Exam 3 -electrolyte disorders- Darrow Flashcards
tonicity is calculated how
serum osmolality
how do you get hypotonic with hyponatremia
taking in water
in a hypotonic, hypovolemic patient, what is Urinary Na
less than 10 because trying to hold onto it
how does hypovolemia lead to increased Na reabsorption
decreased volume produces bator stretch with increased SAN to activate RAAS
decreased CO also will cause dec RBF and GFR which inc NA reabsorption
Why is serum Na so low in a dehydrated patient who is hypo everything
ADH overiding everything
retaining water which is diluting the Na
What is the exception of hyponatremia that is not attributed to increase in ADH
pyschogenic polydipsia
What is normal tonicity
280-295
what is low tonicity
<280
what is high tonicity
> 295
what can cause isotonic hyponatremia
artifactual pseudohyponatremia from extra fat and protein
hyperproteinemia (myeloma)
hyperlipidemia (chylomicrons, TG)
what can cause hypertonic hyponatremia
extra carbs hyperglycemia mannitol, sorbitol, glycerol maltose radiocontrast agents ethylene glycol methanol
what must you look into when have hypotonic hyponatremia
volume stat
What could cause a hypotonic, euvolemic hyponatremia
SIADH pyschogenic polydipsia hypothyroidism stress HIV
What is the Urinary Na excretion in hypotonic euvolemic hyponatremia
> 20
what are 2 groups of hypotonic hypovolemic hyponatremia and correlating Urinary Na
extra renal salt loss 20 Urinary Na
what are types of extra renal salt loss
dehydration, vomiting, diarrhea, 3rd spacing (burns)
what are types of renal salt loss
diuretics, ACEI, nephropathies, Addisons, type IV RTA
what can cause hypotonic hypervolemic hyponatremia
and Urinary Na?
edematous states: UNa20)
What are the effects of NSAIDs on ADH
increase because inhibit PG
what are the effects of increased serotonin on ADH
increase ADH
why do hyponatremic patients present with hypokalemic alkalosis
Na reabsorption in Collecting duct in exchange for one K and one H
what does hypokalemia look like on EKG
flattened to inverted T waves with U waves
what is contraction alkaosis
increase HCO3 because losing so much K and H
Why do you see hyperuremia (increased BUN) in hyponatremia
lost Na in tubule because reabsorbing so much so Urea flows down concentration gradient
What is a normal BUN/Cr
10:1
if BUN/Cr is >10:1 what does this mean
pre or post renal problem
What are causes of pre renal diseases that have elevated BUN/Cr
dehydraiont, CHF, shock, glomerulonephritis
what post renal diseases can lead to elevated BUN.Cr
prostatic obstruction
ureteral obstruction
what does BUN/Cr 10/1 mean
normal or intrinsic renal disease if Cr is >1
If BUN:Cr is less than 10:1 what could it be
liver failure, malnutrition, overhydration, pregnancy, SIADH
patient has pancreatitis with muddy brown granular casts
Dx?
ATN
epithelial casts are a marker for what
tubular necrosis
what exogenous toxins cause acute tubular necrosis
aminoglycosides
vancomycin
clyclosporin
radiographic contrast media
what endogenous toxins cause ATN
myoglobinuria
Hb
hyperuricemia
bence jones
what are locations of ADH release
brain and lung
prolonged PR interval and peaked T waves on EKG is indicative of what
hyperkalemia
What is alcohols impact on phosphate
decreases
What does myoglobin cause in tubules
acute tubular necrosis
What is biggest concern to correct hypophosphate in renal ATN from rhabdomyolysis
replace it slowly to avoid hypocalcemia
What is clinical presentation of classic crush injury rhabdomyolysis
massive release of phosphate, uric acid and potassium with decreased Ca from Ca PO4 precipitation in tissues
What ion do you NOT correct in classic crush injury rhabdomyolysis
Ca because with improvement it will be released from tissues
