Disorders of Water Balance Flashcards

1
Q

a hypertonic environment has what effect on ADH levels

A
  • increases ADH levels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what does ADH release cause

A
  • increased tubular reabsorption of water
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

after the body fluid has been diluted and is now isotonic, what happens to ADH release and thirst reflex

A
  • inhibition of ADH release

- inhibition of thirst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

maximally dilute urine has what osmolality

A
  • 50-100
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

maximally dilute urine occurs under what conditions

A
  • large water intake

- no ADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

maximally concentrated urine has what osmolality

A
  • 1200
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

maximally concentrated urine under what condition

A
  • low water intake

- high ADH levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

osmoreceptors respond to what signal

A
  • high plasma osmolality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

sensitivity of osmoreceptors

A
  • highly sensitive

- respond to 1-2% change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

low pressure baroreceptors respond to what signal

A
  • decreased extracellular fluid volume
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

sensitivity of low pressure baroreceptors

A
  • lowly sensitive

- respond to 5% change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

high pressure baroreceptors respond to what signal

A
  • decreased blood pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

sensitivity of high pressure baroreceptors

A
  • low sensitive

- respond to 5% change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

direct neural receptors respond to what signals

A
  • drugs
  • vomiting
  • stress
  • ADH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

between osmoreceptors, low pressure and high pressure baroreceptors, and direct neural receptors, which are physiologic responses

A
  • osmoreceptors

- low pressure and high pressure baroreceptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

between pressure/volume and osmolality, which will cause greater release of ADH

A
  • pressure/volume trumps osmolality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

ICF is estimated by calculating

A
  • effective osmolality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

ICF is proportional to

A
  • 1/effective osmolality
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

sodium concentration is equal to

A
  • H2O balance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

ECF is estimated by

A
  • physical examination
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what parts of the physical exam would lead you to think increased ECF

A
  • edema
  • crackles
  • elevated JVP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what parts of the physical exam would lead you to think decreased ECF

A
  • low BP
  • increased pulse
  • decreased capillary refill
  • no edema
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

ECF volume =

A

Na+ balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

exceptions when total body sodium would not correlate with the clinical assessment of ECF volume

A
  • SIADH

- pure water loss

25
Q

what happens in SIADH

A
  • increased ECF
  • decreased total body Na

reabsorbing lots of free water and increasing ECF volume

26
Q

clinical shorthand for serum electrolytes

A

Na I Cl I BUN /
I I / Glucose
K I HCO3 I Creat \

27
Q

definition of hyponatremia

A
  • sodium concentration < 135 mEq/L
28
Q

how to calculate sodium concentration

A

ECF Na+ content

ECF H2O content

29
Q

If you have hypotonic hyponatremia and the urine Osm < 100 and the urine Na levels are < 20, what is the problem?

why would you have urine Osm < 100 and the urine Na levels are < 20

A
  • primary polydipsia - drinking too much water
  • low solute intake - not eating enough salt
  • ADH is not absorbing any additional water or concentrate the urine
30
Q

If you have hypotonic hyponatremia and the urine Osm > 100 and you are hypovolemic, what is your urine sodium concentration

A
  • less than 20
31
Q

If you have hypotonic hyponatremia and the urine Osm > 100 and you are hypovolemic and your urine Na concentration is less than 20, what is the cause

A
  • true hypovolemia
  • vomiting, diarrhea, burns

you are losing lots of water so your RAAS system is activated. You are reabsorbed sodium through aldosterone so your urine concentration of Na is low.

32
Q

If you have hypotonic hyponatremia and the urine Osm > 100 and you are hypervolemic, what is your urine sodium concentration

A

less than 20

33
Q

If you have hypotonic hyponatremia and the urine Osm > 100 and you are hypervolemic and your urine Na concentration is less than 20, what is the cause

A
  • CHF
  • Cirrhosis
  • Nephrosis

your RAAS system is activated due to decreased perfusion to the heart and so you have aldosterone reabsorbed Na but you are hypervolemic because of edema and leakage elsewhere

34
Q

If you have hypotonic hyponatremia and the urine Osm > 100 and you are euvolemic, what is your sodium concentration in your urine

A

> 40

35
Q

If you have hypotonic hyponatremia and the urine Osm > 100 and you are euvolemic and your urine Na concentration is greater than 40 what is the cause

A
  • SIADH

your ADH is overproduced and you are reabsorbing lots of water but not solutes. with euvolemia, RAAS is not activated so you won’t reabsorb Na.

36
Q

some causes of SIADH

A
  • vigorous exercise
  • tumors
  • NSAIDS
  • SSRIs
  • Ecstacy
37
Q

diagnosis of pseudohyponatremia

A
  • normal serum sodium
  • increased osmolal gap
  • asymptomatic
  • normal ECF volume
  • increased lipoproteins or protein
38
Q

when might you have increased lipoproteins or proteins

A
  • myeloma
39
Q

how to calculate osmolal gap

A
  • measured Osm - calculated Osm
40
Q

normal osmolal gap

A

< 10 mOsm/Kg

41
Q

causes of hypertonic hyponatremia

A
  • hyperglycemia
  • mannitol
  • glycine
  • sorbitol
  • sucrose
42
Q

when does acute hyponatremia occur (time frame)

A
  • 1-2 days
43
Q

when does chronic hyponatremia occur (time frame)

A
  • after 3 days
44
Q

how do we treat symptomatic hyponatremia

A
  • 3% saline
45
Q

treatment of hypotonic hyponatremia when patient is hypovolemic

A
  • give fluids

- isotonic saline

46
Q

treatment of hypotonic hyponatremia when patient is euvolemic

A
  • fluid restriction
  • salt tablets
  • loop diuretics
  • V2 antagonist
  • 3% saline
  • demeclocycline
47
Q

treatment of hypotonic hyponatremia when patient is hypervolemia

A
  • Na+ fluid restriction

- diuretics

48
Q

safe goal for rapid correction of hyponatremia

A
  • 4-6 mEq/L in 24 hours
49
Q

side effects of rapid correction of hyponatremia

A
  • osmotic demyelination syndrome
  • OR central pontine myelinolysis
  • axonal demyelination
  • rapid increase in sodium
50
Q

hypernatremia definition

A
  • concentration of Na > 145 mEq/L
51
Q

what is diabetes insipidus

A
  • ADH not working
52
Q

what is primary polydispia

A
  • just drinking a lot of water
53
Q

if you are doing a water deprivation test and you have a high urine osmolarity, what is the most likely cause

A
  • patient is just drinking too much water
54
Q

if you are doing a water deprivation test and you have a low urine osmolality, what is the most likely cause

what do you do next

A
  • something isn’t absorbing the water and concentrating urine
  • do a desmopressin test
55
Q

if you are doing a water deprivation test and you have a low urine osmolality and patient responds to desmopressin by increasing concentration of urine, what is the cause

A
  • central diabetes insipidus

- gestational diabetes insipidus

56
Q

if you are doing a water deprivation test and you have a low urine osmolality and patient does not respond to desmopressin and urine concentration remains low what is the cause

A
  • nephrogenic diabetes insipidus
57
Q

what is diuresis

A
  • excessive production of urine
58
Q

what is a negative effect of rapid treatment of hypernatremia

A
  • cerebral edema