Question

Following a motor accident, a patient complained of headaches, being constantly
thirsty and urinating more frequently than usual. A computed tomography (CT) scan
showed that the patient had which one of the following?
A. internal bleeding that damaged the posterior hypothalamus
B. a lesion (damage) to the anterior pituitary
C. a transection/disruption of the infundibulum
D. a blood clot in the hypothalamic-hypophyseal portal system

Answer 1

The posterior hypothalamus helps in thermoregulation. It also increase BP and dilates the pupil. So it does not have any part in increased thirst and urination. So option A is not correct answer.
Anterior pituitary secretes LH, FSH, growth hormone, ACTH and thyroid stimulating hormone. None of these hormones take part in increased thirst and urination. So option B is not the correct answer.

Infundibulum or the pituitary stalk contains connection between the hypothalamus and posterior pituitary known as hypothalamus hypophyseal tract. Damage to infundibulum results in blockage of release of vasopressin from hypothalamus to posterior pituitary. This results in increased thirst and increased urination. So the answer is C.a transection/disruption of the infundibulum