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Flashcards in Sodium Deck (76):
1

What is the total body water for males?

60%

2

What is the total body water for females?

50%

3

What is the ratio of water found in the intracellular fluid?

2/3

4

What is the ratio of water found in the extracellular fluid?

1/3

5

What dictates the ECF volume?

The net gain/loss of Na

6

Describe the ECF when fluid loss is isotonic?

If fluid/blood loss is isotonic- the osmolality of the fluid is unchanges
-no change in ICF volume

7

Describe the ECF when fluid loss is hypotonic?

If fluid/blood loss is hypotonic- increases plasma osmolarity
-shifts ICF to ECF

8

What conditions commonly cause hyponatremia?

-Hospitalized patients
-Low total Na
-Hypovolemic patients (dehydrated patients)
-Elevated BUN:Cr ratio

9

Characteristics of Renal Sodium Loss (2)

Associated with...
- High urinary Na excretion
- High urinary osmolality (concentration)

10

What commonly causes renal Na loss?

Diuretics

11

This renal sodium loss is less common and its also called salt wasting nephritis

Renal Tubular Disease

12

What is typically associated with low urine Na excretion?

-Diarrhea
-Fever
-Sweat/Exercise

13

Decreased Na intake is commonly seen in patients with...

-Extremely poor diets (anorexia/alcoholics)
-Hospital patients that are on hypotonic IV fluids for a long time

14

Patients with hyponatremia commonly present with...

-Hypovolumic
-Low Na urine excretion
-High urine osmolality (concentrated)
-High BUN

15

How do people classify hyponatremia?

-Volume Status
-Osmolality

16

What are some factors that you need to know before classifying a patient with hyponatremia?

-History
-Volume Status
-BUN/Creatinine
-Urine osmolality/electrolytes
-Plasma osmolality

17

What is another phrase for hyponatremia with high plasma osmolality

Hypertonic hyponatremia

18

If a patient has elevated ECF osmolality, where does the water shift?

From ICF to ECF

19

If the fluid shifts from inside the cell to outside the cell, what would this do to the Na concentration?

Dilute the Na concentration

20

What is the most common cause of hypertonic hyponatremia?

Hyperglycemia

21

Describe hyperglycemias effect on hyponatremia?

-Osmotic diuresis (increase in urine rate) causes renal Na and water loss
-can further raise plasma osmolality (conc.)

22

If a patient has hyponatremia due to hyperglycemia, how do you treat?

Treat the hyperglycemia first
-Don't give saline (causes the fluid to leave the ICF)

23

What is another name for hyponatremia with normal plasma osmolality?

Pseudohyponatremia

24

What causes Pseudohyponatremia?

-Hyperlipidemia
-Hyperproteinemia (multiple myeloma)

25

What % of plasma is water?

93%

26

What is the remained 7% of plasma made of?

-Proteins
-Lipids

27

How does hyperlipidemia and hyperproteinemia cause Pseudohyponatremia?

-The water content of a given volume of plasma is decreased
(the solids have pretty much displaced the water in the plasma)
-Causes plasma sodium to be falsely low

28

Is treatment required for Pseudohyponatremia?

Nopers

29

What is another name for hyponatremia with low plasma osmolality?

Hypotonic hyponatremia

30

Is the volume of the ECF in excess/deficient in hypotonic hyponatremia?

Excess (hypervolemic)

31

What are a patients urine Na levels if they have renal failure?

Urine Na is greater than 20 meq/L (the kidneys are failing so the volume levels stay high)

32

What are a patients urine Na levels if they have CHF or hepatic cirrhosis?

Urine Na is less than 20 meq/L (they have increased venous pressure and this results in edema state)

33

If a patient has edema, where is the edema fluid moving?

From plasma to the interstitial fluid

34

What does the lose of plasma fluid result in?

Increase in the secretion of ADH and aldosterone

35

What effect does ADH and aldosterone have?

Causes an increase in the total body water and that exceeds the rise in sodium

36

What are treatment options for patients with hypotonic hyponatremia with ECF volume excess?

-Judicious sodium (limit sodium to 1-3 grams/day)
-Fluid Restriction (1-1.5 liters/day)
- water intake must be less than urine output

37

What are some signs of hypotonic hyponatremia with decreased ECF volume?

-Signs of dehydration because total sodium is depleted disproportionally to water losses

38

What are 2 causes of hypotonic hyponatremia with decreased ECF volume?

