Hyponatremia and Electrolyte Disorders CIS Flashcards
serum osmolarity
2xNa + BUN/2.8 + glucose/18
dehydrated low sodium
because of ADH secretion - water retention
hyponatremia
most cases involved excess of ADH
normal serum osmolarity
280-295
isotonic hyponatremia
hyperprotein
hyperlipid
hypertonic hyponatremia
hyperglycemia
mannitol, maltose
contrast dye
ethylene glycol
hypotonic hyponatremia
look at volume status
hypervolemic hypotonic hyponatremia
UNa < 10
edema
-CHF, liver disease, nephrotic, advanced kidney disease
euvolemic hypotonic hyponatremia
UNa >20
SIADH
hypovolemic hypotonic hyponatremia
extrarenal or renal
-look at NUa
UNa 20 renal
hypovolemic hypotonic hyponatremic with UNa <10
extrarenal salt loss
-dehydration, vomiting, diarrhea, burns
hypovolemic hypotonic hyponatremia with UNa >20
renal salt loss
- diuretics
- ACE (-)
- addisons
- cerebral sodium wasting
- obstruction
- type IV RTA
hyponatremia definition
Na < 135
for every 2 Na you absorb
dump 1K and 1H
-makes it hypokalemia and alkalotic
tests for low K
EKG
-flat, inverted T waves and U waves
increased BUN
elevated reabsorption with increased ADH (creates gradient for water)
-also - prox tub higher BUN gradient if volume low
elevated BUN/Cr
high protein
pre-renal disease
post-renal disease
low BUN/Cr
<10/1
liver failure, malnutrition, overhydration, preganancy, SIADH
BUN/Cr of 10:1
normal renal function (Cr1)
muddy brown casts
acute tubular necrosis
causes of ATN
ischemia
toxins
EKG hyperkalemia
prolonged PR interval and peaked T waves
crush injury rhabdomyolysis
massive release of phosphate, uric acid, and K
slow phosphate replacement
to avoid hypocalcemia
pigmented granular casts and renal tubular epithelial cells
ATN
ischemic ATN
shock
hypoP
toxic ATN
myoglobin
renal tubular cell regeneration
cuboidal first
- little water resorption
- lots of dilute urine
eventually - differentiates to brush border
-normal urine restored
