Schoenwald - Electrolytes Flashcards
electrolytes (4)
Na
K
Cl
CO2
main regulator of water and Na
kidney
primary circulating (extracellular) cation
Na
fxn of Na
neuromuscular fxn
serum levels of Na are a balance btw (2)
dietary intake
renal excretion
major contributor to plasma osmolality
Na → indicator of free body water
osmolality is useful in evaluating (2)
hyponatremia
ADH related illnesses
osmolality decreases w. __
and increases w. __
overhydration
dehydration
what hormone regulates body water and osmolality
adh
adh is stimulated by (3)
increased osmolality
hypovolemia
thirst
where does adh act
collecting tubule → increases permeability → increases water reabsorption → more concentrated urine
serum osmolality is elevated in (5)
hypernatremia
hyperglycemia
ketosis
dehydration
diabetes insipidus
serum osmolality is decreased in (2)
overhydration
SIADH
common cause of SIADH
drugs
SIADH leads to __ water absorption
and __ sodium levels
increased
decreased
lose Na in urine
what syndrome is associated w. inadequate amt of adh
diabetes insipidus
sx of diabetes insipidus
increased thirst
large volume of dilute urine
hypernatremia
urine osmolality measures
dissolved particles in urine
t/f: urine osmolality is more specific than specific gravity
t!
urine osmolality evaluates
ability of kidney to concentrate urine
urine osmolality is increased in (2)
siadh
chf
urine osmolality is decreased in (2)
diabetes insipidus
excess fluid intake
2 types of hyponatremia
Na depletion
dilutional
Na depletion hyponatremia is caused by
free water loss
dilutional hyponatremia is caused by
water intake > water output → renal failure
hyponatremia is usually asymptomatic until it drops to
< 120 mEq/L
sx of hyponatremia (3)
lethargy
nausea
muscle cramps
cerebral edema
causes of hypernatremia (3)
stroke → impaired thirst mechanism
water loss w.o Na loss → burns/fever
dehydration
urine sodium can be measured by (2)
spot testing
24 hr urine
urine sodium helps evaluate
renal vs nonrenal hyponatremia
increased urine Na can indicate (5)
dehydration
diuretics
adrenocortical insufficiency
siadh
ckd
decreased Na can indicate (2)
chf
diarrhea
hyponatremia flow chart
classifications of volume status
hypovolemia
euvolemia
hypervolemia
hyponatremia w. normal osmolality is called
isotonic hyponatremia
isotonic hyponatremia is associated w.
hyperproteinuria
hyperlipidemia
hyponatremia w. low osmolality is called
hypotonic hyponatremia
hyponatremia w. elevated osmolality is called
hypertonic hyponatremia
hypertonic hyponatremia is associated w. (2)
hyperglycemia
radiocontrast agents
hypovolemic hyponatremia is associated w. (3)
dehydration
diarrhea
vomiting
euvolemic hyponatremia is associated w. (2)
siadh
postop hyponatremia
hypervolemic hyponatremia is associated w. (3)
edema → chf
advanced renal failure
liver ds
primary intracellular cation
K+
fxn of K+
cardiac muscle fxn
is K+ reabsorbed from kidneys
no!
it is excreted
why does K+ need to be given IV to pt’s who can not eat
it is not reabsorbed by kidneys
as __ is reabsorbed
__ is lost
Na reabsorbed → K+ is lost
sx of hypokalemia (3)
malaise
skeletal m weakness
arrythmias
ekg findings of hypokalemia
flattened or inverted t waves
causes of hypokalemia (6)
diet
diuretics
burns
glucose administration
licorice
hyperaldosteronism
causes of hyperkalemia (6)
renal failure
acidosis
diet
ACEI
acute or chronic renal failure
hemolysis
in metabolic acidosis, K+ is driven
out of the cell
sx of hyperkalemia (4)
arrythmias
cardiac arrest
numbness/tingling
weakness
ekg findings of hyperkalemia
peaked t waves
most abundant extracellular anion
chloride
chloride is regulated by __
and exchanged for __
proximal tubules
bicarb ions
Cl is indirectly regulated by (2)
Na
water
is Cl test alone helpful
no!
causes of increased Cl (2)
dehydration
metabolic acidosis
causes of decreased chloride (3)
overhydration
siadh
vomiting
what do lytes help us determine (2)
acute vs chronic renal failure
fluid therapies
mc cause of acute renal failure
nephrotoxins → meds
t/f arf is usually reversible
t!
sx of arf (3)
n/v
ams
edema
prerenal causes of arf (4)
hypovolemia
hypotn
chf
renal artery stenosis
renal causes of arf (2)
nephrotoxins
ai dz
postrenal cause of chf
obstruction
key parameter for renal fxn management
GFR
__ and
__ are easier to measure than GFR, but are less reliable
BUN
Cr
aki definition
acute increase in SCr 0.5 mg/dl or higher
OR
over 50% of baseline
classification for aki
rifle
rifle criteria: risk
SCr increased 1.5 x
OR
GFR > 25% decrease from baseline
rifle criteria: injury
SCr increased 2x
OR
GFR > 50% decrease from baseline
rifle criteria: failure
SCr > 3 x
OR
SCr > 4 x w. acute increase > 0.5
OR
GFR decrease > 75% from baseline
other labs in evaluation of aki (4)
urine Na
Fena (fractional excretion of Na)
urine osmolality
BUN:Cr ratio
urine Na: > 20
Fena: < 1%
urine osmolality: 500
BUN:Cr: 20:1
prerenal aki
urine Na: > 40
Fena: 1-2%
urine osm: 250-300
BUN:Cr: < 15:1
intrinsic aki
ckd gfr parameters
in arf, CrCl will be
decreased
in arf K+ will be
elevated → hyperkalemia
UA in arf will be positive for (2)
protein
blood
mild - mod decrease in gfr over time w.o presence of uremic sx
chronic renal failure
2 mc causes of ckd
htn
dm
sx of progressed ckd (3)
fatigue
malaise
vomiting
labs elevated in ckd (2)
BUN
Cr
__ and
__ are usually normal until advanced ckd
UA
lytes
primary buffer system of body
carbonic acid/bicarbonate system
CO2 is regulated by __
bicarb is regulated by __
lungs
kidneys
equation of ife
•HCO3¯+H+«—-»H2CO3«—-»CO2+H2O
increase in blood CO2
respiratory acidosis
decrease in blood CO2
respiratory alkalosis
increase in blood bicarb
metabolic alkalosis
decrease in blood bicarb
metabolic acidosis
what does anion gap tell you (2)
lyte balance
acid-base balance
what does mudpiles cat stand for
reasons for metabolic acidosis:
methanol
uremia
dka
paraldehyde
iron, isoniazid
lactic acidosis
ethanol, ethylene glycol
salicylate/asa
carbon monoxide
aminoglycosides
theophyline
