Exames Flashcards
Sedimento urinário como biomarcador de dc renal
Leukocyturia
- Definedas>3WBCs/hpfonmicroscopy
- Mostcommonlyrelatedtoinfection
- Sterilepyuriaaffectsupto14%ofwomenand 2.6% of men
- Evaluationdirectedbythepresenceor absence of symptoms and/or renal dysfunction
Sterile Pyuria: Infection Related
Current Antibiotic Use
Recently treated UTI
Gynae infection
Urethritis due to gonorrhea, chlamydia, mycoplasma or ureaplasma
Prostatitis/Balanitis
GU Tuberculosis
Parasitic infection, eg schistosomiasis or trichomoniasis Appendicitis
Sterile Pyuria: Non Infection Related
Urinary catheterization
Recent instrumentation
Renal calculi
Renal transplant rejection
Neoplasia Interstitial nephritis Papillary necrosis
Pelvic irradiation Urinary fistula
PKD Glomerulonephritis Interstitial cystitis Renal vein thrombosis
Cilindros leucocitarios
Indicative of intra-renal inflammation
• Typically associated with interstitial inflammation
• Many types of glomerulonephritis
• Important considerations include AIN, pyelonephritis
Hematuria
- Urinedipstick:Positiveinthepresenceof RBCs, Hb or myoglobin
- Urinemicroscopy:>2RBCsperhpf
Hematuria
Glomerular Bleeding: >5% acanthocytes seen by phase contrast
Specificity 98% Sensitivity 52%
false positives
• Spun urine in true hematuria : supernatant clear, pellet red
• Red supernatant with dipstick positive – Lysed RBCs (dilute urine)
– Myoglobinuria
– Hemoglobinuria
• Red supernatant with dipstick negative
– Porphyria (acute intermittent porphyria,
hereditary coproporphyria & variegate porphyria)
– Beet ingestion
– Phenazopyridine
Differential Diagnosis of Isolated Hematuria
Glomerular
IgA nephropathy
Thin basement membranes
Familial nephropathies
Non-glomerular
Urologic malignancy (age) Nephrolithiasis
Cystic renal disease Papillary necrosis
Metabolic Abnormalities- Hypercalcuria/Hyperuricosuri a
Urinary tract infection
Cystitis including viral/hemorrhagic
Initial Evaluation
• Confirm(repeatsample)withmicroscopy
• CTurography
• Cystoscopy(esp>40yrsorriskfactors)
• Urinecytology(90%sensitivityforbladderca; poor for upper tract tumors)
Lipiduria
- Seeninnephroticsyndrome
- CanbeseeninPKDorrarelyinAIN
- FatdropletscanbeconfusedwithRBCsby light microscopy
- Differentiatedbytheirvariablesizeand dark outline
- ‘Maltesecrosses’underpolarizedlight
- Generallyassociatedwithglomerular disease
Urine sediment Analysis: Take Home Points II
Leukocyturia–ifunexplained,considerinfectious causes associated with negative cultures
• Urineeosinophilshavelittleutilityinthediagnosis of AIN
• Asymptomatichematuriaiscommonlyurological in origin in patients >40 years and repeat screening may be necessary
• Isolatedasymptomatichematuriaisassociated with increased risk of ESKD in long term follow up
- Alportsyndromeisadefectinα-3,α-4orα-5 chains of Type IV collagen in GBM
- ThinGBMisacarrierstateofrecessiveAlport (defect in α-3 or α-4)
- AKIinanticoagulatedpatients–thinkwarfarin- related nephropathy (also seen with NOACs)
- FattycastscanbeconfusedwithRBCcasts-use polarised light to see ‘maltese crosses’
Albuminúria
Proteinúria
Spot
• Albuminúria (amostra de urina) 30mg/g de creatinina
• PROTEINÚRIA
> 300 mg/g creatinina
ALBUMINÚRIA 30- 300 mg/g
Marcador de dano renal
• Fator de risco para progressão
• Possível marcador de permeabilidade vascular • Fator de risco para DCV
Biomarcador
MARCADOR DE DOENÇA RENAL E ENDOTELIAL
Albuminúria
Albuminúria
Creatinina
, it is an imperfect measure of kidney function
Reduction ofmuscle mass, as seen in amputees arid patients with malnutrition or muscle wa~ting, can result in a lower serum creatinine level without a corresponding change in GFR.
