Hypothyroidism: Risks, Symptoms, and Diagnosis
"If you're experiencing these symptoms, go to your doctor and get screened for hypothyroidism."
Chronic fatigue, sudden weight fluctuations, hair loss, feeling cold all the time... these are just a few symptoms that could be signs of an under-active thyroid, also called hypothyroidism. On today's show with Dr. Keller Wortham, MD, we'll take a closer look at thyroid function and what happens when it's not functioning the way it should. Dr. Keller will explain it all, including the other symptoms of hypothyroidism, risk factors, how it's diagnosed, and how it can be treated.
- 00:45: The Thyroid Gland
- 02:40: The Thyroid Hormones
- 05:53: Hypothyroidism
- 07:16: Symptoms of Hypothyroidism
- 08:57: Primary Risk Factors For Developing Hypothyroidism
- 11:18: What Hypothyroidism Does to the Body
- 14:19: How Hypothyroidism is Diagnosed
- 17:20: Treating Hypothyroidism
- 18:49: Wrap-Up
The Thyroid Gland
The thyroid gland is a butterfly-shaped gland that sits right under the Adam's apple, around the neck, and it produces hormones that are vital for your metabolism. It helps us with development and growth, as well as a lot of our metabolic processes, by essentially charging and running the metabolism. Normally, you can't really feel the thyroid gland unless it's enlarged or has a problem.
The thyroid gland is referred to as an endocrine gland, which means that the thyroid gland secretes its hormones right into the bloodstream. There are other endocrine glands in the body like the adrenal glands, but the thyroid is really the one responsible for running our metabolism. This process of controlling and running the metabolism is very specific and very well controlled. The thyroid gland produces two primary hormones: one called thyroxine which is also referred to as T4 and one called triiodothyronine which is referred to as T3. Both of these hormones are dependent on a molecule called iodine to come in and help create the building blocks for thyroid hormone. That’s why it's very important to have iodine in our diets. Incidentally, in the U.S. there is iodine in our salt (that’s why it’s called iodized salt) just to make sure that people don’t end up with an iodine efficiency. It is very hard in the modern world to get an iodine deficiency, which in the past could have led to a thyroid hormone deficiency.
The Thyroid Hormones
T4 is produced primarily by the thyroid gland. T3 is also produced in the thyroid gland but it's also usually produced in other areas, and converted from T4 to T3 in the periphery. T3 is important because it’s the main active thyroid hormone. Now that conversion process of T4 to T3 can be affected by a lot of things going on in your body, including stress, starvation, different medications that you might be taking, and vitamin deficiencies (especially a vitamin D deficiency). All these things can affect that conversion from T4, which is less active hormone, to the more active T3.
Additionally, as far as regulating this very sophisticated process, most thyroid hormones circulating through our bodies are attached to proteins, which help control the thyroid levels, and help the hormones move around to other body parts, but when thyroid is bound to a protein it is not active. So only the parts that are referred to as free thyroid hormone are the biologically active thyroid molecules in our bodies. That thyroid element that’s bound to proteins allows us to really tightly regulate the thyroid hormone, and also to have a good-sized storage of thyroid hormone available that our bodies can reactivate, or activate at a moment's notice.
In addition to that, the thyroid hormone is very tightly regulated by something that's called a feedback loop. This is a really fascinating process. We can think of our thyroid as a furnace that's producing heat, and imagine the thyroid hormone as the heat coming out of this furnace. Then there's a gland in the brain called the pituitary, which we can think of as the thermostat. Basically what happens is, our thermostat resides in our brain and it tells our thyroid, the heater, how much heat (or thyroid hormone) to make. As our thyroid starts making that thyroid heat, then the heat gets out into our body, until the thermostat gets the message that enough heat has been produced, at which point the thermostat turns down the heater. So, you have this nice feedback loop of your brain telling your thyroid what to do, your thyroid creating this hormone and then that hormone circulating back up to your brain to tell it when to stop. When that process takes place properly, your metabolism is right where it needs to be, managing your growth, your cellular repair, your digestive function, and other things. However, if something goes wrong with the process, then your whole metabolism can collapse and you can end up with a lot of those symptoms that we mentioned in the beginning, as well as others.
