoglobine Gloubules rouges proviennent du rein Gloubules rouges proviennent du rein
ureturetère, véssie ou prostateère, véssie ou prostate > 5 m> 5 mééritent une investigationritent une investigation
LeucocytesLeucocytes
PyuriePyurie proviennent du rein, uretproviennent du rein, uretère, véssie, ère, véssie,
prostate, ou urèthreprostate, ou urèthre Cystite Cystite Peuvent etre assures sans investigationPeuvent etre assures sans investigation
BactBactérieséries
DDénotent inflammationénotent inflammation Infection (cystite, pyelonéphrite)Infection (cystite, pyelonéphrite) Néphrite interstitielleNéphrite interstitielle
– Medicaments, rMedicaments, réaction allergiqueéaction allergique Asymptomatique ou symptomatiqueAsymptomatique ou symptomatique AccompagnAccompagnées de globules blancsées de globules blancs
Cylindres (casts)Cylindres (casts)
Sont des ‘empreintes’ des tubulesSont des ‘empreintes’ des tubules Proviennent des reinsProviennent des reins D’importance variD’importance variéeée Bénins: hyalines, granulaires en petite Bénins: hyalines, granulaires en petite
quantitéquantité Pathologies importantes: granulaires en Pathologies importantes: granulaires en
grande quantité, RBC castsgrande quantité, RBC casts
Protein comes in many sizesProtein comes in many sizes
Size is described in ‘molecular weight’Size is described in ‘molecular weight’ Low molecular weight (small)Low molecular weight (small)
– Light chainsLight chains Medium molecular weight (medium)Medium molecular weight (medium)
– Need an exampleNeed an example High molecular weight (large)High molecular weight (large)
– albuminalbumin
How does kidney handle protein?How does kidney handle protein?
FiltersFilters ReabsorbsReabsorbs Minimally excretesMinimally excretes
Urinary proteinUrinary protein
Some protein is normal!Some protein is normal!– 150 mgs in 24 hours150 mgs in 24 hours
» 10-15 mgs is albumin10-15 mgs is albumin
» Small sized plasma proteinsSmall sized plasma proteins
» Pieces of renal cells Pieces of renal cells
‘‘Proteinuria’ is an Proteinuria’ is an abnormalabnormal amount of amount of protein in urine, protein in urine, – ie > 150 mgs in 24hrs.ie > 150 mgs in 24hrs.
Detecting protein in urineDetecting protein in urine
Dipstick (used in physician offices)Dipstick (used in physician offices)– Trace, 1+, 2+, 3+Trace, 1+, 2+, 3+
» False positive situations existFalse positive situations exist High specific gravity (very concentrated urine)High specific gravity (very concentrated urine) Very alkaline urineVery alkaline urine
» False negative situations existFalse negative situations exist Very low specific gravity (very dilute urine)Very low specific gravity (very dilute urine)
Rule of thumbRule of thumb– Protein level (mgs %) should not exceed SG (last 2 digits)Protein level (mgs %) should not exceed SG (last 2 digits)
» Eg if SG is 1.022, protein should be < 22 mgs%Eg if SG is 1.022, protein should be < 22 mgs%» If SG 1.30 protein should be < 30 mgs%If SG 1.30 protein should be < 30 mgs%
(IV) MEASURING PROTEINURIA
Semiqualitative (Dipstix)
Trace1+2+3+4+
Quantitative
10 - 30 mg/dL31 - 50 mg/dL
51 - 125 mg/dL126 - 300 mg/dL301 mg/dL & up
Detecting protein in urine (2)Detecting protein in urine (2)
QuantitativeQuantitative– Spot measurement- usually recorded in mgs% Spot measurement- usually recorded in mgs%
or mmol/Lor mmol/L– 24 hour urine collection24 hour urine collection
» Measure protein and creatinineMeasure protein and creatinine Cumbersome, inconsistent and unreliableCumbersome, inconsistent and unreliable < 1G creatinine excreted: likely an incomplete collection< 1G creatinine excreted: likely an incomplete collection
Contaminants
<1% Paraproteins
Albumin
Sloughed Renal Cells
RBCs, WBCs
PROTEINURIA (INSURANCE POPULATION)
viz. 60% of cases of increasedprotein in urine in insurancepopulation = due to increasedalbumin