Younger persons, men, and black persons often have higher muscle mass and higher serum creatinine levels at a given level of GFR compared with older persons with decreased muscle mass. Patients with advanced liver ·disease produce lower levels of precursors of serum creatinine and
often have muscle wasting, with a correspondingly lower serum creatinine level at a particular level of GFR.
Finally, serum creatinine overestimates kidney function melderly per- sons, especially women.
Certain medications, including cimetidine and trimethoprim, block tubular secretion of creatinine and result in a higher serum creatinine level without a change in GFR.
The nephrotic syndrome is associated with increased tubular secre- tion ofcreatinine, leading to overestimation ofGFR The col- orimetric assay for serum creatinine cross-reacts with cefo:xitin, ilucyLUsine, a11d acetoacetate, leading to falsely high values. Elevated bilirubin levels interfere with the colorimetric assay, resulting in falsely low values of serum creatinine.
Creatinina
Creatinina
Vantagens
Detecção bioquímica simples e barata.
Produção endógena é constante em um mesmo indivíduo: metabolismo da creatina pelo músculo.
Valores normais de 0,6 a 1,3 mg/dL Inconvenientes
Variações na produção (Desnutrição ou perda de massa muscular, envelhecimento)
Não apresenta relação linear com a TFG Fontes de erro
creatinina
nVantagens
nDetecção bioquímica simples e barata.
nProdução endógena é constante em um mesmo indivíduo: metabolismo da creatina pelo músculo.
nValores normais de 0,6 a 1,3 mg/dL
nInconvenientes
nVariações na produção (Desnutrição ou perda de massa muscular, envelhecimento)
nNão apresenta relação linear com a TFG
nTem diferenças entre gêneros e etnias
tfg
nConceito de clearance
nSubstância filtrada livremente pelo glomérulo
nNão reabsorvida ou secretada
massa filtrada = massa excretada na urina
TFG .Px = V.Ux, onde V=fluxo urinário (ml/min)
TFG = V.Ux/Px
nPara medir a Taxa de Filtração Glomerular eu preciso:
n1) Dosar o ”marcador” no plasma
n2) Dosar o ”marcador” na urina
n3) Ter uma medida de fluxo urinário, ou seja, coletar urina em um período definido para poder calcular o fluxo urinário em ml/min….
casts
Urinary acanthocytes and red blood cell casts along with dipstick albuminuria are typically
indicative of glomerular injury.
renal tubular epithelial cells(RTECs), RTEC casts , and muddy browncasts (Fig 1C) points to ischemic or nephrotoxic (or combined) tubular injury. Culture-negative leukocy-turia, along with RTECs, white blood cell casts(Fig 1D), and granular casts, strongly suggests anacute or chronic tubulointerstitial disease in the proper clinical setting, such as exposure to a culprit drug or an underlying systemic illness. Other examplesinclude diagnostic urinary crystal casts con
rming thecause of kidney disease as a drug-induced or endog-enous crystalline nephropathy.
22
Oval fat bodies,cholesterol crystals, and fatty casts are usually indic-ative of nephrotic syndrome and lipiduria from anassociated glomerular disorder.
23,24
Thus, urine sedi-ment examination is a biomarker of kidney diseasethat may also be diagnostic of the nephron site of injur
FE DE NA
FENA = NAU XCREAT SERICA/NASERICO X CREAT URINARIA X 100
The fractional excretion of sodium (FENa) measures the percentage of sodium which is actually excreted through the urine over the total sodium originally filtrated by the kidney. The majority of the sodium is reabsorbed. however, if the patient is not receiving diuretics and the FENa is less than 1%, it means that the kidney is avidly trying to preserve sodium. On the contrary, if the kidney is in acute renal failure and the FENa is higher than 1% (in the absence of diuretics), this may mean that there is tubular damage.
Renal Clearanc
eVolume of plasma that is cleared of a substance per minute
Clearance of a substance X = UXV/ PX
UX: Concentration of substance in urine
PX: Concentration of substance in plasma
V: Urine flow rate in mL/min
