A 52-year-old man presents to the clinic with progressive difficulty seeing objects to either side while driving over the past several months. He reports frequently bumping into door frames and also notes decreased libido and fatigue. His medical history is otherwise unremarkable, and he does not take any medications. Physical examination reveals decreased peripheral vision bilaterally. Visual field testing demonstrates loss of the temporal visual fields in both eyes. MRI of the brain shows a sellar mass with suprasellar extension compressing the optic chiasm.
Which of the following additional findings is most likely present in this patient?
The correct answer is:
A) Decreased serum testosterone level
This patient has bitemporal hemianopia caused by compression of the optic chiasm from a pituitary adenoma. Pituitary adenomas commonly cause hypopituitarism due to compression of normal pituitary tissue, leading to decreased secretion of anterior pituitary hormones. In men, this often manifests as secondary hypogonadism with decreased luteinizing hormone and follicle-stimulating hormone secretion, resulting in low testosterone levels and symptoms such as decreased libido and fatigue.
Answer choice B: Ipsilateral ptosis and mydriasis, is incorrect. Ptosis and mydriasis are signs of oculomotor nerve compression, which typically results from posterior communicating artery aneurysms, not pituitary adenomas.
Answer choice C: Loss of nasal visual fields in both eyes, is incorrect. Compression of the optic chiasm affects crossing nasal retinal fibers, leading to loss of temporal visual fields, not nasal fields.
Answer choice D: Relative afferent pupillary defect, is incorrect. A relative afferent pupillary defect suggests unilateral optic nerve pathology rather than symmetric chiasmal compression.
Answer choice E: Unilateral optic disc edema, is incorrect. Papilledema from increased intracranial pressure is typically bilateral, and pituitary adenomas cause visual field deficits rather than optic disc edema.
Key Learning Point
Pituitary adenomas compress the optic chiasm, causing bitemporal hemianopia and often lead to hypopituitarism, including secondary hypogonadism in men.
