Volume and Water Disorders

Question 1

What effect does the RAAS have on the glomeruli?

Answer 1

constricts the efferent arteriole

Question 2

serum sodium concentration DOES NOT tell you __________

Answer 2

what is the patient’s TOTAL BODY SODIUM.

Question 3

what’s normal serum sodium?

Answer 3

135-145 mEq/L

Question 4

What are the CNS symptoms of hyponatremia?

Answer 4

Mild - apathy, headache, lethargy

Moderate - agitation, ataxia, confusion, psychosis

Severe - stupor, coma, tentorial herniation, cheyne-stokes

DEATH

Question 5

What are the GI symptoms of hyponatremia?

Answer 5

VAN

vomiting, anorexia, nausea

Question 6

What are MSK signs of hyponatremia?

Answer 6

muscle cramps

dimished deep tendon reflexes

Question 7

What are CNS signs and symptoms of hypernatremia?

Answer 7

mild - restlessness, lethargy, irritability

moderate - disorientation, confusion

severe - stupor, coma, seizures

DEATH

Question 8

What are the non-CNS signs and symptoms of hypernatremia?

Answer 8

Respiratory - labored breathing

GI - intense thirst, nausea, vomiting

MSK - muscle twitching, spasticity, hyperreflexia

Question 9

What’s normal daily water intake?

Answer 9

1-1.5L/day

Question 10

What’s typical insensible daily water loss?

Answer 10

0.5 L/day

Question 11

What makes the collecting duct permeable to water so that it can be reabsorbed?

Answer 11

ADH

Question 12

The ascending limb of the loop of Henle is also known as the ____________segment of the nephron

Answer 12

diluting

because it is pulling Na+ and other electrolytes OUT of the tubular fluid and reabsorbing them

Question 13

what senses the osmolality of your plasma?

Answer 13

osmoreceptors in the hypothalamus

will release/supress ADH at the anterior pituitary

Question 14

what’s normal plasma osmolality?

Answer 14

280-290 mOsm/Kg H20

Question 15

What is the disorder of urine concentration

Answer 15

diabetes insipidus

Question 16

How do you treat hypovolemic hyponatremia?

Answer 16

volume restoration with isotonic saline

identify and correct cause of water and sodium loss

(cholera and gastroenteritis)

Question 17

How do you treat hypervolemic hyponatremia?

Answer 17

water restriction

sodium restriction

loop diuretics

treatment of underlying condition

ADH (V2) receptor antagonist (vaptans)

Question 18

How do you treat euvolemic hyponatremia?

Answer 18

Is it SIADH? - Is the plasma level of ADH inappropriately elevated relative to plasma osmolality (in other words, low osmolality and salty pee?)

acute (less than 48 hours)

increase serum sodium at rate up to 2 meq/hour until asymptomatic

chronic (greater than 48 hours)

rate of correction should not exceed 1 meq/hour (no more than 18 in 24 hours)

measure serum and urine electrolytes every 2 hours

perform frequent neuro evals

Question 19

What happens in the CNS in hyponatremia?

Answer 19

At first, K+, Na+ and osmolytes leave

later, H2O moves in

Question 20

what should you suspect when you see hypernatremia in a patient who has access to water?

Answer 20

Diabetes insipidus