Biochemistry

Question 1

What are the positive points for inulin as a measure of GFR?

Answer 1

Constant rate
Freely filtered at glomerulus
Not reabsorbed 
Not secreted
No extra-renal eliminiation

Question 2

Why is inulin not used?

Answer 2

It would need to be inputted as oral/injectible form and wait for it to be metabolised.
Hard to measure

Question 3

What is urea?

Answer 3

End of product of protein metabolism

Question 4

Where does the urea cycle occur?

Answer 4

in liver

Question 5

Why is urea not suitable for eGFR ?

Answer 5

One quarter of elimination does not occur in kidneys

Question 6

What will increase urea output?

Answer 6

Heavy protein intake

Question 7

What is creatinine?

Answer 7

Product of muscle breakdown

Question 8

Why is creatinine not a perfect marker for GFR?

Answer 8

Small amount is secreted by distal tubule

Question 9

What is the normal for GFR?

Answer 9

120

Question 10

What is the maximum number given for eGFR?

Answer 10

60.

Harder to measure in bigger numbers

Question 11

What is the issue with using creatinine as a marker of GFR?

Answer 11

Not sensitive to changes in GFR until it is significantly reduced

Question 12

What is clearance?

Answer 12

The volume of plasma that is cleared of a specific substance per minute

Question 13

How is urinary creatinine clearance worked out?

Answer 13

[creatinine]urine X urine volume / [creatinine]serum x duration of collection

Question 14

What factors impact on serum creatinine?

Answer 14

Muscle mass
Age
Sex
Diet
Ethnicity

Question 15

If a very accurate eGFR is necessary then what is used?

Answer 15

Chromium- EDTA

Question 16

What is the gold standard for measuring proteinuria?

Answer 16

24 hour collection

Obviously not practical

Question 17

What test can be done relatively simply for proteinuria?

Answer 17

Protein:creatinine ratio

Question 18

How much protein must be excreted/day to be significant?

Answer 18

Over 150mg

Question 19

What is overflow proteinuria?

Answer 19

Proteinload is too much and kidney cannot reabsorb all of it.

Question 20

When is overflow proteinuria common?

Answer 20

Multiple myeloma

Question 21

What is glomerular proteinuria?

Answer 21

A normal amount of protein but the glomeruli do not filter it and cannot all be reabsorbed

Question 22

What is tubular proteinuria?

Answer 22

Microglobulins usually go through the glomeruli but in tubular they are not reabsorbed

Question 23

What is a key histological sign of multiple myeloma?

Answer 23

Eccentric nucleus.

Nucleus not in centre

Question 24

What is multiple myeloma?

Answer 24

Malignancy is uncontrolled multiplication of B lymphocytes to make immunoglobulins

Question 25

What is sometimes described on x-ray with multiple myeloma?

Answer 25

Pepper pot appearance in skull

Question 26

What is microalbuminuria?

Answer 26

Excretion of albumin, below limits of protein detention by dipstick

Question 27

What can microalbuinuria be a sign of?

Answer 27

Diabetic nephropathy

Question 28

If hypertensive and microalbuminuria then what drug is given?

Answer 28

ACEI

Question 29

What 3 classes of pathology can cause oliguria?

Answer 29

Pre-renal
Renal
Post renal

Question 30

Give an example of a pre-renal issue

Answer 30

Reduced renal perfusion e.g. hypovolaemia

Question 31

Give an example of a renal cause of oliguria

Answer 31

Intrinsic kidney damage e.g. glomerulonephritis

Question 32

Give an example of a renal cause of oliguria

Answer 32

Ureteric obstruction e.g. stones or malignancy

Question 33

What biochemical measurements are necessary to figure out the cause of oliguria?

Answer 33

Urine osmolality

Serum osmolality