A 29-year-old woman comes to the office due to amenorrhea. She has not had a menstrual period since an uncomplicated vaginal delivery 13 months ago. The patient stopped breastfeeding 7 months ago but still has some milky discharge from both breasts. She has no other symptoms. The patient has a 10-year history of hypothyroidism, for which she takes levothyroxine, the dose of which was increased during her pregnancy.
On breast examination, bilateral milky discharge is expressed. There are no palpable masses, skin changes, or axillary lymphadenopathy. The remainder of the physical examination is normal.
Laboratory results are as follows:
Urine pregnancy test is negative.
Which of the following is the most appropriate next step in management of this patient?

Question

A 29-year-old woman comes to the office due to amenorrhea.  She has not had a menstrual period since an uncomplicated vaginal delivery 13 months ago.  The patient stopped breastfeeding 7 months ago but still has some milky discharge from both breasts.  She has no other symptoms.  The patient has a 10-year history of hypothyroidism, for which she takes levothyroxine, the dose of which was increased during her pregnancy.
On breast examination, bilateral milky discharge is expressed.  There are no palpable masses, skin changes, or axillary lymphadenopathy.  The remainder of the physical examination is normal.
Laboratory results are as follows:
 Urine pregnancy test is negative.
Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

11ec193a_97d7_2715_853d_db32c2de8be9_MD0002_00 Prolactin levels naturally increase during pregnancy due to stimulation from high estrogen levels, peak at delivery, and then normalize within 1-2 months after delivery, even with continued breastfeeding. Although prolactin levels increase transiently above basal levels with response to suckling, this response significantly diminishes a few weeks after delivery. This patient is no longer breastfeeding and is not currently taking any medications (eg, antipsychotics) that would explain increased prolactin levels. The most likely cause of this patient's elevated prolactin is a prolactinoma (ie, lactotroph adenoma). Prolactinomas can present with secondary amenorrhea, bilateral milky nipple discharge (ie, galactorrhea), and hypogonadism. A significantly elevated prolactin (>200 ng/mL) level usually indicates a prolactinoma. In any patient who has hyperprolactinemia and is not taking any medication known to increase prolactin levels, an MRI of the head should be performed to screen for a pituitary mass (Choice D). Additional evaluation of prolactinomas includes formal visual field testing due to the potential for the pituitary mass to compress the optic chiasm. Prolactinomas that cause hypogonadism (eg, amenorrhea) or neurologic symptoms (eg, headaches, visual disturbances) secondary to mass effect are treated first-line with dopamine agonists (eg, cabergoline, bromocriptine) and followed with serial MRIs. Surgery (eg, transsphenoidal resection) is reserved for patients who fail medical therapy. (Choice A) Patients with nipple discharge may require breast imaging (eg, ultrasound, mammogram) to evaluate for malignancy. However, breast cancer is associated with unilateral serous or serosanguinous discharge. This patient's markedly elevated prolactin level and bilateral nipple discharge make prolactinoma a more likely diagnosis. (Choice C) A progestin withdrawal test (ie, medroxyprogesterone for 5-10 days) induces menstrual bleeding in patients with amenorrhea if there is sufficient estrogen priming of the endometrium. This patient may or may not bleed following medroxyprogesterone depending on her estrogen status, but this would not address the hyperprolactinemia. (Choice E) Hypothyroidism leads to high thyrotropin-releasing hormone (TRH), which stimulates prolactin release and causes mild hyperprolactinemia. Although this patient's TSH is slightly elevated, mild hypothyroidism does not cause a markedly elevated prolactin level of >200 ng/mL. In addition, serum TSH is the most sensitive test to diagnose hypothyroidism and monitor response to levothyroxine therapy and therefore can be used alone to adjust dosage without checking total T4, free T4, or free T3 levels. Educational objective: Pituitary prolactinomas (ie, lactotroph adenomas) present with galactorrhea, amenorrhea, and hyperprolactinemia. A prolactin level >200 ng/mL usually indicates a prolactinoma. Diagnosis is confirmed via MRI of the head. First-line treatment is with dopamine agonists (eg, cabergoline, bromocriptine). __________ References: Diagnosis and treatment of pituitary adenomas: a review. (http://www.ncbi.nlm.nih.gov/pubmed/28170483) Menstrual cycle abnormalities in patients with prolactinoma and drug-induced hyperprolactinemia. (http://www.ncbi.nlm.nih.gov/pubmed/28670538)

A 29-Year-Old Woman Comes to the Office Due to Amenorrhea