Question

A woman presenting with amenorrhea and galactorrhea is diagnosed with a pituitary adenoma and elevated prolactin levels. What is the most likely cause of her amenorrhea?

• A. Low GnRH
• B. High pulsed LH
• C. High FSH
• D. Inhibition of GnRH by prolactin

Hint:

Hyperprolactinemia causes amenorrhea by suppressing GnRH, leading to low LH and FSH.

Answer 1

The Correct Option is A

Concept: Hyperprolactinemia inhibits hypothalamic GnRH secretion. Reduced GnRH decreases LH and FSH secretion, leading to anovulation and amenorrhea.

Step 1: Identify the clinical syndrome.
Amenorrhea with galactorrhea and pituitary adenoma suggests: \[ \text{Hyperprolactinemia} \]

Step 2: Understand prolactin effect.
High prolactin suppresses GnRH secretion from the hypothalamus.

Step 3: Explain amenorrhea.
Low GnRH causes low LH and FSH stimulation of ovaries, resulting in anovulation and amenorrhea. Therefore, the correct answer is Low GnRH.