hypernatremia objectives

Question 1

what is always associated with hypernatremia

Answer 1

hypertonicity

cellular dehydration

Question 2

hypovolemic hypernatremia indicates what cause?

Answer 2

1. renal water loss (diuretics, hyperglycemia, intrinsic renal disease)
2. extrarenal water loss (vomiting, sweat, burns…)

Question 3

hyopervolemic hypernatremia is caused by what

Answer 3

hypertonic fluid administration

mineralocorticoid excess

Question 4

what is decreased TBW with near normal total body Na called?

what causes it?

Answer 4

Hypernatremia with euvolemia:

1. extrarenal losses via respiratory and skin
2. diabetes insipidus
3. primary hydopipsia (reset osmostat)

Question 5

what is increased Na with normal or increased TBW called? what causes it?

Answer 5

hypernatremia with hypervolemia

1. hypertonic fluid administration
2. mineralocorticoid excess

Question 6

what types of hpertonic fluids can lead to hypernatremia with hypervolemia

Answer 6

3% saline
sodium bicarbonate
TPN’s

Question 7

what can lead to mineralocorticoid excess leading to hypernatremia

Answer 7

1. adrenal tumors secreting deoxycorticosterone

2. congenital adrenal hyperplasia

Question 8

what causes congenital adrenal hyperplasia

Answer 8

11-hydroxylase defect

Question 9

what type of extrarenal losses are related to hypernatremia with hypovolemia

Answer 9

1. skin: burns and sweating

2. GI: vomiting and diarrhea

Question 10

what type of renal losses are related to hypernatremia with hypovolemia

Answer 10

loop diuretics
osmotic diuresis: glucose, urea or mannitol
intrinsic renal disease

Question 11

what type of extrarenal losses are related to hypernatremia with euvolemia

Answer 11

respiratory: tachypnea
skin: fever and sweat

Question 12

how is rapidly developing hypernatremia treated?

Answer 12

correct serum sodium at a rate of 1 mEq/L/hour

-rapid correction won’t increase risk of cerebral edema

Question 13

how is chronic hypernatremia treated

Answer 13

correct serum sodium at a rate of 0.5 mEq/L/Hr

-slow to prevent cerebral edema or convulsions

Question 14

what is the recommended targeted fall in serum sodium for chronic hypernatremia?
what is goal serum sodium level

Answer 14

10 mEq/L/24 hours

145 mEq/L

Question 15

what fluids are used for correcting serum sodium in hypernatremia

Answer 15

PO fluids preferred
IV hypotonic fluids:
D5
.2 NACl
.45 NaCl

Question 16

if a patient has hypovolemic hypernatremia what should be given

Answer 16

normal saline until circulatory status stabilizes, then switch to hypotonic fluid

Question 17

how is isovolemic hypernatremia treated?

Answer 17

lots of water (usually just in folks with no access to water)

Question 18

what is the most common cause of central diabetes insipidus

Answer 18

central DI= ADH is not released

Question 19

what is the most common cause of nephrogenic diabetes insibidus

Answer 19

nephrogenic DI = ADH does not work on kidneys

Question 20

what is the most common cause for secondary central diabetes insibidus

Answer 20

neoplasms

Question 21

what causes nephrogenic diabetes insibidus

Answer 21

congenital

secondary nephrogenic DI= electrolyte disorder or drugs such as lithium

Question 22

how is central diabetes insibidus treated?

Answer 22

central DI is treated with ADH replacement:
nasal desmopressin
chorpropamide PO (hypoglycemic releasing ADH)
clofibrate
carbamazepine

Question 23

what drug will not work on nephrogenic or complete diabetes insipidus

Answer 23

chlorpropamide

Question 24

how is nephrogenic diabetes insipidus treated?

Answer 24

treat underlying causes:

1. electrolyte imbalance
2. d/c drugs such as lithium or demeclocycline
3. can use thiazide diuretics
4. K sparing diuretics
5. NSAIDS

Question 25

what is commonly used to treat lithium induced diabetes insipidus

Answer 25

K sparing diuretics (such as amiloride)

Question 26

what two drugs are most commonly used for nephrogenic induced DI

Answer 26

HCTZ and indomethacin