If the thyroid overproduces or underproduces hormones, it can cause hyperthyroidism or hypothyroidism. Other thyroid problems include nodules, goiters, and thyroiditis, or inflammation.

Thyroid disorders are common and can affect the body in a wide range of ways.

This article looks at the different types of thyroid disorders, what causes them, their symptoms, and how doctors diagnose and treat them.

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Hypothyroidism is when a person’s thyroid does not produce enough thyroid hormone. Not having enough thyroid hormone can slow down a person’s metabolism and lead to a range of symptoms, which may include:

A person may also develop a goiter, or enlargement of the thyroid gland. This condition occurs when the gland tries to compensate for the lack of thyroid hormone.

Causes

The potential causes of hypothyroidism include:

Hypothyroidism is more prevalent in females than in males.

Treatment

The main treatment for hypothyroidism is taking levothyroxine, which is a thyroid hormone replacement.

When iodine deficiency is the only cause of hypothyroidism, a doctor may suggest getting more iodine, with or without levothyroxine. However, if iodine deficiency is not the only cause, iodine could make things worse. In the United States, iodine deficiency is rare.

Similarly, if a medication is the cause, there may be ways to adjust the dose or try an alternative. People should discuss this with a doctor first, though.

Certain brands and strengths of medication for hypothyroidism (underactive thyroid) have been recalled. This is due to the medication having less active drug (levothyroxine) than it is supposed to.

Call your pharmacist to find out if your medication has been recalled. Do not stop taking the medication unless advised to do so by a healthcare professional.

In locations where iodine intake is usually adequate, the most common cause of the disorder is Hashimoto thyroiditis. This condition occurs when a person’s immune system attacks their thyroid gland. The gland then becomes inflamed, and hormone production falls.

Causes

The exact cause of Hashimoto thyroiditis is unclear, but heredity may play a role. If a person has close family members with the condition, their risk of developing it can be greater.

Having another autoimmune disorder, such as rheumatoid arthritis, type 1 diabetes, or lupus, also increases the risk of Hashimoto thyroiditis.

Treatment

Treatment for Hashimoto thyroiditis is similar to that of hypothyroidism. It usually involves taking levothyroxine to replace the lost thyroid hormones.

However, people with this condition may also need to avoid iodine, as they may be sensitive to its effects. A doctor may recommend avoiding iodine in supplements and in foods that contain a lot of it, such as seaweed.

Hyperthyroidism is when a person has too much thyroid hormone in their body. This can speed up their metabolic processes, causing symptoms such as:

  • fatigue and muscle weakness
  • rapid or irregular heartbeat
  • tremors in the hands
  • problems sleeping
  • nervousness
  • irritability
  • frequent bowel movements
  • unintended weight loss
  • a light menstrual flow or fewer periods

Causes

Some of the most common causes of hyperthyroidism are:

  • Graves’ disease: In Graves’ disease, the immune system creates antibodies that signal the thyroid gland to grow and produce significantly more thyroid hormone than the body needs.
  • Multinodular goiter: This condition results from hormone-producing nodules in the thyroid gland becoming enlarged and releasing excess thyroid hormone.
  • Toxic adenoma: Adenomas are growths that can occur on the thyroid. Benign and inactive adenomas do not always cause problems, but active or “toxic” adenomas produce thyroid hormone.

A person may also experience an increase in thyroid hormone levels due to:

  • thyroid inflammation
  • taking too much thyroid hormone replacement
  • other drugs, such as tyrosine kinase inhibitors
  • getting too much iodine
  • cancer

Treatment

Treatments for hyperthyroidism may include:

  • Antithyroid drugs: These drugs can stop the thyroid from making so much thyroid hormone.
  • Radioactive iodine tablets: When a person ingests these tablets, thyroid cells absorb the iodine. This treatment then destroys them, and the gland’s hormone overproduction stops.
  • Surgery: A surgeon may remove a part or all of a person’s thyroid.

Depending on the cause, doctors may also need to address other conditions affecting the thyroid, such as cancer. Alternatively, if iodine or a medication is the only cause, they may recommend reducing the intake or changing to another drug.

If a person takes radioactive iodine or undergoes surgery, their thyroid may no longer produce enough hormones, and they may develop hypothyroidism. In this instance, they would then require thyroid hormone replacement treatment.

Thyroid nodules are lumps on a person’s thyroid and can appear alone or in groups.

Thyroid nodules are common. Around 50% of people over 60 years old have a thyroid nodule. However, the vast majority of thyroid nodules are harmless.

It is not clear why people develop thyroid nodules. Thyroid nodules do not typically cause symptoms, although in some cases, they may cause hyperthyroidism.

A doctor will be able to feel thyroid nodules on a person’s neck during an examination. If they discover nodules, they may check for hyperthyroidism or hypothyroidism.

During diagnosis, doctors may also perform an ultrasound or a fine-needle biopsy to check for cancer.

If there are any signs of cancer or possible cancer risk in the future, a doctor will recommend removing the nodules. Depending on the type of cells found in a biopsy, and the risk of the nodule being cancer, a doctor may remove part or all of the gland.

A goiter occurs when the thyroid gland swells. It can occur due to:

  • hypothyroidism
  • hyperthyroidism
  • thyroiditis
  • pituitary gland tumors

For some, the only symptom of a goiter is the swelling in the neck. For others, it may be part of a group of symptoms that are the result of the underlying cause.

Those with very large goiters may also experience:

  • tightness in the neck
  • hoarse voice
  • coughing or wheezing
  • difficulty speaking or swallowing

Doctors treat goiters by addressing their cause. For example, if it is hypothyroidism, this may mean taking levothyroxine.

Doctors use blood tests to diagnose hypothyroidism and hyperthyroidism. These will assess levels of thyroid-stimulating hormone (TSH) and thyroxine in a person’s blood.

The body releases TSH to signal the thyroid gland to release thyroid hormones. When the body senses low thyroid hormone levels, it releases more TSH. A high level of TSH typically indicates hypothyroidism.

Thyroxine is a hormone released by the thyroid gland. Low levels of thyroxine in the blood indicate hypothyroidism, whereas high thyroxine and low TSH may indicate hyperthyroidism.

A doctor may also look for physical signs of a thyroid disorder, such as:

  • an enlarged thyroid
  • tremors in the fingers
  • a rapid pulse

Once a doctor is able to make a diagnosis, they may perform additional tests to look for the underlying cause. For example, they may perform medical imaging to see if there are any nodules or growths.

The thyroid gland is responsible for producing hormones that regulate the body’s metabolism.

There are many different thyroid disorders, but doctors typically categorize them into those that make the thyroid produce too much or too little of these hormones.

Hyperthyroidism occurs when the thyroid gland produces too much thyroid hormone. This speeds up a person’s metabolism and can result in an increased heart rate, high blood pressure, and fatigue.

Conversely, hypothyroidism is when the thyroid gland produces too little hormone. This lowers the body’s metabolism and can lead to tiredness, feelings of cold, and constipation.

If a person is concerned that they may have a thyroid disorder, they should speak with a doctor about testing.