Question

A 35-year-old woman had surgery to remove a cerebral tumor. One month after the procedure, she reports being excessively thirsty and drinking several liters of water per day. She must also urinate so frequently that she avoids leaving the house. Laboratory tests indicate that her urine has a very low specific gravity. What is the most likely diagnosis of this woman's condition?

(A) Acute renal failure
(B) Glomerulonephritis
(C) Chronic renal failure
(D) Diabetes insipidus
(E) Urinary incontinence

Answer 1

The most likely diagnosis for the woman with excessive thirst and urination following brain surgery is Diabetes insipidus, due to a lack of antidiuretic hormone (ADH), leading to the production of dilute urine and increased thirst.

Step-by-step explanation:

The most likely diagnosis for the 35-year-old woman who has undergone surgery to remove a cerebral tumor and is now experiencing excessive thirst and urination with a very low specific gravity of urine is Diabetes insipidus (D). Diabetes insipidus is characterized by chronic underproduction of antidiuretic hormone (ADH) or a mutation in the ADH receptor.

This condition prevents the kidneys from retaining water, leading to the production of a high volume of very dilute urine and consequent excessive thirst. It is important to distinguish this condition from Diabetes mellitus, which involves high blood glucose levels and the presence of glucose in the urine.

Unlike Diabetes insipidus, Diabetes mellitus can lead to dehydration and persistent hunger because cells are unable to access glucose. The other conditions listed, such as acute renal failure, chronic renal failure, glomerulonephritis, and urinary incontinence, do not present with symptoms of low specific gravity urine and excessive thirst and urination as primary complaints.