A 52-year-old woman with no significant past medical history…
A 52-year-old woman with no significant past medical history presents to your office complaining of fatigue, constipation, cold intolerance, and weight gain. She is presently on no medications. Her physical examination is notable for a dull facial expression, periorbital swelling, and coarse, dry skin. There is no thyromegaly. The most likely cause of this woman’s symptoms is: