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Flashcards in Biochemistry Deck (40):
1

how are sodium and water controlled

Mineralocorticoid activity [sodium]
ADH release and action [water]

2

how is sodium controlled by mineralocorticoid activity

sodium retention in exchange for potassium and/or hydrogen ions

3

what happens if there is too much mineralocorticoid activity

sodium retention

4

what happens if there is too little mineralocorticoid activity

sodium loss

5

what does sodium loss result in

water loss

6

what is the main mineralocorticoid that influences sodium

aldosterone

7

what effects does an increase in ADH cause

concentrated urine
[high urine osmolality]

8

what affect does a decrease in ADH cause

dilutes urine
[low urine osmolality]

9

how does ADH work

acts on the renal tubules to cause water reabsorption

10

what can decreased sodium be due to

SIADH [too much water, decreased secretion]

Addison's disease [increased sodium loss via adrenal insufficiency]

11

what can increased sodium be due to

diabetes insipidus [increase water loss]
decreased water intake

12

what blood results are seen in addison's

low sodium
high potassium

13

what non-osmotic stimuli can cause the release of ADH

Hypovolaemia/hypotension
Pain
Nausea/vomiting

14

Tx for too little sodium

give sodium

15

Tx for too much water

fluid restrict

16

Tx for too little water

give water

17

Tx for too much sodium

get rid of excess sodium (and water with it) e.g. diuretics

18

what are the 2 most important factors that determine potassium excretion

GFR
plasma potassium concentration

19

what ECG changes are seen in hyperkalaemia

tall tented T waves
widen of the QRS complexes

20

what are Sx of hyperkalaemia

cardiac arrest
muscle weakness
paraesthesia

21

what are the 3 categories of causes of hyperkalaemia

increased intake
redistribution
decreased excretion

22

what are causes of decreased excretion leading to hyperkalaemia

renal failure
- reduced GFR seen

hypoaldosteronism
- deficiency of aldosterone results in loss of sodium, decreased GFR with retention of potassium and hydrogen

23

what is the role of aldosterone in potassium absorption

stimulates sodium reabsorption at the expense of potassium and hydrogen

24

when is hyperkalaemia cause by hypoaldosteronism often seen

with the use of ACEi and ARB to treat HTN

25

what are causes of redistribution out of cells leading to hyperkalaemia

potassium release from damaged cells
- rhabdomyolysis, trauma

metabolic acidosis
- has hydrogen ions increase so do potassium ions

insulin deficiency
- insulin stimulates the uptake of potassium

26

Tx of hyperkalaemia

Calcium gluconate

Insulin + glucose

Tx underlying cause

27

Sx of hypercalcaemia

Stones = kidney stones
Bones = bone pain and fractures
Groans = constipation, anorexia, abdo pain, N+V
Moans = fatigue, myalgia, proximal muscle weakness, joint pain
Psychic Overtones= depression, memory loss, confusion, lethargy, coma

28

what are the commonest causes of hypercalcaemia

primary hyperparathyroidism
hypercalcaemia of malignancy

29

how can you differentiate between cancer and hyperparathyroid as a cause of hypercalcaemia

PTH is high in primary hyperparathyroidism

30

Tx of hypercalcaemia

IV saline
Biphosphonates e.g. pamidtronate

31

what happens in familial hypocalciuric hypercalcaemia

a high calcium level is sense by the parathyroids as normal i.e. have normal levels of PTH

32

how can hypocalciuric hypercalcaemia be differentiate from hyperparathyroidism

urinary calcium excretion is inappropriately low in FHH

33

what are features of adrenal insufficiency

lethargy
anorexia
pigmentation of hands/mouth
abdo pain
weight loss

34

what are features of adrenal insufficiency acute crisis

postural hypotension
vomiting
nausea
dehydration

35

what can cause adrenal insufficiency

TB
Autoimmune i.e. Addison's disease

36

what blood results are seen in Addison's disease

hyponatraemia
hyperkaelamia
elevated serum urea

37

Ix for Addison's

short ACTH stimulation test/Synacthen test;
- ACTH given, which should stimulate the release of cortisol
- in Addison's plasma cortisol remains low

38

what is not being made in hypo function of the adrenal cortex

cortisol
aldosterone

39

what test can be done to see if secondary failure of the adrenal cortex is due to pituitary insufficiency

insulin stress test

40

Tx of Addison's

15-25mg hydrocortisone (as cortisol replacement) daily in 2-3 doses.

Fludrocortisone as aldosterone replacement