USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 37-year-old woman comes to your gynecology practice because she missed her last two periods and has noticed milky discharge coming from her breasts. She is on birth control, and a recent pregnancy test was negative. She has not experienced any hot flashes or headaches recently. If her condition remains untreated, which of the following symptoms is she most likely to experience?
Contributors:Sam Gillespie, BSc
Normally, the pituitary is a pea-sized gland, hanging by a stalk from the base of the brain.
It sits just behind the eyes near something called the optic chiasm, which is where the optic nerves cross.
Prolactin stimulates breast milk production.
Another group of cells are the gonadotrophs and they secrete two gonadotropic hormones - luteinizing hormone, or LH, and follicle-stimulating hormone, or FSH, both of which stimulate the ovaries in women which make estrogen and stimulate the testes in men which make testosterone.
It makes two key hormones, thyrotropin-releasing hormone which increases prolactin release, and dopamine, which inhibits the prolactin release and actually overrides the stimulatory effect of thyrotropin-releasing hormone.
Now, during pregnancy the anterior pituitary gland releases prolactin and the placenta releases human placental lactogen and progesterone, and all three of these hormones stimulate the growth of more glandular tissue in the breast to produce milk.
Prolactinomas are functional tumors, meaning they secrete high levels of prolactin, and they typically form when there’s a mutation in the lactotroph cells of the anterior pituitary that allows the cells to divide uncontrollably.
The key is in the size of these things. Prolactinomas that are less than 10 mm in diameter are considered microprolactinomas, whereas those greater than 10 mm are known as macroprolactinomas.
This can cause visual problems as well as affect a person’s ability to view things that are in the temporal, or the outermost portion, of the visual field in both eyes, and this is called “bitemporal hemianopia”.
Another name for this is tunnel vision because the center of your vision is clear but everything in the periphery is dark, kind of like looking through a tunnel, I suppose.
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