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Thyroid Guide

Written by Ada’s Medical Knowledge Team

Updated on

The thyroid is a gland that forms part of the hormonal system. It produces thyroid hormones that are involved in important processes such as metabolism, heart rate, and growth and development.

As the thyroid gland is involved in such crucial processes, its health can considerably impact the body.

Thyroid conditions such as hyperthyroidism, hypothyroidism, auto-immune disorders, and cancers may all cause different symptoms. Fortunately, thyroid diseases are treatable, although they often require lifelong treatment.

You can read more about the different thyroid conditions, symptoms, and possible treatments as well as thyroid hormones like T4, T3 or TPO antibodies on this page and in the linked articles.

What is the thyroid, and why do we need it?

The thyroid is a small gland in the neck. It's shaped like a butterfly, consisting of 2 lobes that slightly wrap around the windpipe. The section where these 2 lobes connect is called the isthmus. There are also 2 parathyroid glands on the back of each lobe. These also produce important hormones.

The thyroid covers most of the cricoid cartilage, touching the thyroid cartilage with the upper part of its lobes. The thyroid and cricoid cartilages are important as they help protect the windpipe. 1 2 3 4

The thyroid is an integral part of your hormonal system, as it produces hormones that regulate crucial body functions such as metabolism, fertility, and heart rate. On top of that, thyroid hormones play a vital part in growth and development. The thyroid gland's main hormones are triiodothyronine (T3) and thyroxine (T4), also known as tetraiodothyronine. Besides these hormones, the thyroid produces calcitonin and reverse triiodothyronine (RT3). 5 6

The thyroid produces these hormones in response to signals sent from 2 other important hormonal glands, the hypothalamus and anterior pituitary gland. The thyroid also sends feedback to these glands, so they know which signals to send back to the thyroid. 5

Iodine is a trace element that's necessary for the production of thyroid hormones. When you do not get enough iodine from food sources such as iodized table salt, seafood, and vegetables, this could lead to underproduction and a deficiency of thyroid hormones. 5

What are typical thyroid disease symptoms?

Thyroid disease symptoms may depend on whether the thyroid is overly active, which is called hyperthyroidism, or underactive, which is called hypothyroidism.

With hyperthyroidism, people experience: 5 7

  • Tiredness
  • Nervousness and mood swings
  • Difficulty sleeping
  • Sensitivity to heat
  • A goiter, which is an enlarged thyroid gland
  • Irregular heartbeat
  • Tremors
  • Palpitations
  • Weight loss

With hypothyroidism, common symptoms are: 8 9 10

  • Tiredness
  • Sensitivity to the cold
  • Weight gain
  • Depression
  • Forgetfulness
  • Low libido
  • Irregular periods
  • Cessation of periods
  • Constipation
  • Dry skin
  • Low heart rate

With thyroid cancers, you may experience: 11

  • A painless lump in the neck area
  • Hoarseness that doesn’t improve
  • A sore throat that doesn’t improve
  • Difficulty swallowing
  • Swollen neck glands

What are thyroid nodules?

A thyroid nodule is a small lump on the thyroid, which is caused by an abnormal growth of thyroid cells. In some cases, these nodules can produce thyroid hormones, which can lead to hyperthyroidism. Thyroid nodules often go unnoticed if they don’t cause symptoms of hyperthyroidism.

When to worry about thyroid nodules?

Sometimes thyroid nodules can be felt or cause problems with swallowing or breathing. Usually, they're harmless, but in other cases, they can become cancerous. It’s always best to visit your doctor when you see or feel an enlargement in the throat area.

Thyroid nodules can be singular, meaning there's only 1 on the thyroid. When there are several nodules on the thyroid gland, it's called a multinodular goiter.

An enlarged thyroid is called a diffuse goiter and is often related to auto-immune conditions such as Hashimoto’s thyroiditis and Graves’ disease. The goiter can also grow down to the breastbone. In this case, it’s called a retrosternal goiter. 12

Which thyroid diseases exist?

