Thyroid Disorders

Medically Reviewed on 4/29/2022

What are thyroid disorders?

Picture of Thyroid Gland
Thyroid problems manifest with different symptoms depending on the underlying cause.

Thyroid disorders are conditions that affect the thyroid gland, a butterfly-shaped gland in the front of the neck. The thyroid has an important role in regulating numerous metabolic processes throughout the body. Different types of thyroid disorders affect either its structure or function.

The thyroid gland is located below Adam's apple wrapped around the trachea (windpipe). A thin area of tissue in the gland's middle, known as the isthmus, joins the two thyroid lobes on each side. The thyroid uses iodine to produce vital hormones. Thyroxine, also known as T4, is the primary hormone produced by the gland. After delivery via the bloodstream to the body's tissues, a small portion of the T4 released from the gland is converted to triiodothyronine (T3), which is the most active hormone.

The function of the thyroid gland is regulated by a feedback mechanism involving the brain. When thyroid hormone levels are low, the hypothalamus in the brain produces a hormone known as thyrotropin-releasing hormone (TRH) that causes the pituitary gland (located at the base of the brain) to release thyroid-stimulating hormone (TSH). TSH stimulates the thyroid gland to release more T4.

Since the thyroid gland is controlled by the pituitary gland and hypothalamus, disorders of these tissues can also affect thyroid function and cause thyroid problems.

What are the specific kinds of thyroid disorders?

There are specific kinds of thyroid disorders that include:


Hypothyroidism results from the thyroid gland producing an insufficient amount of thyroid hormone. It can develop from problems within the thyroid gland, pituitary gland, or hypothalamus.

Symptoms of hypothyroidism can include:

Some common causes of hypothyroidism include:

  • Hashimoto's thyroiditis (an autoimmune condition that causes inflammation of the thyroid gland)
  • Thyroid hormone resistance
  • Other types of thyroiditis (inflammation of the thyroid), such as acute thyroiditis and postpartum thyroiditis


Hyperthyroidism describes excessive production of thyroid hormone, a less common condition than hypothyroidism. Symptoms of hypothyroidism usually relate to increased metabolism. In mild cases, there may not be apparent symptoms.

Symptoms and signs of hyperthyroidism can include:

  • Tremor
  • Nervousness
  • Fast heart rate
  • Fatigue
  • Intolerance for heat
  • Increase in bowel movements
  • Increased sweating
  • Concentration problems
  • Unintentional weight loss

Some of the most common causes of hyperthyroidism include:

  • Graves' disease
  • Toxic multinodular goiter
  • Thyroid nodules that overexpress thyroid hormone (known as "hot" nodules)
  • Excessive iodine consumption


Thyroid Disorders See a medical illustration of the thyroid plus our entire medical gallery of human anatomy and physiology See Images


A goiter simply describes enlargement of the thyroid gland, regardless of cause. A goiter is not a specific disease per se. A goiter may be associated with hypothyroidism, hyperthyroidism, or normal thyroid function.

Thyroid nodules

Nodules are lumps or abnormal masses within the thyroid. Nodules can be caused by benign cysts, benign tumors, or, less commonly, by cancers of the thyroid. Nodules may be single or multiple and can vary in size. If nodules are excessively large, they may cause symptoms related to compression of nearby structures.

Thyroid cancer

Thyroid cancer is far more common among adult women than men or youth. About 2/3 of cases occur in people under age 55. There are different kinds of thyroid cancer, depending upon the specific cell type within the thyroid that has become cancerous. Most cases of thyroid cancer have a good prognosis and high survival rates, especially when diagnosed in its early stages.

How are thyroid disorders diagnosed?

In addition to thorough medical history and physical exams, specialized tests are used to diagnose thyroid disorders.

