Salt and Water Cases

Question 1

when can you see acute symptomatic hyponatremia?

Answer 1

• marathon runners
• water-drinking contests
• fraternity hazing
• raves (MDMA)
• primary polydipsia

Question 2

how does repletion of hypokalemia cause overcorrection of hyponatremia?

Answer 2

• K+ exchanges w/ Na+; moves from intracellular to extracellular space
• also K+ moving intracellularly draws water w/ it from extracellular space

Question 3

how to treat hyponatremia d/t glycine irrigation?

Answer 3

• hypertonic saline or

- HD (will correct hyponatremia and remove glycine)

Question 4

adverse effects of Li+

Answer 4

• thyroid dysfunction
• cardiac arrhythmias
• nephrogenic DI (occurs in 40% of pts)

Question 5

tx for nephrogenic DI 2/2 Li+

Answer 5

• d/c Li+
• amiloride (blocks Li+ entry into principal cell via ENaC)
• thiazide diuretics

Question 6

what can happen w/ Li+ if started on diuretics?

Answer 6

Li+ level may increase! need to monitor level and/or reduce Li+ dose