Recently a teenage girl presented with galactorrhea. A pregnancy test was negative. She was not using hormonal contraceptives, nor was she taking opiates or methyldopa. I ordered a serum prolactin and a thyroid-stimulating hormone (TSH) level. What further workup would you recommend? Should I check for marijuana, cocaine, or methamphetamine use? How common is malignancy in teenage girls?
—Felix Chien, DO, Newport Beach, Calif.

When galactorrhea occurs in a woman who is not postpartum or breastfeeding, the milky discharge is usually caused by elevated levels of prolactin. Since hypothyroidism can cause hyperprolactinemia, Dr. Chien correctly ordered assays of prolactin and TSH. Elevated prolactin levels are frequently caused by prolactin secreting pituitary adenomas. While these lesions are benign, a large tumor could compress the optic nerves and cause blindness.

Therefore, if serum prolactin levels are elevated and the TSH is normal, imaging studies of the sella turcica are indicated, even when the patient is a teenager. There is no evidence that marijuana, cocaine, or methamphetamine increases prolactin levels, but some tranquilizers, antidepressants, and antihypertensive drugs may increase prolactin levels and, in turn, cause galactorrhea.
—Daniel R. Mishell Jr, MD (105-12)

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