Medically reviewed by Dr. Stacy Hengisman MD and Felice Ramallo MSRD.
Believe it or not, a butterfly-shaped gland that sits at the front of your throat, just above the voice box, is responsible for a large portion of your overall hormonal health. In fact, your thyroid is an organ that plays a major role in regulating metabolism, growth, and the development of the human body. From releasing hormones into the bloodstream, to deciding if you feel hungry, the thyroid gland makes sure your body ticks along as it should. But what if your thyroid is producing too much or too little of a certain hormone? What if it isn’t responding as it should to certain stimuli? That’s what we’ll be discussing in this article: what the thyroid does, how it does it, and symptoms that your thyroid may not be working as it should. From there we’ll discuss treatment plans and how to gain more control over your thyroid health. Let’s dive in.
What is the thyroid?
Like we mentioned earlier, the thyroid gland is a hormone gland. It sits at the front of your neck, and produces two hormones, triiodothyronine (T3) and thyroxine (T4). These hormones play a key role in regulating blood pressure, body temperature, heart rate, and metabolism. The thyroid is also in charge of producing calcitonin, which helps bone cells use calcium to build and strengthen bones.
Making T3 and T4
To understand what is going on when our thyroid starts acting up, let’s talk about the hormones that the thyroid is in charge of.
T3 and T4 are made in the follicular epithelial cells of the thyroid, and iodine is an essential “building block” of both hormones. Since our bodies can’t produce this iodine on their own, we rely on getting enough of this element through our food, which is then absorbed into our bloodstream from our bowel. This is the reason table salt has added iodine in the US, just look for “iodized salt.” From there, it is transported to the thyroid gland, where it’s converted (along with other things) into thyroid hormones.
The pituitary gland
Interestingly, our bodies don’t need a constant, unchanging supply of T3 or T4: sometimes we need more, sometimes less. This means the thyroid relies on another gland, specifically the pituitary gland, which notifies the thyroid of whether it needs to release more or less T3 and T4 into the bloodstream. The pituitary gland, located in the center of the skull (below your brain), is especially important because it monitors and controls the level of thyroid hormones in the bloodstream, adjusting the level of its own hormone output as a result. The pituitary gland produces thyroid stimulating hormone (TSH) which will be sent to the thyroid, letting the thyroid know how much to adjust levels.
And if you needed more evidence as to how cool this whole process is: thyroid hormones are attached to transport proteins in the blood, so if your body needs more thyroid hormone, T3 and T4 can be released from these same proteins into the bloodstream!
What the thyroid does
As we touched upon earlier, the thyroid makes T3 and T4, as well as calcitonin (made by C-cells), in order to aid the production of calcium and bone metabolism.
T4 is responsible for your metabolism, mood, and body temperature, while T3 is massively important to your digestive and metabolic function, as well as overall bone health. In the case of T3 or T4 being too low, the pituitary gland will try to compensate by releasing more TSH (while the opposite is true if T3 and T4 levels are too high).
Types of thyroid disorder
Most of the time, the thyroid is acting as it should, and our hormones are in balance (as well as the rest of our body). Unfortunately, there are several disorders associated with the thyroid, and all of these require collaboration with a physician to manage symptoms. Let’s walk through the most common ones.
Hyperthyroidism means your thyroid is too active, so your metabolism is working at a faster rate than normal.
Symptoms of hyperthyroidism include:
- Difficulty sleeping
- Tiredness and lack of energy
- Problems sleeping
- Weight loss
- Shaky hands
- Thinning skin
- Sweating more than usual
- Weak muscles
- Bulging eyes, due to weakened eye muscles
- Sensitivity to light
Causes of hyperthyroidism
Causes of hyperthyroidism can include Graves’ disease, a nodular goiter, and thyroiditis.