One of the issues that can occur with the thyroid, is that it can stop producing enough hormones — that condition is called hypothyroidism. Hypothyroidism can happen for a variety of different reasons, but primarily it means that we don't have enough circulating thyroid hormone to take care of our body’s processes. The main reason this usually happens is something called Hashimoto's thyroiditis, an autoimmune condition where the body starts attacking the thyroid gland, and then that thyroid gland starts to really burn out because the cells that produce the thyroid hormone are being rendered non-functional. Hypothyroidism can also be caused by radiation, by an iodine deficiency (which is rare), because of a surgery that you've had in the past that removed part of your thyroid, or it can happen if someone's ever had hyperthyroid (the overproduction of thyroid hormones) and it was overtreated.
Symptoms of Hypothyroidism
Regardless of the reason, once you have that low-functioning thyroid you start to develop symptoms, including:
- Weight gain, because the thyroid regulates metabolism
- Low energy, because the thyroid is responsible for giving us energy
- A low heart rate. Your heart needs stimulation, and when the whole metabolism slows down, your heart rate might also slow down
- Hair loss
- Dry skin
- Constipation. Again, your gut is dependent on thyroid hormone, so, if your thyroid levels are very low, you can feel constipated.
- Irregular periods. If you are a woman, the thyroid is also very important in regulating your menstrual cycle.
So, if you’re experiencing any of these symptoms, you should talk to your doctor about the potential of having low thyroid function. Luckily, it’s a very easy thing to evaluate. It usually involves palpation of your thyroid — your doctor will see if he can feel an abnormal thyroid gland — or a blood test. Blood tests are also very very important for looking at the potential conditions that set you up for hypothyroid.
Primary Risk Factors For Developing Hypothyroidism
- Being Female — Unfortunately, just being female puts you at a higher risk for a lot of autoimmune diseases, including Hashimoto’s thyroiditis, one of the main autoimmune causes of low thyroid.
- Aging — Women over 60 years of age have a higher risk of developing hypothyroidism.
- Family history — If you've had a mom, an aunt, or a sister who's had thyroid problems, then your risk factors go up as well, especially if you're female.
- Autoimmune disorders of any kind — Any type of autoimmune disorder involves the body attacking itself. Since the number one cause of hypothyroidism is an autoimmune disorder, that can set you in that higher risk category even if it’s not specifically Hashimoto’s.
- Radiation of any kind — Certainly, if you've had radiation for cancer treatment or if you get a lot of exposure to radiation at work, it can really affect the thyroid gland. Incidentally, that's why, when your dentist does x-rays, they put something around your neck to protect your thyroid from radiation. It’s very very susceptible to radiation.
- Recent Pregnancy — If you're a woman who's been pregnant recently, your risk of thyroid disease, specifically hypothyroidism, goes up. There are some interesting theories about why that is: it's thought that being female, autoimmune diseases, and pregnancy may all be tied together, because when you're pregnant you have someone else inside of you and only half of their genes are yours. The other half comes from the child’s father. So your body might be on high alert and start reacting to all of these different cells and genes that are within your body but are not related to you. And that can set you up for an autoimmune condition that can later go on to attack your body. That's just one of the theories about why women might have a higher risk of autoimmune diseases and therefore of hypothyroidism.
What Hypothyroidism Does to the Body
So, what happens if you have hypothyroidism that remains undiagnosed? Well, it can set you up for some pretty serious complications.
The first is maybe not as severe as others. It's called goiter and that basically means that if you have an autoimmune process attacking your body's ability to make thyroid hormone, your thyroid itself can start to get larger and larger in an attempt to compensate for the fact it's not making good thyroid hormone, resulting in a mass around your neck. It's one of the first things your doctor will look at when checking to see if they can palpate the thyroid. If they can palpate it, that usually means it's larger than it's supposed to be, and that could be an indication of a low functioning thyroid. This enlarged thyroid can also start to put pressure on your neck, making it difficult to swallow, and even affecting the quality of your voice.
This can be another result of undiagnosed thyroid issues. As we mentioned earlier, your heart is very dependent on your thyroid hormone. If you're starting to get low levels of thyroid hormone, it can have affect the rhythm of your heart, as well as cholesterol levels in the body, making it so that the cholesterol levels are not as healthy for your body and for your heart. That, in turn, can lead to heart disease and a higher risk of heart attack and stroke.
