hypernatremia objectives Flashcards
what is always associated with hypernatremia
hypertonicity
cellular dehydration
hypovolemic hypernatremia indicates what cause?
- renal water loss (diuretics, hyperglycemia, intrinsic renal disease)
- extrarenal water loss (vomiting, sweat, burns…)
hyopervolemic hypernatremia is caused by what
hypertonic fluid administration
mineralocorticoid excess
what is decreased TBW with near normal total body Na called?
what causes it?
Hypernatremia with euvolemia:
- extrarenal losses via respiratory and skin
- diabetes insipidus
- primary hydopipsia (reset osmostat)
what is increased Na with normal or increased TBW called? what causes it?
hypernatremia with hypervolemia
- hypertonic fluid administration
- mineralocorticoid excess
what types of hpertonic fluids can lead to hypernatremia with hypervolemia
3% saline
sodium bicarbonate
TPN’s
what can lead to mineralocorticoid excess leading to hypernatremia
- adrenal tumors secreting deoxycorticosterone
2. congenital adrenal hyperplasia
what causes congenital adrenal hyperplasia
11-hydroxylase defect
what type of extrarenal losses are related to hypernatremia with hypovolemia
- skin: burns and sweating
2. GI: vomiting and diarrhea
what type of renal losses are related to hypernatremia with hypovolemia
loop diuretics
osmotic diuresis: glucose, urea or mannitol
intrinsic renal disease
what type of extrarenal losses are related to hypernatremia with euvolemia
respiratory: tachypnea
skin: fever and sweat
how is rapidly developing hypernatremia treated?
correct serum sodium at a rate of 1 mEq/L/hour
-rapid correction won’t increase risk of cerebral edema
how is chronic hypernatremia treated
correct serum sodium at a rate of 0.5 mEq/L/Hr
-slow to prevent cerebral edema or convulsions
what is the recommended targeted fall in serum sodium for chronic hypernatremia?
what is goal serum sodium level
10 mEq/L/24 hours
145 mEq/L
what fluids are used for correcting serum sodium in hypernatremia
PO fluids preferred IV hypotonic fluids: D5 .2 NACl .45 NaCl
if a patient has hypovolemic hypernatremia what should be given
normal saline until circulatory status stabilizes, then switch to hypotonic fluid
how is isovolemic hypernatremia treated?
lots of water (usually just in folks with no access to water)
what is the most common cause of central diabetes insipidus
central DI= ADH is not released
what is the most common cause of nephrogenic diabetes insibidus
nephrogenic DI = ADH does not work on kidneys
what is the most common cause for secondary central diabetes insibidus
neoplasms
what causes nephrogenic diabetes insibidus
congenital
secondary nephrogenic DI= electrolyte disorder or drugs such as lithium
how is central diabetes insibidus treated?
central DI is treated with ADH replacement:
nasal desmopressin
chorpropamide PO (hypoglycemic releasing ADH)
clofibrate
carbamazepine
what drug will not work on nephrogenic or complete diabetes insipidus
chlorpropamide
how is nephrogenic diabetes insipidus treated?
treat underlying causes:
- electrolyte imbalance
- d/c drugs such as lithium or demeclocycline
- can use thiazide diuretics
- K sparing diuretics
- NSAIDS
what is commonly used to treat lithium induced diabetes insipidus
K sparing diuretics (such as amiloride)
what two drugs are most commonly used for nephrogenic induced DI
HCTZ and indomethacin
