Regulation and disorders of salt and water Flashcards

1
Q

How is total body water (TBW) calculated for both men and women?

A

Men: TBW = .6 x wt
women: TBW = .5 x wt

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

How much of total body water is in the ECF?

A

1/3 of TBW

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

How much of total body water is in the ICF?

A

2/3 of TBW

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

How much of the ECFV is in the ISF?

A

3/4 of the ECFV

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

Total body Na+ (TBNa) is synonymous with what?

A

ECFV

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

What indicates a change in TBNa?

A

Clinical signs and symptoms give clues about TBNa

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

What is the formula for Serum Na?

A

Serum Na = TBNa/ TBW

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

T or F: Total body Na+ = Serum Na+

A

FALSE

Serum Na = TBNa/ TBW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is sodium balance regulated?

A

Only by Effective Circulating Volume (ECV)

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

How and where does Angiotensin II regulate sodium?

A

Increase Na reabsoprtion

  • proximal tubule!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How and where does Aldosterone regulate sodium?

A

Increases Na+ reabsorption

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

How and where does ADH regulate sodium?

A

Increases WATER reabsorption

  • distal tubule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Effects of ADH on urine osmolarity?

A

Increases U osmlarity (concentrates)

  • due to increased water reabsorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the effective circulating volume?

A
  • relates to the fullness and tension within the arterial compartment
  • usually correlates with total ECFV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

When does effective circ. volume not correlates with total ECFV?

A
  1. CHF
  2. Liver disease
  • ECF is decreased due to either dec CO (CHF) or arterial vasodilation (splanchnic vasodilation in liver failure)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What occurs if the effective circ. volume decreases?

A

Angiotensin II: increases
Thirst: Increases
ADH: Increases

=> Na+ retention (RAAs)
=> Water absorption (ADH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Clinical features of volume depletion?

A
  1. Reduction in blood pressure
  2. Poor skin turgor, absence of dependent edema
  3. Disproportionate increase in BUN relative to serum creatinine:prerenal azotemia and reduced urine output
  4. Reduced urine Na except in cases with renal losses of Na
  5. Mental obtundation and cool extremities.
18
Q

Effects of volume depletion due to extra renal losses (i.e. Diarrhea or burns) on urine with normal renal function?

A

Urine: highly concentrated ( inc. Osm) but low Na+

  • Because Water and Salt are being reabsorbed
19
Q

Effects of volume depletion due to renal losses (i.e. Diuretics) on urine with normal renal function?

A

Urine: Inappropriately diluted (dec Osm) and somtimes high Na+

20
Q

When does Volume expansion occur?

A

When salt and water intake exceeds renal and extrarenal losses

  • usually Na+ and water retention by kidney
21
Q

Clinical features of volume expansion?

A
  1. Edema
  2. Distended JVD
  3. Crackles, pleural effusion
  4. ascites
22
Q

When are ADH levels high?

A

Water deprivation

23
Q

When are ADH levels low?

A

After consuming Water

24
Q

How is water balance regulated?

A
  1. Plasma osmolarity (osmoreceptor)
  2. Volume status (baroreceptor - non-osmotic)
  • note diff between this ans Na+ balance: Na+ only regulated by volume status!
25
Q

disease caused by too much ECFV?

A

Hyponatremia (low Na concentration)

26
Q

Disease caused by too little ECFV?

A

Hpernatremia (High Na conc. )

27
Q

Normal serum Na+ level?

A

~135 -140 mEq/L

28
Q

The cause of hyponatremia depends on what?

A

Changes in ECFV

  • so can be:
    1. Hypovolemic (hyponatremia)
    2. Hypervolemic (hyponatremia)
    3. Euvolemic (hyponatremia)
  • *excess TBW relative to TBNa**
29
Q

Causes of Hypovolemic Hyponatremia?

A

(decreased ECFV and ECV)

  • Renal/extra renal Na losses
    1. Diarrhea
    2. Burns
    3. Pancreatitis
    4. Diuretic Rx
30
Q

Causes of Hypervolemic Hyponatremia? (two types)

A

(inc ECFV)
A. Decreased ECF
1. CHF
2. Liver disease

B. Increased ECF

  1. Acute Kidney injury
  2. Chronic Kidney disease
31
Q

Causes of Euvolemic Hyponatremia?

A

[no change in ECFV (clinical symptoms)]

  1. SIADH
  2. Glucocorticoid def.
  3. Hypothyroidism
  4. Drugs
  5. Primary polydipsa
  6. poor solute intake
32
Q

Name that natremia:

  • Sodium depletion with reduction in ECF volume and secondary water retention due to non-osmotic stimulation of vasopressin release
A

Hypovolemic Hyponatremia

  • TBNa: vv
  • TBW: v
33
Q

Name that natremia:

  • Water retention due to autonomous or altered regulation of vasopressin release(SIADH)
A

Euvolemic Hyponatremia

  • TBNa: No Change
  • TBW: ^^
34
Q

Name that natremia:

  • Retention of both sodium and water in which the latter is sufficient to lower the sodium concentration despite an increase in total body sodium
A

Hypervolemic Hyponatremia

  • TBNa: ^
  • TBW: ^^
35
Q

Clinical findings: Edema, Distended JVD, crackles, pulmonary effusion

TBNa?

A

TBNa = ECFV

  • Increased ^
36
Q

Clinical findings: Normal

TBNa?

A

TBNa = ECFV

  • No Change
37
Q

Clinical findings: Hypotension, reduced skin turgor, flat neck veins, no recent fluid intake, vomiting, diarrhea, severe burns

TBNa?

A

TBNa = ECFV

  • Decreased v
38
Q

How does osmolarity reflect ADH levels?

A
  1. High ADH = High Urine Osmolarity
    - Due to inc. water reabsorption
  2. Low ADH = Low Urine Osmolarity
    - due to dec. water reabsorption
  • **value of Urine Osm relative to Plasma Osm.
39
Q

Usual cause of hypernatremia?

A

Excess water loss

  • rather than by sodium gain
40
Q

Causes of Hypernatremia?

A
  1. Inability to sense thirst (Disease of brain)
  2. Inability to obtain water
  3. Absent or resistance to ADH (along with insufficient water intake)
  4. Diabetes Insipidus
41
Q

Hypernatremia w/ U osm

A

Diabetes Insipidus

- excessive urination leading to hypernatremia