  • Blood tests are typically done to measure levels of thyroid hormones and TSH. Blood tests to identify antibodies against thyroid tissue may also be ordered by your doctors, such as titers of anti-thyroglobulin, anti-thyroperoxidase, or TSH receptor-stimulating antibodies.
  • Imaging tests are commonly used when thyroid nodules or enlargements are present. Ultrasound can visualize the consistency of the tissue within the gland and can often reveal cysts or calcifications. Ultrasound examination cannot distinguish a benign from a malignant process.
  • Thyroid scans using radioactive iodine are often performed to evaluate the function of thyroid nodules. The thyroid is the only location in the body that takes up iodine, so when radioactively labeled iodine is given, it is taken up by the thyroid gland. An imaging test typically shows the uptake of radioactive iodine by normal thyroid tissue. Areas or nodules that are producing excess hormone (referred to as hyperfunctioning) will show increased uptake of iodine. These are referred to as "hot" nodules or areas. By contrast, so-called "cold" nodules represent areas with decreased iodine uptake. "Cold" nodules do not produce excess hormones and can sometimes represent cancer.
  • Fine needle aspiration and biopsy are techniques that remove a sample of cells or tissue from the thyroid gland for examination and diagnosis by a pathologist, who is a physician trained in the diagnosis of conditions based on tissue samples. Fine needle aspiration (FNA) uses a long, thin needle to withdraw a sample of cells from the thyroid. FNA can be performed in the doctor's office. Sometimes, ultrasound imaging is used to guide the FNA procedure. A biopsy is the surgical sampling of tissue.

What is the treatment for thyroid disorders?

Thyroid disorders can be treated by medications or, in some cases, surgery. Treatment will depend on the particular disease of the thyroid.

Thyroid medications

Medications can be given to replace the missing thyroid hormone in hypothyroidism. Synthetic thyroid hormone is given in pill form by mouth. When hyperthyroidism is present, medications can be used to decrease the production of thyroid hormone or prevent its release from the gland.

Other medications can be given to help manage the symptoms of hyperthyroidism, such as increased heart rate. If hyperthyroidism is not controlled with medications, radioactive ablation can be performed. Ablation involves giving doses of iodine labeled with radioactivity that selectively destroys the thyroid tissue.

Thyroid surgery

Surgery can be used to remove a large goiter or a hyperfunctioning nodule within the gland.

Surgery is necessary when there is a possibility of thyroid cancer. If the thyroid gland is removed entirely, the individual will need to take synthetic thyroid hormone for life.

Thyroid surgery can also be used in Graves' Disease (subtotal thyroidectomy) and was the treatment of choice before RAI therapy and anti-thyroid medications. It is not used much now.

What is the outlook for thyroid disorders?

In most cases, thyroid disorders can be well managed with medical treatment and are not life-threatening. Some conditions may require surgery.

The outlook for most people with thyroid cancer is also good, although patients with thyroid cancer that has spread throughout the body have a poorer prognosis.

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What are the complications of thyroid problems?

What are the complications of hypothyroidism?

If untreated, hypothyroidism can lead to various complications, such as:

  • Goiter: The lack of thyroid hormone causes constant stimulation of the thyroid gland causing enlargement of the thyroid gland. This is called goiter. Goiter can cause cosmetic concerns and can affect breathing and swallowing.  
  • Cardiac (heart) problems: Hypothyroidism increases the risk of heart disease and causes irregular heart rate and heart failure. Hypothyroidism increases the levels of low-density lipoprotein (LDL) cholesterol, known as the “bad” cholesterol, leading to cardiovascular complications.
  • Mental health issues: Depression, slow mental function, lethargy, and poor memory can occur and may worsen over time. 
  • Peripheral neuropathy: Long-term untreated hypothyroidism can cause damage to your peripheral nerves (in the arms and legs). Patients present with pain, numbness, and tingling in affected areas.
  • Myxedema: This is a rare, life-threatening complication of long-term, untreated hypothyroidism. Its signs and symptoms include swelling of the face including the lips, eyelids, and tongue, and swelling and thickening of the skin and underlying tissues anywhere in the body having a waxy texture. Patients also have intense cold intolerance and drowsiness followed by profound lethargy and unconsciousness.
  • Infertility: Low levels of thyroid hormone can interfere with ovulation presenting with irregular periods. 
  • Birth defects: Babies born to women with untreated thyroid disease may have a higher risk of being born with birth defects. The children also have a risk of serious developmental problems.
  • Infants: Infants with untreated hypothyroidism present at birth are at risk for serious problems with both physical and mental development. 
  • Pregnant women: Untreated hypothyroidism during pregnancy increases the risk of miscarriage, premature delivery preeclampsia (high blood pressure in the last trimester of pregnancy), and birth defects in the developing baby.

What are the complications of hyperthyroidism?

