Feeling unusually tired, depressed, or nervous? Are you experiencing unexplained hot flashes, changes in your menstrual cycle, or weight fluctuations? These symptoms may be due to thyroid abnormalities. Dr. Judith Reichman was invited to appear on “Today” to help us understand the workings of the thyroid — the gland “that rules the body” — works, and what can happen if it doesn’t function properly.
If your thyroid is working as it should, you won’t even realize that you have one. But if it isn’t, you’ll definitely notice it. If the gland doesn't make enough hormones, this is called hypothyroidism, a condition which causes your metabolism to slow down. And if your thyroid makes too much, it will cause hyperthyroidism, a condition that causes your metabolism (you guessed it) to speed up.
What is the thyroid gland?
The thyroid is a butterfly-shaped gland found at the base of your Adam’s apple. It secretes the hormones that influence the growth and development of all your tissues, and regulates metabolism for your entire body. These hormones, T3 (triiodothyronine) and T4 (thyroxine), are the only ones in your body that contain iodine. T4 is the primary product of thyroid secretion. Once T4 is in the body’s tissues, its iodine portion is removed and it becomes T3. This is the biologically active thyroid hormone that enters the cells and “does its thing.”
Production and secretion of the thyroid hormones is controlled by another hormone, one that is produced in the pituitary gland of the brain. This is aptly called the thyroid-stimulating hormone (TSH). If the pituitary gland and the brain center that controls its hormone production sense that there’s too much T3 and T4 in the body, it ceases to make and release TSH. To determine thyroid activity, we can either measure T3 and T4 levels in the blood or we can measure TSH. Low levels of TSH will occur when T3 and T4 are too high. High TSH means the pituitary gland is working hard to try to elevate T3 and T4 levels in an inadequately responsive thyroid.
Who is at risk for hypothyroidism?
In the U.S., the most common cause of hypothyroidism is a chronic autoimmune disorder (that’s when the body’s antibodies attack the thyroid gland) called Hashimoto’s disease. You’re at risk if you have a family history of thyroid disease, if your thyroid becomes enlarged (this may be due to an inflammation called thyroiditis), if your thyroid develops an irregular shape (due to a benign growth or goiter), or if you have an autoimmune disorder such as lupus or rheumatoid arthritis.
Hypothyroidism is 10 times more likely to affect women than it is men. It occurs in 4 percent to 11 percent of all women. The female prevalence of this disorder may have to do with our fluctuating hormones during puberty, periods, pregnancy, and peri-menopause. Changes in estrogen and progesterone may also trigger an autoimmune reaction so that antibodies mistakenly attack and destroy thyroid tissue. This is more likely to occur as we get older and after pregnancy (especially in diabetic women). In as many as 5 percent of postpartum women, the thyroid may undergo nonspecific inflammation (thyroiditis) and, at least for a short period of time, produce inadequate amounts of thyroid hormones. In some cases, the thyroid remains slow (symptoms that mimic postpartum depression may persist) and therapy is needed.
What are the symptoms of hypothyroidism?
- Weight gain from fluid retention
- Cold intolerance
- Dry skin
- Coarseness and loss of hair
- Memory and mental impairment
- Decreased concentration
- Irregular or heavy periods, or infertility
- High cholesterol
- Symptoms that mimic those of menopause
Hypothyroidism can directly affect the central nervous system, cellular metabolism, utilization of glucose, the inner thermostat, bowel function, and production of lipids. It can cause the skin to lose water content. Because of the central nervous system effects and the general slowing down of metabolism (and weight gain), depression may follow. Appropriate amounts of the thyroid’s hormones are necessary for regular ovulation, cycles, and fertility. An insufficiency disrupts these functions.
How is the diagnosis made?
A simple blood test can check the level of TSH. (Remember an elevated TSH means that the pituitary is working harder to get the thyroid to produce hormones.) Once an elevated TSH level is found, other tests may be done, including those for T4, T3, and a free thyroxin index or FTI (most thyroid hormone is bound up by protein as it circulates, and only the unbound portion enters the cells to “do its work.” This test measures the unbound portion). The latter tests help evaluate the actual working levels of thyroid hormones.
