A 29-year-old nulligravid woman comes to the office due to a 6-month history of absent menstrual periods. Menarche occurred at age 12, and her menses were previously regular, occurring every 28 to 30 days. For the past several months, she has also noticed a bilateral milky nipple discharge that stains her undergarments. The patient reports feeling unusually sluggish, experiencing generalized muscle aches, and having difficulty concentrating at her desk job. She has gained 5 kg (11 lb) over the past year despite no change in her dietary habits. She has no chronic medical conditions and takes no medications. Vital signs include a blood pressure of 110/70 mm Hg, a pulse of 58/min, and a respiratory rate of 14/min. Her body mass index (BMI) is 26 kg/m². Physical examination reveals pale, cool skin and delayed relaxation of the deep tendon reflexes. A urine pregnancy test is negative.
Laboratory results are as follows:
| Laboratory Test | Result | Reference Range |
|---|---|---|
| Follicle-stimulating hormone | 4 mIU/mL | 5-20 mIU/mL |
| Luteinizing hormone | 3 mIU/mL | 5-20 mIU/mL |
| Prolactin | 82 ng/mL | <25 ng/mL |
| Thyroid-stimulating hormone (TSH) | 18.5 U/mL | 0.4-4.2 U/mL |
| Free thyroxine (T4) | 0.5 ng/dL | 0.8-2.7 ng/dL |
Which of the following is the most appropriate next step in management?
- AInitiation of cabergoline
- Initiation of levothyroxineCevap
- CMagnetic resonance imaging of the head
- DMeasurement of serum 17-hydroxyprogesterone
- EPelvic ultrasonography