If untreated, hyperthyroidism can lead to various complications, such as:

  • Cardiac (heart) complications: Cardiac complications of hyperthyroidism can be serious and life-threatening. Cardiac complications include a rapid heart rate and altered heart rhythm called atrial fibrillation which can increase the risk of stroke and heart failure.
  • Brittle bones: Untreated hyperthyroidism can lead to osteoporosis (weak, brittle bones) causing the bones to fracture easily. Increased thyroid hormones impair the body's ability to incorporate calcium into the bones.
  • Eye complications: Those with Graves' ophthalmopathy develop eye problems, including bulging, red, or swollen eyes, photophobia (sensitivity to light), blurry vision or double vision, and even loss of vision/blindness.
  • Skin complications: Those with Graves' disease develop Graves' dermopathy, which is characterized by redness and swelling of the skin, usually on the shins and feet.
  • Thyrotoxic crisis: Thyrotoxic crisis is a sudden intensification of symptoms, causing fever, palpitations, and altered mental status. This requires emergency medical attention.

What foods are bad for the thyroid?

Certain foods may interfere with the ability of the thyroid gland to process or produce thyroid hormones. These are called goitrogens.

Foods that are bad for your thyroid may include:

  • The high content of fluoride in cold drinks damages the thyroid gland like no other beverage.
  • Foods belonging to the brassica family such as broccoli, kale, cauliflower, and cabbage contain substances that may alter thyroid function. These foods, especially if eaten raw (salads), can cause T3 and T4 levels to dip.
  • Soy foods such as tofu, edamame, and soybeans contain isoflavones that act as goitrogens in your body and inhibit the production of thyroid hormones. Steer clear of soy products and select fermented soy foods to minimize the concentration of goitrogenic compounds in your diet.
  • Iodine which is essential for a healthy thyroid gland may paradoxically suppress T3 and T4 function if taken in excess. Daily consumption of iodine should not be more than 150 grams. Hence, only take iodide supplements such as kelp, nori, and seaweed under a doctor's supervision.
  • Fried foods and foods that contain saturated fats are also bad for thyroid health and function.
  • Although consuming gluten is generally not a problem for most people, it can impair nutrient absorption and trigger GI inflammation in those who have celiac disease. Unfortunately, some people with hypothyroidism, which is caused by an autoimmune disorder such as Hashimoto’s disease, are also at a high risk of being affected by celiac disease. Some people must avoid gluten completely to maintain thyroid function.
  • Caffeine dependence is detrimental to your thyroid and adrenal glands. Caffeine blocks the absorption of thyroid hormone, so you should minimize caffeine consumption as much as possible if you have hypothyroidism.
  • Excess sugar consumption wreaks havoc on the body. In addition to causing a slew of diseases, it interferes with T4 conversion which is necessary for thyroid function.
  • Alcohol can suppress the thyroid gland’s ability to produce thyroid hormones, which is why doctors advise people who have an underactive thyroid to stop drinking alcohol.

What foods can I eat to support healthy thyroid function?

Foods that support healthy thyroid function may include

  • Protein: Grass-fed meats, free-range chicken, wild-caught seafood, and beans (slow-cooked)
  • Selenium: Brazil nuts, organic liver, cold-water fish, and garlic
  • Magnesium: Dark leafy greens, almonds, pecans, and flax seeds
  • Vitamin B12: Grass-fed meats, free-range chicken and eggs, and wild-caught seafood
  • Iodine: Wild-caught seafood, seaweed, and kelp
  • Iron: Grass-fed beef, organic beef liver, spinach, and sardines
  • Zinc: Grass-fed meats, free-range chicken, wild-caught seafood, and almonds
  • Vitamin B2: Grass-fed meats, organic organ meats, almonds, and green vegetables
  • Vitamin D: Sunshine, egg yolks, organic liver, and wild-caught fish
  • Omega-3 fatty acids: Wild-caught fish, walnuts, chia, and flax seeds
  • Vitamin C: Broccoli, brussels sprouts, citrus fruits, and berries
  • Vitamin A: Free-range eggs, green vegetables, and organic liver

Can thyroid problems cause burning mouth syndrome?

Burning mouth syndrome is a severe, painful condition characterized by burning sensations in the tongue, lips, palate (roof of the mouth), gums, inside of the cheeks, and back of the mouth or throat. The feeling is often described as a scalding or tingling sensation. It is more common in women than in men and is particularly common around menopause. It may often be due to poorly functioning salivary glands. The poor function may be linked to abnormal T3 levels. Often, a diet rich in selenium and iodine is found to provide relief in some cases.


Where is the thyroid gland located? See Answer

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Medically Reviewed on 4/29/2022
American Cancer Society. Thyroid cancer.