What Is A Thyroid: Causes, Symptoms & Treatment?


Your thyroid produces hormones that play a vital role in many different systems throughout your body. When the thyroid produces too much or too little of these essential hormones, it’s called thyroid disease. 

What Is The Thyroid Gland?

The Thyroid Gland

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The thyroid gland is butterfly-shaped in the front of the neck. It is located below the voice box and wrapped around the windpipe (trachea). The thyroid produces hormones that control how quickly your body uses energy, creates proteins, and handles how sensitive your body is to other hormones.

The thyroid gland comprises follicles encased by a layer of fibrous connective tissue. The small, peg-like projections from the surface of the thyroid serve as sites for blood vessels and nerve fibres.

What Does A Thyroid Gland Do?

The thyroid gland discharges hormones that regulate the rate of chemical reactions in cells. Some of these chemicals are used by cells to produce heat and energy. They also regulate protein production and break down certain substances in food. These hormones also control how sensitive the body is to other hormones.

What Does A Thyroid Gland Do?

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The thyroid gland makes thyroxine (T4) and triiodothyronine (T3) synthetic versions of iodine-containing substances called thyroid hormones. These two hormones function together to regulate metabolism, or how quickly your body uses energy. 

Thyroxine is produced from tyrosine, which is converted from phenylalanine. T4 acts on the peripheral tissues like the heart, muscles, skin, and brain. T3 has a greater effect on cells in the target organ, like the liver, heart, and brain.

Types Of Thyroid Disorders

Thyroid disorders affect the thyroid gland. There are many different types of thyroid disease. These may include:

  • Hyperthyroidism
  • Hypothyroidism
  • Thyroiditis
  • Hashimoto’s thyroiditis
  • Goiter 
  • Thyroid nodules
  • Thyroid cancer

Types Of Thyroid Disorders

Source: Verywell

1. Hypothyroidism

Hypothyroidism is the second most common thyroid disease, with an estimated 1.8 million people in the US experiencing hypothyroidism. Hypothyroidism emerges when the thyroid gland does not create enough thyroxine to meet your body’s needs. 

A decreased production of hormones characterizes this compared to normal levels. It can cause symptoms like fatigue, breathing difficulties, and weight gain.

2. Hyperthyroidism

Hyperthyroidism is the most common thyroid disease, with an estimated 2.6 million people in the US experiencing hyperthyroidism. An increase in your thyroid hormones characterises it compared to normal levels. 

Hyperthyroidism occurs when your thyroid gland produces too much thyroxine, and the thyroid gland is overactive. This may cause a wide range of symptoms, including anxiety, increased heart rate, and weight loss.

3. Thyroiditis And Hashimoto’s Thyroiditis

Hashimoto’s thyroiditis is the most familiar cause of hypothyroidism, with an estimated 3.3 million people in the US experiencing it. Thyroiditis is caused by inflammation of your thyroid gland, which can disrupt its function. This condition can also cause symptoms like weight gain and fatigue.

4. Goiter

Goiter, or enlarged thyroid, is an abnormal gland enlargement that includes tissue swelling in front of the trachea and a lack of tissue behind the trachea containing lymph nodes.

5. Thyroid Nodules

Thyroid nodules are non-cancerous growths on the thyroid gland. They can be asymptomatic, or they may induce pain and pressure in the neck, difficulty swallowing, hoarseness, and shortness of breath.

Nodules are not cancerous, but they can interfere with thyroid function. If you have a nodule causing symptoms, you should see your doctor for an evaluation.

6. Thyroid Cancer

It is a type of cancer that evolves in the thyroid gland. It is the most common type of endocrine cancer and accounts for about 1% of all cancers in the United States.

Thyroid cancer arises when cells in the thyroid gland change or mutate, causing uncontrolled growth. These cells can invade nearby tissues and spread to other parts of the body, where they might continue to grow and form new tumors.

Thyroid cancer is typically treated with surgery to remove all or part of the thyroid gland, followed by radioactive iodine treatment or other forms of therapy.

