Question 1

A high school athlete is brought to the emergency department after collapsing during outdoor practice on a hot day. The patient is weak, irritable, and confused. Serum sodium is 152 mEq/L and has dry mucous membranes and tachycardia. What is the initial approach to rehydration in this patient?

A) Hypotonic intravenous fluid replacement
B) Intravenous fluid resuscitation with an isotonic solution
C) Loop diuretics and hypotonic intravenous fluids
D) Oral water replacement

B

Accepted Answer

The initial approach to rehydration in this patient would be intravenous fluid resuscitation with an isotonic solution, such as normal saline. Hypotonic fluid replacement would lead to further dilution of the already elevated serum sodium levels, worsening the condition. Loop diuretics would be contraindicated as they would exacerbate the dehydration. Oral water replacement would not be enough in this acute setting and the patient's confused state may make it difficult to consume the necessary amount of fluids orally.

Question 2

A patient has euvolemic hyponatremia secondary to chronic syndrome of inappropriate antidiuretic hormone (SIADH) and is hospitalized for fluid replacement. When preparing to discharge the patient home, what will be included in teaching?

A) Limiting dietary protein intake
B) Limiting fluids to 500 mL/day for several days
C) Restriction of sodium intake
D) The importance of adherence to vaptan therapy

B

Accepted Answer

B

Question 3

An elderly patient who is taking a thiazide diuretic has been ill with nausea and vomiting and is brought to the emergency department for evaluation. An assessment reveals oliguria, hypotension, and tachycardia and serum sodium is 118 mEq/L. What is the treatment?

A) A single infusion of hypertonic saline
B) Addition of spironolactone
C) Emergency volume repletion with 3% NaCl.
D) Fluid and dietary sodium restriction

C

Accepted Answer

The patient is experiencing hyponatremia, likely as a result of the thiazide diuretic. The low serum sodium level is causing symptoms of hypotension, tachycardia, and oliguria. The most appropriate treatment in this acute setting is emergency volume repletion with hypertonic saline (3% NaCl) to increase serum sodium levels quickly and alleviate symptoms. A single infusion of hypertonic saline is preferable to avoid a rapid correction of serum sodium which can lead to osmotic demyelination syndrome. Addition of spironolactone or fluid and dietary sodium restriction would not provide the urgent correction needed in this situation.

Deck 190: Hypernatremia and Hyponatremia