Who should be tested?
Currently, most of the endocrine societies recommend that a woman have her TSH levels checked if she is symptomatic, has a family history of thyroid disorders, has an autoimmune disorder such as diabetes, or has high cholesterol. Testing is also recommended if a woman is in the early months of pregnancy and has a previous history of autoimmune conditions or obstetrical complications, such as recurrent miscarriage or early labor.
There is still some controversy as to whether there should be routine prenatal screening in women with no symptoms. There is a condition called pre-clinical hypothyroidism, where the TSH levels are somewhat elevated, but the FTI and T4 levels have not diminished below normal amounts. (In other words, the pituitary is working harder to get the thyroid to do its thing, and it’s still managing to do so.) Yet these women usually have no symptoms.
How do you treat hypothyroidism?
It’s not clear that those individuals with sub-clinical hypothyroidism should be treated. Many physicians believe that in the long term, if TSH is moderately elevated, even in the absence of currently low thyroid levels, a woman should be treated as soon as it’s diagnosed. Others believe, that a wait-and-see attitude should be taken, and that evidence-based medicine does not “bear witness” to an indication to start therapy before thyroid levels fall. However, if a woman has symptoms and/or her thyroid function is low, all physicians agree that therapy should begin.
What about hyperthyroidism?
This is most commonly seen with Graves' disease, an autoimmune disorder in which an immunoglobulin (an immune protein) acts on TSH to increase thyroid stimulation. This disorder affects about 2 percent of women during their lifetime and, again, is much more common in women than in men.
- Heart palpitations
- Heat intolerance
- Increased bowel movements
- Light or absent menstrual periods
- Trembling hands
- Weight loss (or weight gain because of nervousness and overeating)
- Muscle weakness
- Hair loss
- A staring gaze
- Bulging eyeballs
Hyperthyroidism usually begins between the ages of 20 and 40. It is diagnosed with a blood test for TSH, which will be abnormally low. Further tests should then be run to show that T3 and T4 also are elevated. An iodine thyroid scan should also be performed to see if the cause is a single nodule, or the entire thyroid.
Does hyperthyroidism have other health effects?
The chief concern is cardiovascular. There is a much higher risk of developing irregular heart beats, especially arterial fibrillation which can lead to stroke and heart attack. Excess thyroid activity can also cause bone breakdown; even sub-clinical hyperthyroidism can lead to osteoporosis.
How is hyperthyroidism treated?
If your physician feels that your condition is due to a sudden inflammation of the thyroid (you may have pain in the neck where the thyroid is located or even have a mild fever), she may elect to simply calm down the tremor and nervousness with beta-blockers and add anti-inflammatory medications until the inflammation resolves (and the symptoms dissipate). However, if overproduction of thyroid continues, you will need specific drugs.
If the patient stops taking the medication, the thyroid will overproduce hormones once again. As a result, many physicians advise patients that their hyperthyroid condition be “taken care of for good” with radioactive iodine. Thyroid cells are the only cells in the body that can absorb iodine. When the iodine is radioactive, it destroys these cells and their ability to overproduce hormones. The most common side effect is that the thyroid makes too little hormones, and the patient will need to take medication for hypothyroidism. Finally, if the patient has a goiter or nodule that is still overactive, surgery may be necessary.
Dr. Reichman’s Bottom Line: Fatigue, weight gain, constipation, depression, memory problems, cycle changes, nervousness, and heart palpitations are each very common symptoms of thyroid problems. These symptoms may also be caused by psychological, social and other medical situations — however, none of these symptoms should be ignored. Thyroid testing may give you the answer and the wherewithal for therapy that can change your life and health.
Dr. Judith Reichman, the “Today” show's medical contributor on women's health, has practiced obstetrics and gynecology for more than 20 years. You will find many answers to your questions in her latest book, "Slow Your Clock Down: The Complete Guide to a Healthy, Younger You," which is now available in paperback. It is published by William Morrow, a division of HarperCollins.
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