Who Is Affected By Thyroid Disease

Who Is Affected By Thyroid Disease

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Many factors contribute to the development of thyroid disease. Some people are born with an underactive or overactive thyroid gland that is genetically inherited or caused by an autoimmune disorder.

The other common risk factors include:

  • Genetics
  • Radiation
  • Exposure to PCBs and other environmental chemicals
  • Iodine deficiency (which can be caused by inadequate intake of thyroid-supportive foods or a pro-iodide deficiency)
  • Autoimmune disease
  • Family history

People with thyroid problems are more likely to be diagnosed with other health issues. For example, people with thyroid disease are at a higher risk of developing diabetes.

People with thyroid problems are also more likely to develop mental health issues such as depression, anxiety, and bipolar disorder. It is possible that the thyroid hormone imbalance could cause these disorders or vice versa.

Causes Of Thyroid Diseases

Causes Of Thyroid Diseases

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The thyroid gland produces two main hormones: triiodothyronine (T3) and thyroxine (T4).

A) Causes Of Hypothyroidism

Hypothyroidism occurs when there is not enough T4 and T3 in the blood. The primary cause of hypothyroidism is an autoimmune condition called Hashimoto’s disease, which causes inflammation in the thyroid gland.

  • Hashimoto’s Thyroiditis

This is a manageable and painless disorder. It can affect the thyroid gland. It is an autoimmune condition. It happens when the body’s cells attack and damage the thyroid. It is an inherited condition.

The other conditions that cause hypothyroidism are:

  • Thyroiditis

It is an inflammation of the thyroid gland. This condition can lower the number of hormones it produces.

  • Postpartum Thyroiditis

This condition arises in 5% to 9% of women after childbirth. It’s usually a temporary condition.

  • Iodine Deficiency

The thyroid uses iodine to produce hormones. An iodine deficiency is a problem that affects several million people worldwide.

  • A Non-Functioning Thyroid Gland

Sometimes the thyroid gland does not work correctly from birth. This affects 1 in 4,000 newborns. If left untreated, they can have both physical and mental issues in the future. All newborns are screened for this during their stay at the hospital.

Besides the aforementioned causes, radiation exposure from nuclear disasters or accidents and medicines such as lithium, amiodarone, or interferon-alpha can also cause hypothyroidism.

B) Causes Of Hyperthyroidism

Hyperthyroidism occurs when there is too much T3 and T4 in the blood. The most common cause of hyperthyroidism is Graves’ disease, which can be caused by the body’s immune system attacking the thyroid gland.

  • Graves’ Disease

The thyroid gland might be overactive and produce excessive hormones in this condition. This condition is also called diffuse toxic goiter (enlarged thyroid gland).

The other conditions that cause hyperthyroidism are:

  • Nodules 

Overactive nodules within the thyroid can cause hyperthyroidism. A single nodule is a toxic autonomously functioning thyroid nodule, while a gland with several nodules is a toxic multi-nodular goiter.

  • Thyroiditis 

In thyroiditis, the thyroid releases hormones that are stored there. This can stay for a few weeks or months. This disease can be either painful or not felt at all.

  • Excessive Iodine

When you have excessive iodine (the mineral used to make thyroid hormones) in your body, the thyroid produces more thyroid hormones than it needs. Excessive iodine can be found in some medications (amiodarone, a heart medication) and cough syrups.

Besides the aforementioned causes, radioactive iodine to treat a previously-diagnosed thyroid nodule or goiter can also cause hyperthyroidism.

Symptoms Of Low & High Thyroid Levels

The symptoms of high and low thyroid levels can often be confused for one another because they share many similar symptoms. However, there are a few distinctions between the two that you should know. Many symptoms can be attributed to either hypothyroidism or hyperthyroidism, but some are more common in one than the other.

