A 34-year-old man comes to the physician because of frequent headaches and blurry vision during the past 4 months. He has also had difficulties achieving an erection over the past few weeks. Medical history is unremarkable, and he takes no medications. He does not use tobacco, alcohol, or illicit drugs. Physical examination shows a temporal visual field deficit bilaterally. An MRI of the brain shows an intrasellar mass. Which of the following changes in serum GnRH, LH, and testosterone are most likely to be found in this patient?

Question

A 34-year-old man comes to the physician because of frequent headaches and blurry vision during the past 4 months. He has also had difficulties achieving an erection over the past few weeks. Medical history is unremarkable, and he takes no medications.  He does not use tobacco, alcohol, or illicit drugs. Physical examination shows a temporal visual field deficit bilaterally. An MRI of the brain shows an intrasellar mass. Which of the following changes in serum GnRH, LH, and testosterone are most likely to be found in this patient?

Quizplus · Accepted Answer

Eductional Objective: Large prolactin-secreting pituitary tumors can compress the optic chiasm, causing bitemporal hemianopsia.  In addition, elevated prolactin levels suppress release of GnRH, leading to decreased LH secretion and subsequently impaired testosterone production in men.

A 34-Year-Old Man Comes to the Physician Because of Frequent