-Renal Losses
-Extra Renal Losses

39

What are examples of renal losses?

-Diuretic Therapy
-Adrenal Insufficiency
-ACE inhibitors

40

What effect does diuretic therapy have?

Pulls of volume and Na

41

What effect does adrenal insufficiency have?

-Low aldosterone
-Inability to retain Na and water

42

What effect do ACE inhibitors have?

-Low Aldosterone
-Inability to retain salt and water

43

What are examples of extra renal losses?

-Vomiting
-Diarrhea
-Sweat

44

What are clinical signs of hypotonic hyponatremia with hypovolemia?

Usually notice the depletion of water before the hyponatremia

45

What is treatment for hypotonic hyponatremia with hypovolemia?

-Reexpansion of ECF
-Use isotonic saline and correct any underlying disorders

46

What causes hypotonic hyponatremia with normal ECF volume?

-Primary Polydipsia
-Syndrome of inappropriate anti-diuretic hormone

47

What patients express primary polydipsia?

Psych patients
-Due to excess water intake

48

Describe urine sodium and urine concentration in primary polydipsia

-Urine sodium is less than 20 meq/L
-Urine osmolality is less than 100 mOsm/kg

49

What is the treatment for primary polydipsia?

-Water restriction
-Monitor plasma Na levels
-Don't want to increase Na too quickly

50

This is the most common cause of hyponatremia and is the diagnosis of exclusion

Syndrome of inappropriate anti-diuretic hormone

51

What causes the fluid and electrolyte balance in SIADH?

-Inability to excrete dilute urine
-Water retention in the body
-Low Sodium levels
-Often caused by Small Cell Lung cancer which secretes excess ADH

52

What are characteristics of SIADH?

-Low Na and osmolarity
-Adequate urine sodium excretion with high urine osmolality
-No edema
-No evidence of dehydration

53

What diseases/disorders is SIADH commonly seen in?

-Lung disease
-Malignancies
-CNS abnormalities
-Cortisol deficiency

54

What are 2 clinical signs of hyponatremia?

-Observed sodium concentrations are less than 120 meq/L
-Rate of fall in Na is rapid

55

What are initial symptoms of hyponatremia?

-Headache
-Nausea
-Cramps
-Malaise
-Lethargy

56

What are progressive symptoms of hyponatremia?

-Delirium
-Psychosis
-Seizures
-Coma

57

When is treatment of hyponatremia urgent?

-If Na is less than 110 meq/L or the patient is symptomatic

58

Asymptomatic patients should not exceed over _____ per hour

.5 meq/L per hour

59

Severe patients should not exceed over ______ per hour

1-1.5 meq/L per hour

60

Patients should never exceed _____ per day

12 meq/L per day

61

What is the major cause of hypernatremia?

Lack of free water access

62

What patients commonly present with hypoernatremia?

-Babies
-Psych patients
-Elderly patients
-Patients that have neurological problems that don't have thirst signals

63

The loss of volume leads to _______ BUN:Cr levels?

Elevated (because the kidneys aren't getting perfused and they cant filter)

64

The loss of volume leads to ______ urine osmolality?

High (because it is more concentrated)

65

_______ is the best indicator for following volume status

BUN:Cr

66

What are the 2 types of Diabetes Insipitus?

-Central DI
-Nephrogenic DI

67

Describe ADH in central DI

-ADH is absent

68

Do your thirst signals remain in central DI?

Yes they do man

69

What are 2 S and S for central DI?

-Polydipsia
-Polyuria

70

Central DI is associated with...

-Encephalopathy
-Head trauma
-Pituitary surgery
-Tumor

71

What is the treatment for Central DI?

-dDAVP (artificial ADH)
-Stimulates water and Na uptake

72

How do you confirm Central DI diagnosis?

-If the patient can concentrate the urine after receiving dDAVP

73

Describe ADH in nephrogenic DI?

-Kidneys are resistant to ADH (so they don't retain Na and water)

74

What are characteristics/ S&S for nephrogenic DI?

-Patients excrete large volumes of really dilute urine
-Low Na in urine
-Patients still have thirst signals
-If they are unable to get water they will become dehydrated quickly

75

What people tend to present with nephrogenic DI?

-3rd trimester pregnant patients

76

How do you diagnose Nephrogenic DI?

-Trial of water deprivation (if the patients fail to concentrate their urine they have nephrogenic DI)
-Lack of response to dDAVP