What is goiter?
Goiter is a condition in which the thyroid gland grows larger. The thyroid gland is a small, butterfly-shaped gland located in the neck, below the Adam's apple.
The thyroid gland produces the hormones thyroxine (also called T4) and triiodothyronine (also called T3). (Most of the T4 is changed to T3 outside of the thyroid.) These hormones play a role in certain bodily functions, including body temperature, mood and excitability, pulse rate, digestion and others.
Symptoms and Causes
What causes goiter?
Goiters have different causes, depending on their type.
- Simple goiters develop when the thyroid gland does not make enough hormones to meet the body's needs. The thyroid gland tries to make up for this shortage by growing larger.
- Endemic goiters occur in people in certain parts of the world who do not get enough iodine in their diet (iodine is necessary to make thyroid hormone). For instance, a lack of iodine in the diet is still a common problem in parts of central Asia and central Africa. Because iodine is added to table salt in the United States and other countries, this type of goiter usually does not occur in these countries.
- Sporadic goiters, in most cases, have no known cause. In some cases, certain drugs can cause this type of goiter. For example, the drug lithium, which is used to treat certain mental health conditions, as well as other medical conditions, can cause this type of goiter.
Other risk factors for goiter include the following:
- Hereditary (inherited from family)
- Female gender
- Age over 40
Other diseases and conditions can also cause a goiter. These include:
- Graves' disease. Graves' disease is an autoimmune disease (your body's immune system mistakenly attacks your healthy body). In this case, the immune system attacks the thyroid gland and the thyroid grows larger.
- Hashimoto's disease. This is another autoimmune disease. In this case, the disease causes inflammation (swelling) of the thyroid gland. This causes it to produce fewer thyroid hormones, resulting in a goiter. This type of goiter usually gets better on its own over time.
- Nodular goiter. In this condition, growths called nodules occur on one or both sides of the thyroid gland, causing it to grow larger.
- Thyroid cancer. Cancer of the thyroid gland often enlarges the thyroid.
- Pregnancy. Human chorionic gonadotropin, a hormone that a woman produces during pregnancy, can cause the thyroid to grow.
- Thyroiditis. Inflammation of the thyroid gland itself can cause the thyroid gland to grow. This can happen after the person has an illness caused by a virus, or after a woman gives birth.
- Exposure to radiation. A person who has had medical radiation treatments to the head and neck (but not diagnostic procedures, such as a CT scan) has a greater risk of developing goiter.
What are the symptoms of goiter?
The main symptoms of goiter include:
- A swelling in the front of the neck, just below the Adam's apple
- A feeling of tightness in the throat area
- Hoarseness (scratchy voice)
- Neck vein swelling
- Dizziness when the arms are raised above the head
Other, less common symptoms include:
- Difficulty breathing (shortness of breath)
- Wheezing (due to squeezing of the windpipe)
- Difficulty swallowing (due to squeezing of the esophagus, or “food tube”)
Some people who have a goiter may also have hyperthyroidism, or overactive thyroid. Symptoms of hyperthyroidism can include:
- An increased resting pulse rate
- Rapid heartbeat
- Diarrhea, nausea, vomiting
- Sweating without exercise or increased room temperature
Some people with goiter may also have hypothyroidism, or underactive thyroid. Symptoms of hypothyroidism can include:
- Fatigue (feeling tired)
- Dry skin
- Weight gain
- Menstrual irregularities
Diagnosis and Tests
How is goiter diagnosed?
Several tests can be used to diagnose and evaluate goiter, including the following:
- Physical exam: Your doctor may be able to tell if the thyroid gland has grown by feeling the neck area for nodules and signs of tenderness.
- Hormone test: This blood test measures thyroid hormone levels, which tell if the thyroid is working properly.
- Antibody test: This blood test looks for certain antibodies that are produced in some forms of goiter. An antibody is a protein made by white blood cells. Antibodies help defend against invaders (for example, viruses) that cause disease or infection in the body.
- Ultrasound of the thyroid: Ultrasound is a procedure that sends high-frequency sound waves through body tissues. The echoes are recorded and transformed into video or photos. Ultrasound of the thyroid reveals the gland's size and finds nodules.
- Thyroid scan: This imaging test provides information on the size and function of the gland. In this test, a small amount of radioactive material is injected into a vein to produce an image of the thyroid on a computer screen. This test is not ordered very often, since it is only useful in certain circumstances.
- CT scan or MRI (magnetic resonance imaging) of the thyroid: If the goiter is very large or spreads into the chest, a CT scan or MRI is used to measure the size and spread of the goiter.
Management and Treatment
How is goiter treated?
Treatment for goiter depends on how large the thyroid has grown, symptoms, and what caused it. Treatments include:
- No treatment/"watchful waiting." If the goiter is small and is not bothering you, your doctor may decide that it doesn’t need to be treated. However, the goiter will be closely watched for any changes.
- Medications. Levothyroxine (Levothroid®, Synthroid®) is a thyroid hormone replacement therapy. It is prescribed if the cause of the goiter is an underactive thyroid (hypothyroidism). Other medications are prescribed if the cause of the goiter is an overactive thyroid (hyperthyroidism). These drugs include methimazole (Tapazole®) and propylthiouracil. The doctor might prescribe aspirin or a corticosteroid medication if goiter is caused by inflammation.
- Radioactive iodine treatment. This treatment, used in cases of an overactive thyroid gland, involves taking radioactive iodine orally. The iodine goes to the thyroid gland and kills thyroid cells, which shrinks the gland. After radioactive iodine treatment, the patient usually has to take thyroid hormone replacement therapy for the rest of his or her life.
- Biopsy. A biopsy is the removal of a sample of tissue or cells to be studied in a laboratory. A biopsy may be needed if there are large nodules in the thyroid gland. A biopsy is taken to rule out cancer.
- Surgery. Surgery is performed to remove all or part of the thyroid gland. Surgery may be needed if the goiter is large and causes problems with breathing and swallowing. Surgery is also sometimes used to remove nodules. Surgery must be done if cancer is present. Depending on the amount of thyroid gland removed, the patient may need to take thyroid hormone replacement therapy for the rest of his or her life.