Beginning with Graves’ disease, this is an autoimmune disorder, and it is the most common cause of hyperthyroidism, according to Johns Hopkins Medicine. Specifically, Graves’ disease can be described as an autoimmune disorder, since your immune system makes an antibody called thyroid-stimulating immunoglobulin (TSI) that attaches to your thyroid cells, and it causes your thyroid to make too much thyroid hormone.
Another common cause of hyperthyroidism can be the presence of a toxic nodular goiter. This is when one or more lumps on the thyroid become too active. Unfortunately, health experts don’t know what causes this to happen.
Finally, we have thyroiditis: this is when your thyroid becomes irritated. It can temporarily cause the thyroid to become overactive (hyperthyroidism) for a short period of time, and then changes to become underactive (hypothyroidism).
Hypothyroidism is more common, and describes an underactive thyroid, and it essentially means your thyroid is not producing enough T3 and T4.
Symptoms of hypothyroidism include:
- Tiredness and fatigue
- Being cold easily
- Slow speech
- Weight gain
- Muscle cramps
- Hand tingling or pain
- Puffy and swollen face
- Thinning eyebrows (the sides may fall out)
- Increased or irregular menstrual flow in women
- Dry, brittle, or thinning head hair
So why do some people develop hypothyroidism and others develop hyperthyroidism? Well, scientists aren’t exactly sure, but they do believe hypothyroidism (like Graves’ disease, in the case of hyperthyroidism) is an autoimmune disorder. In this situation, your body makes antibodies that work against the thyroid gland.
In some cases, something called secondary hypothyroidism can occur: this is when your pituitary gland (the one we covered earlier, that sits in the center of your skull and produces TSH) stops working and it no longer instructs the thyroid gland to make thyroid hormones.
Hashimoto’s thyroiditis refers to a state in which your thyroid gland becomes irritated. Hashimoto’s is an autoimmune disease in which your thyroid experiences irritation through your body attacking the healthy tissues of the thyroid, which results in the death of the thyroid’s hormone-producing cells, and you not being able to produce enough T3 and T4.
Hashimoto’s has multiple symptoms, most of which overlap with those experienced by those diagnosed with hypothyroidism. Another symptom of Hashimoto’s might also be goiter; this is where your thyroid becomes enlarged. You may be able to see a slight bulge on your neck, and you can have problems swallowing or speaking.
Thyroid’s can sometimes develop nodules and adenomas, which are small and noncancerous growths. They start in the cell layer that lines the inner surface of the thyroid. Keep in mind that thyroid nodules are quite common in adults, with estimates indicating that 70% of Americans over the age of 70 have one or more (though they are rarer and more serious if found in teenagers or children, for instance). There are 4 types of nodules that could be found on the thyroid:
- These are benign buildups of thyroid cells
- Follicular adenomas
- These are also benign
- These are filled with fluid and found on the inside of the thyroid gland; they are rarely cancerous
- Thyroid cancer growth
- These can come in many forms, and as such, an ultrasound or biopsy are important in determining whether the growth is cancerous or not
- Of note, most thyroid cancers have a 5-year survival rate well above 90%.
Nodules and adenomas can trigger symptoms similar to those experienced by people who have hyperthyroidism. The nodule itself can produce thyroid hormone, and so you may have too much T3 and T4 in your system. Other signs of a nodule might include:
- Difficulty swallowing
- Voice changes, such as hoarseness
- Swelling in the neck
- Pain in the neck
- Visible goiter in the throat area
Diagnosing a thyroid disorder
Okay, so let’s say hypothetically you go to a doctor about some troubling symptoms that seem like hyperthyroidism, hypothyroidism, or even a potential goiter on the neck: what will the doctor do? How will they find out if your thyroid is acting normally or not?
There are three primary means your doctor may use to determine whether you have a thyroid disorder: blood tests, imaging tests, and a physical exam. Let’s walk through each in turn.
