Dear Dr. Roach: My thyroid gland was removed due to cancer in 2007. Since then, there have been continuous prescription changes while trying to find an effective dose.
I am a 58-year-old woman, and menopause seemed to interrupt a correct dosage a few years ago. Why do I exhibit signs of hypothyroidism while taking Synthroid?
I take the medicine as prescribed, but still have dry skin, low energy, weight issues, etc.
I seem to have no metabolism at all. Diet and exercise have little impact on the scale.
Will diets and exercises that claim to boost metabolism work for me? Whenever I exercise or perform a physical activity, I require a nap due to fatigue.
S.L.
After thyroid cancer surgery, there usually is no significant thyroid tissue left at all and the body needs replacement hormone for proper metabolism.
When the body can鈥檛 make thyroid hormone, whether due to surgical absence or to thyroid disease such as Hashimoto鈥檚 thyroiditis, the body responds by increasing the level of thyroid-stimulating hormone from the pituitary gland, which is a signal for the thyroid to become more active.
The lower the thyroid hormone level, the higher the TSH.
After surgery for cancer, most experts want the TSH level to be low, in order to avoid stimulating any thyroid cells that might be left after surgery, so the dose of thyroid replacement is on the high side.
That鈥檚 why I am concerned about you having symptoms of low thyroid hormone.
Occasionally, I see people who do poorly on levothyroxine (also called T4, and sold under brand names such as Synthroid) but do well with a combination of levothyroxine and triiodothyronine (also called T3, sold by itself as Cytomel or in combination with T4, such as Armour thyroid).
A very few people cannot properly convert the T4 into the more active form T3, which may explain this phenomenon. I have seen far more people than I ever expected get symptomatic improvement by adding a small dose of T3.
However, it鈥檚 also possible that your fatigue is not at all thyroid-related. The fact that you get worse and need a nap after exercise suggests the diagnosis of chronic fatigue syndrome, also called systemic exertion intolerance disease. This condition requires an experienced provider to diagnose and treat properly.
Although special diets frequently are prescribed, there is no high-quality published data to support any particular diet.
Exercise regimens, though often effective when used under supervision, must be used with caution so as to avoid making the problem worse.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected].
