Hyponatremia and Electrolyte Disorders CIS

Question 1

serum osmolarity

Answer 1

2xNa + BUN/2.8 + glucose/18

Question 2

dehydrated low sodium

Answer 2

because of ADH secretion - water retention

Question 3

hyponatremia

Answer 3

most cases involved excess of ADH

Question 4

normal serum osmolarity

Answer 4

280-295

Question 5

isotonic hyponatremia

Answer 5

hyperprotein

hyperlipid

Question 6

hypertonic hyponatremia

Answer 6

hyperglycemia
mannitol, maltose
contrast dye
ethylene glycol

Question 7

hypotonic hyponatremia

Answer 7

look at volume status

Question 8

hypervolemic hypotonic hyponatremia

Answer 8

UNa < 10

edema
-CHF, liver disease, nephrotic, advanced kidney disease

Question 9

euvolemic hypotonic hyponatremia

Answer 9

UNa >20

SIADH

Question 10

hypovolemic hypotonic hyponatremia

Answer 10

extrarenal or renal
-look at NUa

UNa 20 renal

Question 11

hypovolemic hypotonic hyponatremic with UNa <10

Answer 11

extrarenal salt loss

-dehydration, vomiting, diarrhea, burns

Question 12

hypovolemic hypotonic hyponatremia with UNa >20

Answer 12

renal salt loss

• diuretics
• ACE (-)
• addisons
• cerebral sodium wasting
• obstruction
• type IV RTA

Question 13

hyponatremia definition

Answer 13

Na < 135

Question 14

for every 2 Na you absorb

Answer 14

dump 1K and 1H

-makes it hypokalemia and alkalotic

Question 15

tests for low K

Answer 15

EKG

-flat, inverted T waves and U waves

Question 16

increased BUN

Answer 16

elevated reabsorption with increased ADH (creates gradient for water)
-also - prox tub higher BUN gradient if volume low

Question 17

elevated BUN/Cr

Answer 17

high protein
pre-renal disease
post-renal disease

Question 18

low BUN/Cr

Answer 18

<10/1

liver failure, malnutrition, overhydration, preganancy, SIADH

Question 19

BUN/Cr of 10:1

Answer 19

normal renal function (Cr1)

Question 20

muddy brown casts

Answer 20

acute tubular necrosis

Question 21

causes of ATN

Answer 21

ischemia

toxins

Question 22

EKG hyperkalemia

Answer 22

prolonged PR interval and peaked T waves

Question 23

crush injury rhabdomyolysis

Answer 23

massive release of phosphate, uric acid, and K

Question 24

slow phosphate replacement

Answer 24

to avoid hypocalcemia

Question 25

pigmented granular casts and renal tubular epithelial cells

Answer 25

ATN

Question 26

ischemic ATN

Answer 26

shock

hypoP

Question 27

toxic ATN

Answer 27

myoglobin

Question 28

renal tubular cell regeneration

Answer 28

cuboidal first

• little water resorption
• lots of dilute urine

eventually - differentiates to brush border
-normal urine restored