1: Sodium and water balance Flashcards Preview

Endocrine Week 4 2017/18 > 1: Sodium and water balance > Flashcards

Flashcards in 1: Sodium and water balance Deck (29)
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1

How is [Na+] calculated?

[Na+] = mmol NaL H2O

2

What is the reference range of [Na+]?

135 - 145 mmol/L

3

What level of Naindicates hyponatraemia?

< 120 mmol/L

4

What are the two possible mechanisms of hyponatraemia?

Decrease in [Na+]

OR

Increase in [H2O]

5

___ follows sodium everywhere it goes.

Water

6

What are the symptoms of hyponatraemia caused by a decrease in sodium concentration?

"Dry" symptoms:

Tachycardia

Postural hypotension

Dry mucuous membranes

Reduced urine output

Decreased level of consciousness

7

What is the main symptom of hyponatraemia due to increase in water concentration?

Increase in ECF and ICF volume, producing peripheral oedema

8

The volume of the ECF is ___ the volume of the ICF.

half

9

The volume of the ICF is ___ the volume of the ECF.

double

10

In terms of the ICF and ECF, where is

a) water

b) sodium found?

a) Water is found in both ECF and ICF

b) Sodium is only found in ECF (by action of sodium-potassium pump)

11

How are the two types of hyponatraemia treated?

Too much water ⇒ Fluid restrict

Too little sodium ⇒ Give sodium

12

How is sodium homeostasis maintained?

Mineralocorticoids (aldosterone)

13

Which gland produces mineralocorticoids like aldosterone?

Zona glomerulosa of the adrenal cortex

14

How do mineralocorticoids maintain sodium homeostasis?

Cause sodium reabsorption in the distal convoluted tubules of the kidneys

15

Which mineralocorticoid causes sodium retention in response to hypotension?

Aldosterone

RAAS

16

What happens when mineralocorticoids are produced in excess?

Sodium retention > Water retention > Hypernatraemia/volaemia

17

What happens when mineralocorticoids are deficient?

Sodium loss > Water loss > Hyponatraemia/volaemia

18

How is water homeostasis maintained?

ADH

19

Which gland secretes ADH?

Posterior pituitary

20

How does ADH maintain water homeostasis?

Promotes water reabsorption in the collecting ducts of the kidneys

21

What is the concentration of urine also known as?

Urine osmolality

22

ADH excess produces ___ urine and therefore a (high/low) urine osmolality.

ADH excess

concentrated urine

high urine osmolality

23

ADH deficiency produces ___ urine and therefore a (high / low) urine osmolality.

ADH deficiency

dilute urine

low urine osmolality

24

What condition causes ADH excessexcess water reabsorption and hyponatraemia?

SIADH

25

What level of Na+ indicates hypernatraemia?

> 160 mmol/L

26

What can cause an increase in sodium levels leading to hypernatreamia?

Conn's syndrome

IV drugs

Near-drowning

27

What can cause water loss leading to hypernatraemia?

Diabetes insipidus

Profuse vomiting (e.g DKA)

Inadequate H2O intake

28

How is water loss hypernatreamia treated?

Give water

29

How is hypernatraemia caused by sodium excess treated?

Loop diuretics

(To cause natriuresis)