Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 13

Following overnight (6 p.m. to 8 a.m.) fluid deprivation, the urine-to-serum osmolarity ratio in a patient who is exhibiting polyuria and polydipsia is 1:1. The ratio remains the same when a second specimen is tested at 10 a.m. ADH is then administered subcutaneously to the patient, and the fluid deprivation is continued until 2 p.m., when another specimen is tested.

a. What disorder do these symptoms and initial laboratory results indicate?

b. If the urine-to-serum osmolarity ratio on the 2 p.m. specimen is 3:1, what is the underlying cause of the patient’s disorder?

c. If the urine-to-serum osmolarity ratio on the 2 p.m. specimen remains 1:1, what is the underlying cause of the patient’s disorder?

Step 1 of 3

a.

The laboratory results and symptoms of the patient indicate diabetes insipidus.

Diabetes insipidus:

• Condition characterized by increased thirst and large volume of dilute urine excretion along with decreased fluid intake is called diabetes insipidus

• These symptoms are found in given clinical situation