Hypothyroidism, the condition of the thyroid gland not making enough thyroid hormone, is a common hormonal disorder. Perhaps because hypothyroidism is common and its symptoms can be widespread and vague, misconceptions abound. Let’s cover the facts.
Symptoms of hypothyroidism can include fatigue, dry skin, weight gain, and hair loss. These symptoms can occur for many other reasons, so fortunately a very simple blood test can tell us whether an underactive thyroid is the culprit.
If hypothyroidism is suspected, the best thing to test first is TSH, or Thyroid Stimulating Hormone. TSH is made by the pituitary gland in the brain which physiologically responds to levels of thyroid hormone circulating in the patient’s body. Under normal conditions, the pituitary gland signals the thyroid gland to make more thyroid hormone. So, if thyroid hormone levels are low, TSH levels will be high. The pituitary gland is trying to tell the thyroid gland, “wake up and make some more hormone, pal!”
If the TSH level is normal, in short, the thyroid is not the problem and probably no other testing needs to be done along those lines. If the TSH is elevated, another blood test for free T4 should be done. Free T4 is one type of thyroid hormone. Other types of thyroid hormones do exist but testing for them is far less reliable. In hypothyroidism, the TSH will be elevated, and the free T4 will be low.
Okay, so when we find a patient has hypothyroidism, what next? In general, we do not need to dig for a cause. Unless the person has had removal or ablation of the thyroid gland, we can assume they have Hashimoto’s thyroiditis, the most common reason for hypothyroidism. Hashimoto’s is an autoimmune disease which eventually destroys thyroid producing cells. Antibody testing is possible for Hashimoto’s disease, but it generally is not necessary.
Treatment of Hashimoto’s thyroiditis and any cause of hypothyroidism is simple…replace the thyroid hormone. This is done with a synthetic version of T4 hormone, the most reliable and standardized form of which is levothyroxine. Other types of thyroid replacement exist, but levothyroxine is universally recommended in all but a small minority of cases. Pretty much all patients can expect to take medicine indefinitely, though repeat TSH testing should be done periodically to make sure the dose is proper.
In summary, hypothyroidism is an easily diagnosed and easily treated condition. If you are having symptoms of this hormonal deficiency, discuss a TSH blood test with your primary care provider to see if a simple intervention might help you feel better.
Kelly Evans-Hullinger, M.D. is part of The Prairie Doc® team of physicians and currently practices internal medicine in Brookings, South Dakota. Follow The Prairie Doc® at www.prairiedoc.org and on Facebook featuring On Call with the Prairie Doc® a medical Q&A show celebrating its twentieth season of truthful, tested, and timely medical information streaming live on Facebook most Thursdays at 7 p.m. central.