Thyroid diseases can be divided into groups: 3

  • Hyperthyroidism and hypothyroidism. Hypothyroidism can be congenital, which means that it’s present from birth.
  • Thyroiditis, which is an inflammation of the thyroid gland.
  • Autoimmune processes, such as Graves’ disease and Hashimoto’s thyroiditis. Normally, your immune system detects viruses and bacteria that have invaded the body and attacks them. With autoimmune diseases, the immune system mistakes the body’s own healthy tissues for intruders and starts to attack them. Graves’ disease often goes hand in hand with thyroid eye disease. This is a condition where the immune system attacks the tissues behind the eye, causing bulging of the eyes and other eye symptoms. Despite the name, this condition can also occur without the thyroid being affected. 13
  • Thyroid cancer.

When should thyroid function be tested?

Thyroid function should be tested when you’re experiencing symptoms of hyperthyroidism or hypothyroidism.

This is done by means of a blood test, which checks the amount of thyroid-stimulating hormone (TSH) and T4 in the blood. Less frequently, blood work can also be used to check for the amount of T3 in the blood or to check for a condition called Hashimoto’s thyroiditis, which is a disorder where the immune system attacks the thyroid. 14

The thyroid should also be tested when you feel an enlargement in the throat area, if you have problems swallowing, or if you experience continuous hoarseness. Apart from blood work to check your thyroid hormones, a thyroid ultrasound may also be done to check whether you have an enlarged thyroid.

A thyroid biopsy is usually performed as well if the thyroid ultrasound confirms an enlargement that is suspicious. This biopsy is called a fine needle biopsy, which is where a few cells are taken from the enlarged thyroid using a fine needle and analyzed for anomalies. 11

What treatment is available for thyroid issues?

If you are diagnosed with a condition of the thyroid, your doctor will guide you through the best treatment options for your situation.Hypothyroidism and Hashimoto’s thyroiditis are characterized by low levels of thyroid hormone in the blood. Taking hormone replacement tablets can help with this. 15 16

Thyroid medication can also help with hyperthyroidism. Certain medications prevent the thyroid from producing too much thyroid hormone. Other ways to treat hyperthyroidism are radiotherapy to destroy some of the hormone-producing cells in the thyroid or thyroid surgery to remove the thyroid either completely or partially. 7

For other conditions of the thyroid, such as thyroid cancer, the treatment strategy depends on which type of cancer is present. Treatment options may include medication, surgery, and chemotherapy. 11

Thyroid FAQ

Q: What is a thyroid doctor called?

A: An endocrinologist is a doctor that specializes in the hormonal system and its conditions. Endocrinologists can help you with conditions of the thyroid.

Q: Are thyroid problems curable?

A: Thyroid problems are treatable, but they often require lifelong use of medication to keep a healthy level of thyroid hormones.

Q: Do thyroid problems run in families?

A: If you have a blood relative that suffers from a thyroid condition, then you'll have a greater chance of developing thyroid problems as well.

Q: What is a thyroid storm?

A: A thyroid storm is also known as a thyrotoxic crisis, and is a life-threatening complication of hyperthyroidism. During a thyroid storm, the thyroid suddenly releases large amounts of thyroid hormone.

Q: What happens if thyroid hormones are imbalanced?

A: Imbalanced thyroid hormones may lead to problems with metabolism, growth, and fertility.

Q: What are early warning signs of thyroid problems?

A: Early warning signs are fatigue, weight loss or gain without any known cause, and sensitivity to changes in temperature.

Q: How to prevent thyroid problems?

A: Thyroid problems may be prevented in some cases by maintaining a healthy diet with a sufficient amount of iodine. Avoiding alcohol and smoking is also beneficial.

Q: When is thyroid surgery necessary?

A: The thyroid, or a part of it, may be surgically removed in the case of hyperthyroidism, nodules, cysts, or cancer.