Renal - Urine, Urea And Creatinine Flashcards Preview

Year 3 Medicine COPY > Renal - Urine, Urea And Creatinine > Flashcards

Flashcards in Renal - Urine, Urea And Creatinine Deck (9)
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1
Q

Urine - renal causes of haematuria

A
  • Congenital: PCK disease
  • trauma
  • infection: pyelonephritis
  • neoplasm
  • immune: GN/TIN
2
Q

Urine - extra renal causes of haematuria

A
  • Trauma: stones, catheter
  • infection: cystitis, prostatitis, urethritis
  • neoplasm: bladder/prostate
  • bleeding diathesis
  • drugs: NSAIDs, furosemide, ciprofloxacin, cephalosporins

*Can get false positives from myoglobin or porphyria

3
Q

Proteinuria - commonest causes

A
  • DM
  • Minimal change glomerulonephritis
  • Membranous glomerulonephritis
  • Amyloidosis
  • SLE

Other more rare:
-HTN, TIN, UTI, fever

*False negatives: Bence-Jones protein

4
Q

What is microalbuminuria and what are the causes?

A
  • Albumin: 30-300mg/24h in urine

- Causes: DM, HTN, minimal change GN

5
Q

What are the 3 different urine casts indicative of?

A
  • RBC: glomerular haematuria
  • WBC: interstitial nephritis or pyelonephritis
  • Tubular: ATN
6
Q

What is creatinine and that is it’s relationship to GFR?

A
  • synthesised during muscle turnover
  • freely filtered and small proportion secreted by PCT
  • Plasma Cr does not rise above normal until there is a 50% drop in GFR
7
Q

What is urea? What makes it higher/lower and what affects its reabsorption?

A
  • Produced from ammonia by liver in ornithine cycle
  • Raised with protein meals (upper GI bleed/supplements)
  • Lowered in hepatic impairment
  • Re-absorption is dependent on urine flow. Low flow = high urea reabsorption (eg dehydration). Body can reabsorb between 10-70% of urea produced, rest is excreted.
8
Q

How would you interpret

  • Isolated raised urea
  • Both urea and creatinine raised
A
  • Decreased flow (hypoperfusion/dehydration)

- Decreased filtration- ie renal failure

9
Q

How do you calculate eGFR and what are the problems associated with it?

A
  • Equation based on serum Cr, sex, age and race
  • Problems: good for pts with established renal failure (but not as applicable to general population), too pessimistic in mild renal impairment, most old people are in CKD >=3 so eGFR may not be super useful or lead to over Rx