January 13th, 2009

flasks

delicious thyroid!

So now I'm terribly curious about whether or not I'm hypothyroid. I looked up the list of symptoms and could easily tick off more than half of them. I've been very tired all winter - unusually so even considering that I have SAD and chronic fatigue - and excessively cold, having to wear far more layers of clothes than other people just to stay warm enough. My skin has been very dry for months even before the itching started and despite all the cream and lip balm I use, and I've just noticed this week that my hair is falling out more than usual. I've also had concentration problems, total lack of motivation, weight gain and absolutely no sex drive - though these could be due to depression.

The problem is this: my TSH has gone from 3.81 uIU/mL in August to 5.16 uIU/mL now - but this is only just outside the range for "normal" in the UK, and the doctor's computer isn't bothered because it knows that carbamazepine can cause a falsely high TSH reading. So I did some research, and it seems that carbamazepine can mess up the results for just about all of the thyroid hormones (if the link breaks, it's pages 1253-1254). It can cause falsely high TSH and TBG (Thyroxine-Binding Globulin), and falsely low triiodothyronine (T3) in serum. And it can cause both falsely high and falsely low free thyroxine (T4) in serum! How do you actually confirm hypothyroidism if a medication you're on can mess up all the numbers?

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