Here’s Everything You Need to Know About Your Thyroid

thyroid issues

Dr. Brightman explains what your thyroid is, and how to know if it’s working correctly

The thyroid might seem like the Goldilocks of body parts — sometimes overactive, sometimes underactive, and sometimes just right. But how exactly do you know if your thyroid is in tip-top shape? And what role does it play in our bodies, exactly? Our resident women’s health expert, Dr. Rebecca Brightman, breaks down everything you need to know about this gland — which has a lot more control over your system than you might think.

KCM: So first tell us — what exactly is the thyroid? 

Dr. Brightman: The thyroid is a gland in the neck that both men and women have. It’s in front of the trachea and esophagus, and it produces hormones that basically impact every organ system in the body — it’s responsible for maintenance of body temperature, metabolism, and heart rate.  

It seems like the two main issues are typically that you’re producing too much or too little thyroid hormone. What is the difference between hyper- and hypothyroidism?

Hypothyroidism, or an underactive thyroid, happens when the thyroid isn’t producing enough active hormone. Symptoms include fatigue, weight gain, dry skin, and you may be more likely to feel cold, and have constipation. Hyperthyroidism, or an overactive thyroid, has symptoms that are almost the opposite. You may feel your heart racing. There also may be noticeable changes in the eyes — an abnormal protrusion of the eyeball or eyeballs called exophthalmos. Not everybody with hyperthyroidism exhibits this symptom, of course. But you are likely to feel very jittery, nervous, you may feel your heart is racing, and you may experience weight loss.

In women, both hyper and hypothyroidism can also be associated with menstrual irregularities. One of the general rules of thumb is that, if a young woman comes in with irregular menstrual periods, we always check for thyroid function. But thyroid issues can occur in both men and women.

Around what age do people usually start developing a thyroid issue? 

There’s something called congenital hypothyroidism, where a baby is born with an absent thyroid. That’s very concerning. This would be found in a newborn screening test. This needs to be detected immediately, because while a baby is in utero, it can get some thyroid hormone from the mom. But once the baby is born, if their thyroid isn’t working, they’re at a greater risk for impaired neurological development. So it’s essential that babies be screened.

More typically, I would say onset is in your twenties or thirties, but it’s sometimes diagnosed earlier. 

Which one is more common, hyper- or hypo-?

Underactive, or hypothyroidism, is much more common. This presents at around age 20 to 30. Hyperthyroidism, when the thyroid makes excessive amounts of thyroid hormone, is most common in women between 20 and 40, but it can occur really at any age, both in men and women.

What are the dangers of both of these conditions? 

Typically with an underactive thyroid, the thryoid is enlarged. An underactive thyroid can cause extreme fatigue, changes in weight, lethargy, hair loss, dry skin, and sometimes an enlargement in their neck. Hypothyroid is generally easily treatable with hormones. But thyroid hormone is not for weight loss. I think perhaps a generation or two ago it was given to people for weight loss, but we know that over-treatment of thyroid medicine can result in thinning of bones. 

When people do take thyroid hormone replacement, their requirements will change with age, as well as hormonal changes like going on and off birth control pills, pregnancy, being postpartum, or during the menopausal transition. 

In the long term, having a slightly underactive thyroid is unlikely to be lethal. That said, if you have severe and advanced hypothyroidism, known as myxedema, it can lead to an extreme drop in blood pressure, heart rate and body temperature that could cause a coma or even death. 

The dangers of having an overactive thyroid include sweating, profound weight loss, and rapid heartbeat. It’s not healthy for the heart to be beating like that. There’s something called thyroid storm that can happen, when — all of a sudden — a ton of thyroid hormone starts circulating in the bloodstream, and your heart rate, blood pressure, and even body temperature rise rapidly. If untreated, this can be fatal. The treatment for hyperthyroidism is a bit more complex, and may require radiation or surgery. 

How does a doctor treat and evaluate these issues?

We always do an exam of the thyroid. Some people have a thyroid that’s uniformly large, and sometimes we feel nodules, but either way, any abnormality needs to be evaluated through a blood test and frequently an ultrasound as well. Nodules are very common — they’re growths in the thyroid gland that are like solid or fluid-filled lumps. Most of them are benign and don’t cause symptoms, but probably about 5% of the time, they are not benign. So if you have thyroid nodules, you need to be evaluated, because in rare circumstances they can be cancerous. 

This interview has been edited and condensed