6: Biochemistry of renal disease Flashcards Preview

Renal Week 2 2017/18 > 6: Biochemistry of renal disease > Flashcards

Flashcards in 6: Biochemistry of renal disease Deck (24)
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1
Q

Why is inulin a good marker for GFR?

A

Freely filtered

Not reabsorbed

Not secreted

2
Q

Why isn’t inulin always used as a marker for GFR?

A

Needs to be injected into patient

3
Q

Why isn’t urea used as a marker of GFR?

A

Recycled in kidneys and reabsorbed in GI tract - so GFR isn’t constant

4
Q

Which natural substance is used as a marker of GFR?

What’s the one caveat?

A

Creatinine

Small amount secreted into the tubules from capillaries, so can overestimate GFR

5
Q

As GFR decreases, what happens to [creatinine] of the plasma?

A

Increases

As kidneys can’t filter it

6
Q

At high GFRs, [creatinine]serum (is / isn’t) useful for estimating kidney function.

A

isn’t sensitive at high GFRs

only sensitive when GFR is low

7
Q

What is clearance?

A

Volume of plasma cleared of a substance PER MINUTE

8
Q

What two factors affect your creatinine levels?

A

Muscle mass

Diet

9
Q

Because a biochemist can’t gauge a patient’s muscle mass and diet off of a sheet of paper, what is used to estimate their creatinine production instead?

A

Age

Sex

Ethnicity

10
Q

What is the difference between GFR and eGFR?

A

eGFR modified based on age, sex and ethnicity

As these can affect creatinine production rates

11
Q

Which type of creatinine clearance is more sensitive?

What estimate is better than both of them?

A

Urinary creatinine > Serum creatinine

eGFR

12
Q

How can the degree of proteinuria be estimated?

A

24h urine protein collection (gold standard)

Protein/creatinine ratio (more convenient, less accurate)

Urinalysis (even more convenient, least accurate)

13
Q

What excretion of protein is an indicator of severe glomerular damage?

A

> 150 mg/day

14
Q

What is biopsied to diagnose multiple myeloma?

A

Bone marrow

15
Q

What type of proteinuria is caused by multiple myeloma?

Which type of protein accumulates?

A

Overflow proteinuria

Bence-Jones protein

16
Q

What type of renal syndrome is seen when the glomeruli are very leaky to proteins?

A

Nephrotic syndrome

17
Q

What are the signs of nephrotic syndrome?

A

Proteinuria

Fluid retention and oedema - (pitting) oedema

Hypoalbuminaemia

Hyperlipidaemia

18
Q

What is microalbuminaemia?

A

Proteinuria in levels undetectable by a urinalysis dipstick

19
Q

Microalbuminaemia is the earliest sign of which disease in diabetics?

A

Nephropathy

20
Q

Which drugs can slow the progression of renal disease detected early by microalbuminaemia?

A

ACE inhibitors

ARBs

21
Q

What are some pre-renal causes of oligouria?

What is the mechanism?

A

Blood loss

Hypovolaemia e.g sepsis

Mechanism: decreased renal perfusion

22
Q

What are some post-renal causes of oligouria?

What is the mechanism of it?

A

Kidney stones

Malignancy

Blockage of urine flow

23
Q

What are some renal causes of oligouria?

A

Glomerulonephritis

Nephrotoxic substances

24
Q

If urine osmolality decreases, what is dysfunctional?

A

Renal tubules

not hyperconcentrating urine anymore