Volume and Water Disorders Flashcards
What effect does the RAAS have on the glomeruli?
constricts the efferent arteriole
serum sodium concentration DOES NOT tell you __________
what is the patient’s TOTAL BODY SODIUM.
what’s normal serum sodium?
135-145 mEq/L
What are the CNS symptoms of hyponatremia?
Mild - apathy, headache, lethargy
Moderate - agitation, ataxia, confusion, psychosis
Severe - stupor, coma, tentorial herniation, cheyne-stokes
DEATH
What are the GI symptoms of hyponatremia?
VAN
vomiting, anorexia, nausea
What are MSK signs of hyponatremia?
muscle cramps
dimished deep tendon reflexes
What are CNS signs and symptoms of hypernatremia?
mild - restlessness, lethargy, irritability
moderate - disorientation, confusion
severe - stupor, coma, seizures
DEATH
What are the non-CNS signs and symptoms of hypernatremia?
Respiratory - labored breathing
GI - intense thirst, nausea, vomiting
MSK - muscle twitching, spasticity, hyperreflexia
What’s normal daily water intake?
1-1.5L/day
What’s typical insensible daily water loss?
0.5 L/day
What makes the collecting duct permeable to water so that it can be reabsorbed?
ADH
The ascending limb of the loop of Henle is also known as the ____________segment of the nephron
diluting
because it is pulling Na+ and other electrolytes OUT of the tubular fluid and reabsorbing them
what senses the osmolality of your plasma?
osmoreceptors in the hypothalamus
will release/supress ADH at the anterior pituitary
what’s normal plasma osmolality?
280-290 mOsm/Kg H20
What is the disorder of urine concentration
diabetes insipidus
How do you treat hypovolemic hyponatremia?
volume restoration with isotonic saline
identify and correct cause of water and sodium loss
(cholera and gastroenteritis)
How do you treat hypervolemic hyponatremia?
water restriction
sodium restriction
loop diuretics
treatment of underlying condition
ADH (V2) receptor antagonist (vaptans)
How do you treat euvolemic hyponatremia?
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
What happens in the CNS in hyponatremia?
At first, K+, Na+ and osmolytes leave
later, H2O moves in
what should you suspect when you see hypernatremia in a patient who has access to water?
Diabetes insipidus
