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
