Endocrinology

PCP submission

82 year old female who has had weight loss on/off, has had elevated TSH with most recent one of 12.5 and FT4 1.4 but in the past has been asymptomatic. Pt is currently f/u with ENT and GI. She is also anemic and is on iron.

Given recent weight loss, would you recommend that I start her on low dose levo to target a more normal TSH. Question 2 is are there any other labs that I should order.

Specialist response

Great questions. The TSH level naturally rises with age, even in the absence of thyroid disease, so we’ve become more and more tolerant of mildly elevated TSH levels like what we’re seeing in your patient. The threshold at which patients unequivocally benefit from levothyroxine therapy is probably higher than we’re seeing in your patient, closer to ~20 mIU/L. In young people, many argue for a threshold of ~10 mIU/L. I’m notoriously conservative, but I think I would hold off on levothyroxine for now. I’d recheck her TSH in ~6 months, or sooner if her condition worsens. If her TSH level continues to rise, and especially if it becomes >20 mIU/L, I’d offer levothyroxine therapy. The ATA guideline recommends a target serum TSH to 4–6 mIU/L if we elect to start levothyroxine. I’m not sure any other labs would help us. We could check her TPO antibodies, but the result would be unlikely to change our care. Does that plan seem reasonable? If not, or if new questions or issues come up, please don’t hesitate to message me back. I hope this is helpful.