Mood disorders and mental problems can also occur as a result of undiagnosed thyroid problems. Thyroid hormone is very important for stimulating the brain and keeping it going. People who have low thyroid hormones can get depressed more easily, and can start to experience mental fogginess and even an increased risk of dementia. So it’s very important to diagnose hypothyroidism for your nervous system and your brain.
Peripheral neuropathy has to do with the nerves that are coming out of your spinal cord and going to the various areas of your body. If your thyroid is functioning low for a long period of time, those nerves start to become damaged and you can lose sensation or you can get tingling in your different body parts and that can be quite serious, which can set you up for injury to those body parts.
Again, if your thyroid levels are low, your menstruation cycle can go off. For both men and women it can affect the health of the gonads where the sperm cells and eggs are produced, and that can really affect your fertility.
If you are pregnant, low thyroid hormone can lead to really severe birth defects in your child. This is why it’s very important for pregnant women to be screened for low thyroid. As we talked about, just being pregnant can increase your risk for thyroid disease, so make sure to get screened and diagnosed.
How Hypothyroidism is Diagnosed
As we already discussed, diagnosing thyroid issues involves palpation of the thyroid, and then blood tests. We’re going to go into more detail about a couple of the blood tests that your doctor would typically do.
The main tests a doctor would perform to screen for thyroid diseases is called a TSH, which tests thyroid stimulating hormone, which is produced in the brain. You might wonder why you’d check a hormone made in the pituitary, to find out what the thyroid is doing. Well, that's because the pituitary is that thermostat we talked about, which is trying to correctly set the heat of the thyroid. If your thyroid isn't working, and it’s shutting down, then that thermostat will think it’s way too cold in the body and try to turn up the heat, which will raise those levels of TSH (thyroid stimulating hormone) in an attempt to wake up the thyroid. And if the thyroid burns out, it's not going to be able to do that. So that TSH continues to rise — it should normally be between 2 and 4, but it can get up to 12, 13, or even as high as 20. That's a very easy way to diagnose a problem with a low circulating thyroid hormone.
You can also test the thyroid hormones directly. Your doctor can test T3 and T4, both the bound and free, to get a sense of what the thyroid proteins are doing and how much of the active free circulating thyroid is available. This will give them an idea of whether the thyroid is producing those hormones, and whether they are circulating in the appropriate amounts of free and bound.
Specifically for autoimmune thyroid disorders, the doctor can check a couple autoimmune markers. One is called TPO, which are thyroid peroxidase antibodies. That basically means looking for antibodies which your body makes that are attacking certain elements of the thyroid. If you have high levels of those antibodies, it can mean that you're actually dealing with an autoimmune process that's attacking your thyroid. You can talk with your doctor if it does look like you have autoimmune thyroid problems going on. There are some things you can do to reduce that autoimmune process and reduce inflammation in your body, so that you can spare the amount of thyroid that you have left. Unfortunately, a lot of times this process just continues on until it starts to burn out the thyroid.
And finally, there’s a blood test to check thyroglobulin levels. That's a test where we're looking at a certain other cell in the thyroid — it's not the thyroid hormone itself, but it's a matrix cell that lives there. If thyroglobulin levels are too high, it can indicate that there might be a cancer going on.
So those are just some blood tests that can be done to investigate hypothyroidism. All of this may sound scary, but if you are dealing with hypothyroidism, it's a very easy thing to treat.
If your thyroid burns out, you may end up needing to take a medication permanently — often that medication is a thyroid hormone substitute, either a T4 or T3 substitute. Levothyroxine is one of the most common treatments. But that doesn’t have to be a scary thing. It just means taking a pill every day to replace the hormone that your body's not making. When you look at the other things that are out there, other diseases that have a much worse prognosis or have treatments with terrible side effects, taking one pill every day doesn’t seem so bad. Luckily, most of the time with hypothyroidism we just have to replace that hormone that went away, and you'll feel back to normal — your metabolism will kick back up, your hair might grow back, and you won’t be subject to some of those more dangerous side effects of hypothyroidism like heart issues and nerve problems.
If you're experiencing fatigue, hair loss, weight gain, or some of the other symptoms we talked about, go to your doctor, get screened for hypothyroidism, and if you have it, don't worry. There are some really easy things we can do to take care of it. We hope that's reassuring and helpful.