Sodium and Water Balance Flashcards Preview

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Flashcards in Sodium and Water Balance Deck (21):
1

In the cell does water folow sodium or does sodium follow water?

Water follows sodium
Na+ loss means H2O loss

2

What controls the level of sodium?

Mineralocorticoid activity (sodium retention in exchange for K+ and/or H+ ions)

3

Which steroids have mineralocorticoid activity?

Aldosterone and cortisol

4

If you had too much mineralocorticoid activity what would happen?

Na+ retention

5

What controls the level of water?

Anti-diuretic hormone

6

Where from and when is ADH released?

From the posterior pituitary in response to osmotic (in health) and non-osmotic (in disease) stimuli

7

If there is increased levels of ADH, will the urine by dilute or concentrated?

Concentrated

8

How is the concentration of urine assessed?

As urine osmolality
Conc urine -- high urine osmolality
dilute urine -- low urine osmolality

9

What method occurs in the kidneys that leads to the fluid in the descending limb becoming more hypertonic?

Countercurrent multiplication

10

What 2 methods can cause a patient to have decreased Na+ and how would you treat each one?

too much water - fluid restrict
too little sodium - give sodium

11

What 2 methods can cause a patient to have increased Na+ and how would you treat each one?

too much sodium - diuretics and then replace water only
too little water - give water

12

What can cause a patient to have too much water?

SIADH
copulsive water drinking
patient is not dry

13

Give causes of a patient having too little sodium.

increased Na+ loss (Addisons)
decreased Na+ intake (rare)
pateint is clinically dry

14

What could cause a patinet to have too little water?

Increaased water loss (DI)
Decreased water intake

15

What can cause a patient to have too much sodium?

rare
some IV meds
near drowing in sea
infants given hig salt feeds

16

What is the normal value range for sodium?

135- 145

17

Give examples of non-osmotic stimuli that trigger the release of ADH.

Hypovolaemia/ hypotension
Pain
Nausea/ vomiting

18

Do the non-osmotic stimuli override the osmotic stimuli?

Yes - ADH continues to be released so blood becomes very dilute

19

What happens when hypovolaemia occurs in hyponatraemia?

Even bigger Na+ deficit - too little sodium

20

How is Na/H2O balance assessed?

In the context of hyponatraemia or hypernatraemia

21

What symptoms can occur if the patients Na+ is very low (155mmol/l)?

May develop: altered consciousness, confusion, nausea