12-01-2010, 08:55 PM
A 57-year-old man is admitted to the hospital for
dehydration and confusion. In the emergency department
he complained of excessive thirst and he was found
to have a serum sodium of 162 meq/L and a newly elevated
creatinine of 2.2 mg/dL. After receiving IV fluid, his
sensorium clears and the patient relays to you that he
drinks large amounts of fluid each day and makes about 2
L of urine each day. He has noticed that his urine output
has no relation to the amount of fluid he drinks. His sodium
remains elevated at 150 meq/L, and his urine osmolality
returns at 80 mosmol/kg. After careful water
restriction, you administer 10 μg of desmopressin intranasally
and remeasure his urine osmolality. The osmolality
is now 94 mosmol/kg. What is the most likely cause of
his hypernatremia?
A. Chronic hyperventilation
B. Diabetes insipidus
C. Excessive solute intake
D. Gastrointestinal losses
E. Surreptitious use of diuretics
dehydration and confusion. In the emergency department
he complained of excessive thirst and he was found
to have a serum sodium of 162 meq/L and a newly elevated
creatinine of 2.2 mg/dL. After receiving IV fluid, his
sensorium clears and the patient relays to you that he
drinks large amounts of fluid each day and makes about 2
L of urine each day. He has noticed that his urine output
has no relation to the amount of fluid he drinks. His sodium
remains elevated at 150 meq/L, and his urine osmolality
returns at 80 mosmol/kg. After careful water
restriction, you administer 10 μg of desmopressin intranasally
and remeasure his urine osmolality. The osmolality
is now 94 mosmol/kg. What is the most likely cause of
his hypernatremia?
A. Chronic hyperventilation
B. Diabetes insipidus
C. Excessive solute intake
D. Gastrointestinal losses
E. Surreptitious use of diuretics