Symptoms Of Low Thyroid (Hypothyroidism) Levels

  • Weight gain
  • Fatigue
  • Hoarse voice
  • Constipation
  • Hair loss
  • Dry hair
  • Depression
  • Forgetfulness
  • Difficulty concentrating
  • Intolerance to cold temperatures
  • Heavy or frequent menstrual periods

Symptoms Of High Thyroid (Hyperthyroidism) Levels

  • Weight loss
  • Irritability
  • Anxiety
  • Difficulty sleeping
  • Enlarged thyroid gland or a goiter
  • Heart rate
  • Irregular menstrual periods
  • Menopause
  • Muscle weakness
  • Tremors
  • Palpitations
  • Vision problems
  • Eye irritation
  • Sweating
  • Nervousness

Symptoms Of Thyroid Nodules

  • Dysphagia (Narrowing of the esophagus which is caused by the tumor pressing on it)
  • Difficulty swallowing
  • Hoarseness
  • Compression of vocal cords
  • Compression on the part of the lung
  • Shortness of breath

Symptoms Of Thyroid Cancer

  • Swelling in the neck (below Adam’s apple)
  • Trouble swallowing
  • Hoarseness or other voice changes
  • Neck or throat pain
  • Cough (lasting more than two weeks)
  • Fever

Diagnosis For Thyroid Disease

Diagnosis For Thyroid Disease

Source: verywell

Thyroid disease is one of the most common endocrine disorders in the United States. There are different types of thyroid diseases, and each one can be treated differently. The diagnosis process includes:

  • Physical exam
  • Blood tests
  • Imaging tests

i. Physical Exam

A physical exam will help identify any signs of thyroid disease, such as a goiter or nodules in the neck area. This is a simple, painless test where the healthcare provider will feel your neck for any thyroid growth or enlargements.

ii. Blood Tests

Blood tests will analyze TSH levels and measure hormone levels such as thyroxine (T4) and triiodothyronine (T3).

You can have the following tests done to check your thyroid levels:

  • Thyroid-stimulating hormone (TSH)

This is the first test your provider will do to ensure your thyroid levels balance. It is produced in the pituitary gland and regulates the balance of thyroid hormones – including T4 and T3 – in the bloodstream. 

The thyroid gland also produces thyroxine (T4) and triiodothyronine (T3), so doctors may also measure these to understand better what’s going on. Signs that your thyroid may not be functioning properly are if your TSH levels fall below 0.40 mIU/mL or exceed 4.50 mIU/mL. (milli-international units per liter of blood).

  • T4

Thyroxine blood tests diagnose and monitor thyroid disorders, with hypothyroidism being shown by low T4 levels and hyperthyroidism showing high T4 levels. The normal range is 5.0-11.0 ug/dL (micrograms per deciliter of blood).

  • FT4

Free T4 (or free thyroxine) is a method of measuring T4 that eliminates the effect of proteins that bind T4 and make accurate measurements difficult. The normal FT4 range for an adult should be 0.9-1,7 ng/dL (nanograms per deciliter of blood)

  • T3

Thyroid hormone tests, like T3 tests, test for hyperthyroidism. They are often used to diagnose and manage people with this condition, as low T3 levels can be detected in a hypothyroid person. The normal T3 range is between 100 and 200 ng/dL. (nanograms per deciliter of blood).

  • FT3

The T3 resin uptake assay, also known as a Free T3 test, measures the amount of free T3 circulating in our body. FT3 levels can be checked by collecting a blood sample and running it through the slot-blot assay. The normal range for FT3 is 2.30 – 4.10 pg/mL (picograms per milliliter of blood).

Additional blood tests might include:

  • Thyroid Antibodies

Many physicians will administer a blood test to diagnose an autoimmune thyroid condition. Common thyroid antibody tests include:

  • Microsomal antibodies (also known as thyroid peroxidase antibodies or TPO antibodies)
  • Thyroglobulin antibodies (also known as TG antibodies)
  • Thyroid receptor antibodies (includes thyroid-stimulating immunoglobulins [TSI] and thyroid blocking immunoglobulins [TBI]).
  • Calcitonin

This test is used to diagnose rare forms of thyroid cancer, c-cell hyperplasia, and medullary thyroid cancer.