Detecting protein in urine (3)Detecting protein in urine (3)
protein/ creatinine ratioprotein/ creatinine ratio– Independent of specific gravity or urinary Independent of specific gravity or urinary
volumesvolumes– > 0.2mgs/ G creatinine is abnormal> 0.2mgs/ G creatinine is abnormal
» 0.2-1.5 suggests tubular disease0.2-1.5 suggests tubular disease
» > 1.5 suggests glomerular disease> 1.5 suggests glomerular disease
Detecting protein in urine (4)Detecting protein in urine (4)
Albumin/creatinine ratioAlbumin/creatinine ratio– Proteinuria may be due to non-renal sourcesProteinuria may be due to non-renal sources
» Prostate, vaginal. RBC’s WBC’sProstate, vaginal. RBC’s WBC’s
– albuminuria is specific for renal diseasealbuminuria is specific for renal disease» < 30mgs / 24 hours is N (< 3 mgs%)< 30mgs / 24 hours is N (< 3 mgs%)
» ‘‘Microalbuminuria’Microalbuminuria’ is 30-300 mg/24h. (3-30mgs%) is 30-300 mg/24h. (3-30mgs%)
» ‘‘Macroalbuminuria’Macroalbuminuria’ is > 300 mg/24h. (> 30mgs%) is > 300 mg/24h. (> 30mgs%)
– Albumin/ creatinine ratio > 0.3 is Albumin/ creatinine ratio > 0.3 is abnormalabnormal
Measuring urinary albuminMeasuring urinary albumin
Albumin Albumin (mgs/dl)(mgs/dl)
Alb/creat Alb/creat (mgs/G)(mgs/G)
Alb/creatAlb/creat
mgs/mmolmgs/mmol
24h. urine 24h. urine albumin albumin (mgs)(mgs)
NormalNormal < 3< 3 < 30< 30 < 2.5< 2.5 < 30< 30
MicroalbMicroalb < 30< 30 30-30030-300 2.5-252.5-25 30-30030-300
MacroalbMacroalb > 30> 30 > 300> 300 > 25> 25 > 300> 300
Why measure albumin in urine?Why measure albumin in urine?
Better index of glomerular diseaseBetter index of glomerular disease As glomerular disease progresses As glomerular disease progresses
albuminuria appears first. This is called albuminuria appears first. This is called ‘microalbuminuria’‘microalbuminuria’
As amount of albumin increases we use the As amount of albumin increases we use the term ‘macroalbuminuria’ or ‘proteinuria’ term ‘macroalbuminuria’ or ‘proteinuria’ (as dipstick for protein is now positive)(as dipstick for protein is now positive)
Benign proteinuriasBenign proteinurias
Intermittent proteinuriaIntermittent proteinuria Postural or ‘orthostatic’Postural or ‘orthostatic’
– N supine; elevated when uprightN supine; elevated when upright Exercise-inducedExercise-induced Febrile illnessesFebrile illnesses Contaminants: seminal, prostatic, vaginal Contaminants: seminal, prostatic, vaginal
fluidsfluids
Pathologic proteinuriasPathologic proteinurias
Constant proteinuriasConstant proteinurias– > 1/3 specimens (insurance)> 1/3 specimens (insurance)– > 3 months duration (clinical)> 3 months duration (clinical)
AlbuminuriaAlbuminuria– MicroalbuminuriaMicroalbuminuria– MacroalbuminuriaMacroalbuminuria
Bence-Jones proteinuriaBence-Jones proteinuria
Don’t jump to conclusions!Don’t jump to conclusions!
Albumin levels varyAlbumin levels vary– posture, exercise, fever, otherposture, exercise, fever, other
Creatinine levels varyCreatinine levels vary– Handling delays reduce urine creatinineHandling delays reduce urine creatinine– creatinine production decreases with creatinine production decreases with
» Increasing ageIncreasing age» Older women in particularOlder women in particular
50% of abnormal results will be normal with re-50% of abnormal results will be normal with re-testing!testing!
Significant proteinuiasSignificant proteinuias
GlomerularGlomerular– Glomerulus is ‘leaky’Glomerulus is ‘leaky’– Too many proteins are making way into tubuleToo many proteins are making way into tubule
TubularTubular– Tubules are not reabsorbingTubules are not reabsorbing
overflowoverflow– Capacity of tubules to reabsorb is overwhelmedCapacity of tubules to reabsorb is overwhelmed– Tubules are working normallyTubules are working normally
structure of glomerulusstructure of glomerulus
arteriole
collecting duct
to bladder
normal glomerulus