- Thyroid stimulating hormone (TSH)
- Most of the time, thyroid hormone deficiency (ie hypothyroidism) is associated with an elevated TSH level, while thyroid hormone excess (ie hyperthyroidism) is associated with a low TSH level. Makes sense, right? Your pituitary gland will signal to your thyroid to make more or less T3 and T4, depending on how much it has been monitored in the bloodstream, and it communicates these messages via TSH.
- Your primary care physician can also understand if you have an over or underactive thyroid from looking directly at your T4 levels to see if they fall within a ‘normal’ range.
- Free T4
- Different from measuring T4, free T4 eliminates the effect of proteins that naturally bind T4 and may prevent an accurate measurement.
- Low T3 can signal hypothyroidism, but it is often more useful in diagnosing hyperthyroidism, in which T3 levels are usually elevated.
- Free T3
- Like with free T4, free T3 allows doctors to eliminate any influence of proteins naturally binding to T3 that can affect getting an accurate measurement.
After running the above tests, your doctors can flag any irregularities in your bloodwork. From there, they may order the following tests:
- Thyroid antibodies
- These can help isolate the possibility of an autoimmune thyroid condition
- Useful for diagnosing C-cell hyperplasia and a type of thyroid cancer, this measurement helps rule out rare disorders
- This test gives more insight as to whether your thyroid is inflamed
- Thyroid scan
- Blood tests are extremely helpful in understanding how your thyroid is functioning, and whether it is outputting an excess of hormones, or not enough. At the same time, a thyroid scan can lend insight into any irregularities or changes to the size and shape of your thyroid, in addition to any nodules or growths on it.
- This diagnostic test is conducted by an ultrasound technician, who will use a device that transmits high-frequency waves through body tissue, and echoes are recorded and translated into video footage or a picture.
- In many cases, ultrasounds are preferable because they do not use radiation. They last about half an hour.
Finally we have the classic exam your physician might conduct on the same day you explain your symptoms. A physical exam is useful for determining any irregularities in the size and shape of the thyroid, as well as any potential growths. This exam is quick – typically just a couple of minutes in length – and painless.
Treating a thyroid disorder
Treatment will depend on what type of thyroid disorder you may have, as well as other factors such as age, overall health, and lifestyle choices.
That being said, if you have an overactive thyroid, the following treatments are typically considered:
- Antithyroid drugs
- These are drugs aimed at reducing the output of thyroid hormone from your thyroid.
- Radioactive iodine
- This treatment damages the cells of your thyroid, preventing it from successfully outputting so much T3 and T4
- Unlike the aforementioned treatments, this option is more about managing symptoms than reducing the output of thyroid hormone
- This is a surgical procedure in which your practitioner removes your thyroid. Since you will no longer have a thyroid to produce T3 and T4, as well as calcitonin, you will need to take thyroid replacement medication for the rest of your life.
- A thyroidectomy can be carried out by two methods, one of which involves an incision – as you might expect – at the front of your neck, while the alternative method is in your armpit. If your thyroid is enlarged or has lots of growths on it, the former approach may be better. The latter is carried out via an incision in your armpit, and a tunnel being created (via a tool called an elevated retractor) which leads to your thyroid. This procedure’s main benefit is that it’s ‘scarless,’ since the scar is out of sight, but it is more complicated for the surgeon and more invasive for you. On top of this, not every candidate is the right fit for this procedure. This is why it’s important to find a practitioner you trust, and who will take the time to walk you through the pros and cons of each treatment plan.
If you have an underactive thyroid, most treatments will be focused on increasing the output your thyroid naturally makes of T3 and T4. These include:
- Thyroid replacement medication
- This is a synthetic drug aimed at adding more thyroid hormones into your system
- This medication is taken by mouth, and should help reduce the symptoms of hypothyroidism
- You will likely start feeling better 1 to 2 weeks after beginning treatment, but know that treatment will be lifelong (though the dosage may change). Your provider should check your TSH levels annually to make sure the medication doesn’t lead your body to having too much thyroid hormone in it.
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