  • Thyroglobulin

This test is the first step in diagnosing a possible case of thyroiditis. It is also administered when a patient has been diagnosed with thyroid cancer to monitor treatment progress.

iii. Imaging Tests

Imaging tests like a thyroid scan, MRI, or ultrasound can be used to examine the thyroid gland for enlargement or nodules that may indicate cancerous cells.

  • Thyroid Scan

A thyroid scan allows your provider to look at your thyroid to check for increased size, shape, or growths (nodules).

  • Ultrasound

You may think of ultrasounds related to pregnancy, but they are used to diagnose many different issues within your body. Ultrasound is a diagnostic strategy that transmits high-frequency sound waves inaudible to the human ear via body tissues. The echoes are recorded and transformed into video or photographic images. Unlike X-rays, ultrasounds do not use radiation.

Treatment For Thyroid Disease

Hyperthyroidism is when the thyroid gland produces too much of the hormone thyroxine. Hypothyroidism is when the thyroid gland does not produce enough of this hormone.

Treatment For Thyroid Disease

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Treatment For Hyperthyroidism And Hypothyroidism

  • Patients with hyperthyroidism may be treated with anti-thyroid drugs and radioactive iodine therapy.
  • Patients with hypothyroidism may be treated with thyroid hormone replacement therapy and medication to stimulate the thyroid gland.
  • Patients with hypothyroidism may undergo thyroid surgery.

Treatment For Grave’s Disease

  • Patients with Grave’s disease may be treated with anti-thyroid drugs. 
  • Patients with Grave’s disease may undergo surgery to remove or reduce the size of the thyroid gland. 
  • Patients with Grave’s disease may also be treated with radioactive iodine therapy. 
  • Patients with Grave’s disease negative for thyroglobulin may be given thyroid hormone replacement therapy and medication to stimulate the thyroid gland. 

Treatment For Radioactive Iodine Therapy

  • Radioactive iodine is usually combined with other treatments, such as anti-thyroid drugs, surgery, and thyroid hormone replacement therapy. 
  • Radioactive iodine has a limited number of uses and is not used in all cases of Grave’s disease. 
  • The radioactive iodine therapy treatment is recommended for patients with Grave’s disease who are negative for thyroglobulin. 
  • Patients who are positive for thyroglobulin should not be given radioactive iodine therapy. 

Treatment for Thyroid Hormone Replacement Therapy

  • Patients with Grave’s disease may need to take thyroid hormone replacement therapy, which is given in pill form.
  • Thyroid hormone replacement therapy is given in pill form, injection, or implant.
  • Thyroid hormone replacement therapy is usually needed to control the symptoms of Grave’s disease, but it may not be able to stop all the symptoms.
  • Radioactive iodine may be given before or after thyroid hormone replacement therapy for those who do not have enough response to the treatment.
  • Thyroid hormones are typically given at a low dosage for a few weeks and then increased gradually to find the lowest dose that works.

Conclusion & Take Away

The thyroid gland is the most important in the endocrine system. It produces hormones that regulate metabolism, growth, and body temperature. Thyroid disease is a major health problem in the United States, with about 20 million people diagnosed. If you are one of those people, make sure to avoid thyroid disease by following these steps:

  • Do a self-exam once a month.
  • Stay active and healthy.
  • Get enough sleep at night.
  • Don’t eat too much bread or cow’s milk.
  • Limit sodium intake
  • Quit smoking

The thyroid gland affects every organ and system in the body. So, it is not uncommon for people with thyroid disease to have other health problems. It is important to keep an eye on your thyroid health. 

You can do a self-exam. It can help you identify any problems early on, which may help you avoid the development of thyroid disease. You can also have an annual physical exam with your doctor, so they can test your thyroid function and diagnose any potential problems.

Thyroid Self-Exam

Thyroid Self-Exam

Source: verywell

To do this exam, you need to place your fingers on either side of your Adam’s apple and then slide them down until they meet at the bottom of your neck. You should feel for any lumps or bumps.