Small Group: Water Handling

Question 1

How does glucose level affect sodium?

Answer 1

For every 100 mg/dL increase in glucose, sodium gets corrected by an addition of 1.6 mEq/L

Question 2

To calculate serum osmolarity in a hyperglycemic patient, use the _________ sodium.

Answer 2

uncorrected

Question 3

Cortisol inhibits _______.

Answer 3

ADH

Question 4

In those with SIADH (or any syndrome involving excess ADH), the formula for the maximum amount of water they can consume in a day is ___________.

Answer 4

600 mOsm (the typical metabolic product in a day) / urine osmolarity of maximal dilution

Question 5

What is the formula for volume replacement?

Answer 5

0.6 x body weight (kg) x ([current Na] / [desired Na] - 1)

Question 6

What is the best treatment for SIADH in an asymptomatic patient?

Answer 6

Water restriction. If they become symptomatic, then you can give hypertonic saline and a loop diuretic.