Paulson - Sodium Flashcards
hypernatremia parameter
over 145 mEq/L
mc cause of hypernatremia
water depletion
main extracellular cation
Na
pt population at high risk for hypernatremia
elderly → decreased thirst and access to fluids
3 classifications of fluid volume
hypervolemia
hypovolemia
euvolemia
3 causes of water loss
skin
GI
urine
3 clinical/pathologic causes of urine water/sodium loss
osmotic diuresis
diabetes insipidus
diuretics
2 causes of hypervolemic hypernatremia
iatrogenic from hypertonic saline or dialysis
hyperaldosteronism
2 causes of hypovolemic hypernatremia
renal losses → renal dz or diuretics
extrarenal losses
2 types of euvolemic hypernatremia
hypodipsia
diabetes indipidus
early s/sx of hypernatremia
anorexia
restlessness
n/v
more advanced sign of hypernatremia
AMS
order of AMS progression in hypernatremia
- lethargy/irritability
- stupor or coma
neurologic sx of hypernatremia (5)
twitching
hyperreflexia
ataxia
tremor
sz
sx of dehydration (7)
dry mm
tenting/poor skin turgor
lack of tears
decreased salivation
tachycardia
hypotn
oliguria/anuria
definition of chronic hypernatremia
present 2 or more days
chronic hypernatremia is less likely to present w.
neurologic sx
what pt pop does chronic hypernatremia make you think about
underlying neuro dz → impaired thirst → brain adaptation to hypernatremia
acute hypernatremia is more likely to present w.
neurologic sz
lab to order to diagnose hypernatremia
bmp → > 145
cause of hypernatremia is usually obvious from hx; if not, test to order
urine and plasma osmolality
hypernatremic + plasma osmolality > 295
extrarenal cause
hypernatremic + urine osmolality < plasma
diabetes insipidus
tx for hypernatremia
dilute fluids → correct/replace losses
for chronic hypernatremia, tx must be
slow!
what can happen if Na replacement is too quick for chronic hypernatremia
cerebral edema → sz → coma
fluid tx for chronic hypernatremia
D5W 1.35 mL/hr x wt in kg
Na should not be lowered > __
over __
10 mEq/L
24 hr
when should you recheck Na and glucose after initiation of fluids
4-6 hr after initiation
poor outcomes are associated w. hypernatremia and (3)
perioperative
PNA
VTE
definition of acute hypernatremia
less than 2 days
acute hypernatremia should be corrected w.in __
24 hr
fluid tx for acute hypernatremia
D5W 3-6 mL/kg/hr
OR
½ NS
what fluid should NOT be used for hypernatremia
NS
Na and glucose monitoring for acute hypernatremia
q 1-2 hr until Na < 145
after Na reaches < 145 in acute hypernatremia you should
decrease rate to 1 mL/kg/hr until goal of 140
steps in fluids for acute hypernatremia (3)
- D5W 3-6 mL/kg/hr OR ½ NS
- monitor Na and glucose q 1-2 hr until Na < 145
- decrease rate to 1 mL/kg/hr until goal of 140
goal for Na reduction for acute hypernatremia
1-2 mEq/L each hour
rate of correction for chronic hypernatremia
no more than 10 mEq/L/day
rate of correction for acute hypernatremia
lower to near normal in first 24 hr
hyponatremia definition
Na < 135 mEq/L
mc lyte d.o seen in hospitalized pt’s
hyponatremia
mc cause of hypervolemic hyponatremia
fluid overload
water is added or retained → amt of Na in serum is diluted
4 ex of pathologic hypervolemic hyponatremia
CHF
cirrhosis
IVF
nephrotic syndrome
cause of hypovolemic hyponatremia
both water and Na are lost → more Na than water
water and Na losses in hypovolemic hyponatremia can be either (2)
renal losses
extrarenal losses
renal losses of water and Na
diuretics → esp thiazides
extrarenal water and Na losses (4)
diarrhea
sweating
blood loss
fluid shifts
5 causes of euvolemic hyponatremia
adrenal insufficiency
polydipsia
hypothyroidism
syndrome of inappropriate antidiuretic hormone (SIADH)
reset osmostat
4 causes of SIADH
intracranial
paraneoplastic syndrome
pulmonary dz
meds
2 meds that cause SIADH
SSRI
cyclophosphamide
classification of hyponatremia by tonicity
hypotonic
isotonic
hypertonic
4 causes of hypotonic hyponatremia
SIADH
CHF, cirrhosis, diuretics → blood volume depletion
endocrine d.o
advanced renal failure
endocrine d.o that cause hypotonic hyponatremia (3)
hypothyroid
adrenal insufficiency
ex of isotonic hyponatremia
pseudohyponatremia
increased serum lipids or proteins cause erroneous measurement of Na levels
pseudohyponatremia
2 causes of hypertonic hyponatremia
significant hyperglycemia
mannitol, maltose sucrose retention
hyponatremia usually becomes symptomatic when Na is
125-130
possible sx of hyponatremia (6)
anorexia
n.v
lethargy
disorientation
ha
sz
possible clinical sx of hyponatremia (9)
weakness
agitation
hyporeflexia
orthostatic hypotn
delirium
coma
sz
resp arrest
brainstem herniation
1st diagnostic steps for hyponatremia
BMP + serum osmolality
which diagnostic test gives you info regarding tonicity cause of hyponatremia
serum osmolality
other helpful tests for hyponatremia
urine osmolality
lytes
TSH
plasma cortisol
ACTH stimulation
brain/lung imaging
hyponatremia flow chart
in euvolemic hyponatremia, urinary Na is usually
Na > 20 mEq/L
euvolemic hyponatremia plus urine osmolality >100 suggests
SIADH
hypothyroid
adrenal insufficiency
stress
drug use
euvolemic hyponatremia plus urine osmolality < 100 suggests
primary polydipsia → low Na intake
beer potomania syndrome
4 meds to know that cause hyponatremia
thazides
antipsychotics
SSRIs
contrast agents
classification of hyponatremia
acute
subacute
chronic
severe
moderate
mild
acute hyponatremia
w.in last 24 hr
subacute hyponatremia
w.in last 24-48 hr
chronic hyponatremia
w.in > 48 hr
severe hyponatremia
120 or lower
moderate hyponatremia
121-129
mild hyponatremia
130-135
pt w. any symptoms of hyponatremia needs
emergency therapy
even mild sx
emergency fluid for symptomatic hyponatremia
hypertonic saline
goal and monitoring for Na replacement for emergent tx (symptomatic pt)
raise NA by 4-6 over a couple hours
check Na q 2 hr
goal for non-emergency Na replacement
bring Na up slowly
overly rapid correction of hyponatremia can cause
osmotic demyelination syndrome (same-same central pontine myelinolysis)
tx for hypovolemic hyponatremia
isotonic saline
tx for hypervolemic hyponatremia: CHF, cirrhosis (3)
diuresis
fluid restriction
Na restriction
tx for hypervolemic hyponatremia: renal failure
fluid restriction
dialysis
Na restriction
tx for euvolemic hyponatremia
fluid restriction
if SIADH → +/- salt tabs and/or loop diuretic
what is demeclocycline used off label for
SIADH
indication for demeclocycline
SIADH pt who do not respond to salt tabs/loop diuretics
s.e of demeclocycline (3)
renal toxicity → esp cirrhosis pt
nephrogenic DI
intracranial htn
salt tabs should NEVER be given to
edematous pt