Biochemistry

Question 1

sodium exists in which fluid compartment?

Answer 1

ECF

Question 2

AVP is another word for…

Answer 2

ADH

Question 3

what does aldosterone do?

Answer 3

retains Na in an effort to retain water

Question 4

the Na in a dehydrated urine sample would be low/high

Answer 4

low

Question 5

describe the H20 and Na in SIADH

Answer 5

high H20 
low Na (kidneys trying to get rid of sodium because of low water)

Question 6

what substances can mimic hyponatraemia and cause pseudohyponatraemia?

Answer 6

higher proteins and lipoproteins

Question 7

patient with really low Na who is fine…

Answer 7

pseudohyponatraemia

Question 8

decreased blood volume stimulates the release of what substances

Answer 8

aldosterone

ADH

Question 9

renal excretion of sodium is a key mechanism by which the kidneys regulate blood volume T or F

Answer 9

T

Question 10

what test distinguishes between central and nephrogenic DI?

Answer 10

DDAVP

Question 11

name the mechanism by which ADH regulates water conc

Answer 11

countercurrent multiplication

Question 12

what is DDAVP?

Answer 12

exogenous ADH

Question 13

nephrogenic/central DI will not respond to DDAVP

Answer 13

nephrogenic

Question 14

what is the problem in primary adrenal sufficiency?

Answer 14

cant make mineralocorticoids eg aldosterone so low Na

Question 15

ADH causes inc water absorption/excretion

Answer 15

absorption

Question 16

ADH also acts on what structures other than kidneys?

Answer 16

blood clotting
anxiey stress
blood vessel constriction and dilatation

Question 17

how much steroid do you need to regulate the HPA axis per day

Answer 17

7.5mg

Question 18

patients with what condition are less likely to retain Na than other subjects

Answer 18

primary adrenal insufficiency eg addisons

Question 19

ACTH only acts on the cortex T or F

Answer 19

T

Question 20

commonest cause of addisons

Answer 20

autoimmune

Question 21

synacthen test measures…

Answer 21

give ACTH and see if cortisol levels increase

Question 22

how can you determine between primary and secondary adrenal sufficiency?

Answer 22

measure ACTH levels

Question 23

parathyroid glands stimulate DIRECT Ca absorption where?

Answer 23

bone

kidneys

Question 24

parathyroid glands stimulate Ca absorption INDIRECTLY where? how does it do this?

Answer 24

gut via vitamin D

Question 25

secondary hyperparathyroidism results from pitiitary stimulation of the parathyroid glands T or F

Answer 25

F! pituitary has no control over parathyroid

Question 26

hypercalcaemia interferes with absorption where in the kidney? what happens as a result?

Answer 26

PCT

low Na

Question 27

most common cause of hyperkalaemia

Answer 27

renal failure

then haemolysis then drugs eg spirinolactone

Question 28

what is the main difference appearance-wise of SIADH compared to hyponatraemia

Answer 28

patient won’t be dry

Question 29

first line Tx SIADH

Answer 29

fluid restriction

Question 30

diagnostic features of SIADH

Answer 30

“wet” patient

high urine osmolality

Question 31

Ix cushings syndrome

Answer 31

short and long synacthen test

Question 32

Ix cushings disease

Answer 32

dexamethasone suppression test

Question 33

what level is the hallmark of tumour lysis syndrome?

Answer 33

high urate