07-07-2008, 07:47 PM
A 76-year-old healthy woman is evaluated after a fall. She did not lose consciousness. For the past 2 months she has been taking hydrochlorothiazide, 25 mg/d, for systolic hypertension.
The physical examination is remarkable only for a blood pressure of 150/90 mm Hg seated and 145/85 mm Hg standing.
Laboratory Studies
Serum electrolytes
Sodium 124 meq/L
Potassium 3.5 meq/L
Chloride 89 meq/L
Bicarbonate 25 meq/L
Blood urea nitrogen 8 mg/dL
Plasma glucose 98 mg/dL
Serum uric acid 2.5 mg/dL
Serum creatinine 0.6 mg/dL
Total protein 7.4 g/dl
Urine Specific gravity 1.026
Hydrochlorothiazide therapy is discontinued, and follow-up in 1 week is scheduled. At that time repeat laboratory tests show: serum sodium 126 meq/L, potassium 3.8 meq/L, chloride 90 meq/L, bicarbonate 24 meq/L, creatinine 0.6 mg/dL, blood urea nitrogen 8 mg/dL, plasma glucose 98 mg/dL, and total cholesterol 204 mg/dL. The urine specific gravity is 1.025.
Which of the following is most likely responsible for the patient™s hyponatremia?
( A ) Diuretic-related sodium losses
( B ) Surreptitious water drinking
( C ) Pseudohyponatremia
( D ) Inappropriate renal water conservation
( E ) A very low sodium diet
The physical examination is remarkable only for a blood pressure of 150/90 mm Hg seated and 145/85 mm Hg standing.
Laboratory Studies
Serum electrolytes
Sodium 124 meq/L
Potassium 3.5 meq/L
Chloride 89 meq/L
Bicarbonate 25 meq/L
Blood urea nitrogen 8 mg/dL
Plasma glucose 98 mg/dL
Serum uric acid 2.5 mg/dL
Serum creatinine 0.6 mg/dL
Total protein 7.4 g/dl
Urine Specific gravity 1.026
Hydrochlorothiazide therapy is discontinued, and follow-up in 1 week is scheduled. At that time repeat laboratory tests show: serum sodium 126 meq/L, potassium 3.8 meq/L, chloride 90 meq/L, bicarbonate 24 meq/L, creatinine 0.6 mg/dL, blood urea nitrogen 8 mg/dL, plasma glucose 98 mg/dL, and total cholesterol 204 mg/dL. The urine specific gravity is 1.025.
Which of the following is most likely responsible for the patient™s hyponatremia?
( A ) Diuretic-related sodium losses
( B ) Surreptitious water drinking
( C ) Pseudohyponatremia
( D ) Inappropriate renal water conservation
( E ) A very low sodium diet