Hyponatremia and Electrolyte disorders Flashcards
Why would you have hyponatremia with dehydration?
Replacing blood volume > replacing sodium
ADH > aldosterone
Isotonic hyponatremia
Extra protein: myeloma
Extra fat: hyperlipidemia
Hypertonic hyponatremia
Extra carb:
1) hyperglycemia
2) mannitol, other sugars
3) radiocontrast
4) ethylene glycol, methanol
Hypotonic hyponatremia
Look at volume status
Hypovolemia
UNa 20 = renal salt loss
Euvolemia
UNa > 20 SIADH Cortisol Drug interactions (NSAIDs, SSRIs) Polydipsia
Hypervolemia
UNa 20 = Advanced kidney disease
Increased salt retention
Hypokalemia and alkalosis
Bicarb high - secondary aldosteronism, contraction alkalosis
Hypokalemia on EKG
Inverted T and U waves
BUN and dehydration
Elevated
Moves down conc gradient in to blood, ADH increase reabsorption
Elevated BUN/Creatinine ratio
High protein intake or breakdown: Catabolic state Catabolic drugs, ie tetracycline, steroids GI bleed Pre renal disease: Dehydration CHF Shock Glomerulonephritis Post renal disease: Prostatic obstruction Ureteral obstruction
Ratio of 10
Normal or intrarenal
Ratio less than 10
Low BUN
liver failure, malnutrition, overhydration, pregnancy, SIADH
Intrinsic renal failure with an anion gap acidosis
Decreased organic acid excretion
Increase UNa - no reabsorption
Decrease bicarb - no reabsorption
Ratio decreased - intrarenal failure
Hypotonic hypervolemia
No effective plasma volume
Low UNa - RAS