Overview
The thyroid is a small, butterfly-shaped gland located at the base of your neck just below the Adam’s apple. It’s part of an intricate network of glands called the endocrine system. The endocrine system is responsible for coordinating many of your body’s activities. The thyroid gland manufactures hormones that regulate your body’s metabolism.
Several different disorders can arise when your thyroid produces too much hormone (hyperthyroidism) or not enough (hypothyroidism).
Four common disorders of the thyroid are Hashimoto’s thyroiditis, Graves’ disease, goiter, and thyroid nodules.
In hyperthyroidism, the thyroid gland is overactive. It produces too much of its hormone. Hyperthyroidism affects about 1 percent of women. It’s less common in men.
Graves’ disease is the most common cause of hyperthyroidism, affecting about 70 percent of people with an overactive thyroid. Nodules on the thyroid — a condition called toxic nodular goiter or multinodular goiter — can also cause the gland to overproduce its hormones.
Excessive thyroid hormone production leads to symptoms such as:
Hyperthyroidism diagnosis and treatment
A blood test measures levels of thyroid hormone (thyroxine, or T4) and thyroid-stimulating hormone (TSH) in your blood. The pituitary gland releases TSH to stimulate the thyroid to produce its hormones. High thyroxine and low TSH levels indicate that your thyroid gland is overactive.
Your doctor might also give you radioactive iodine by mouth or as an injection, and then measure how much of it your thyroid gland takes up. Your thyroid takes in iodine to produce its hormones. Taking in a lot of radioactive iodine is a sign that your thyroid is overactive. The low level of radioactivity resolves quickly and isn’t dangerous for most people.
Treatments for hyperthyroidism destroy the thyroid gland or block it from producing its hormones.
- Antithyroid drugs such as methimazole (Tapazole) prevent the thyroid from producing its hormones.
- A large dose of radioactive iodine damages the thyroid gland. You take it as a pill by mouth. As your thyroid gland takes in iodine, it also pulls in the radioactive iodine, which damages the gland.
- Surgery can be performed to remove your thyroid gland.
If you have radioactive iodine treatment or surgery that destroys your thyroid gland, you will develop hypothyroidism and need to take thyroid hormone daily.
Hypothyroidism is the opposite of hyperthyroidism. The thyroid gland is underactive, and it can’t produce enough of its hormones.
Hypothyroidism is often caused by Hashimoto’s thyroiditis, surgery to remove the thyroid gland, or damage from radiation treatment. In the United States, it affects around 4.6 percent of people 12 years old and older. Most cases of hypothyroidism are mild.
Too little thyroid hormone production leads to symptoms such as:
Hypothyroidism diagnosis and treatment
Your doctor will perform blood tests to measure your TSH and thyroid hormone levels. A high TSH level and low thyroxine level could mean that your thyroid is underactive. These levels could also indicate that your pituitary gland is releasing more TSH to try to stimulate the thyroid gland to make its hormone.
The main treatment for hypothyroidism is to take thyroid hormone pills. It’s important to get the dose right, because taking too much thyroid hormone can cause symptoms of hyperthyroidism.
Hashimoto’s thyroiditis is also known as chronic lymphocytic thyroiditis. It’s the most common cause of hypothyroidism in the United States, affecting about 14 million Americans. It can occur at any age, but it’s most common in middle-aged women. The disease occurs when the body’s immune system mistakenly attacks and slowly destroys the thyroid gland and its ability to produce hormones.
Some people with mild cases of Hashimoto’s thyroiditis may have no obvious symptoms. The disease can remain stable for years, and symptoms are often subtle. They’re also not specific, which means they mimic symptoms of many other conditions. Symptoms include:
Hashimoto’s diagnosis and treatment
Testing the level of TSH is often the first step when screening for any type of thyroid disorder. Your doctor might order a blood test to check for increased levels of TSH as well as low levels of thyroid hormone (T3 or T4) if you’re experiencing some of the above symptoms. Hashimoto’s thyroiditis is an autoimmune disorder, so the blood test would also show abnormal antibodies that might be attacking the thyroid.
There’s no known cure for Hashimoto’s thyroiditis. Hormone-replacing medication is often used to raise thyroid hormone levels or lower TSH levels. It can also help relieve the symptoms of the disease. Surgery might be necessary to remove part or all of the thyroid gland in rare advanced cases of Hashimoto’s. The disease is usually detected at an early stage and remains stable for years because it progresses slowly.
Graves’ disease was named for the doctor who first described it more than 150 years ago. It’s the most common cause of hyperthyroidism in the United States, affecting about 1 in 200 people.
Graves’ is an autoimmune disorder that occurs when the body’s immune system mistakenly attacks the thyroid gland. This can cause the gland to overproduce the hormone responsible for regulating metabolism.
The disease is hereditary and may develop at any age in men or women, but it’s much more common in women ages 20 to 30, according to the Department of Health and Human Services. Other risk factors include stress, pregnancy, and smoking.
When there’s a high level of thyroid hormone in your bloodstream, your body’s systems speed up and cause symptoms that are common to hyperthyroidism. These include:
Graves’ disease diagnosis and treatment
A simple physical exam can reveal an enlarged thyroid, enlarged bulging eyes, and signs of increased metabolism, including rapid pulse and high blood pressure. Your doctor will also order blood tests to check for high levels of T4 and low levels of TSH, both of which are signs of Graves’ disease. A radioactive iodine uptake test might also be administered to measure how quickly your thyroid takes up iodine. A high uptake of iodine is consistent with Graves’ disease.
There’s no treatment to stop the immune system from attacking the thyroid gland and causing it to overproduce hormones. However, the symptoms of Graves’ disease can be controlled in several ways, often with a combination of treatments:
- beta-blockers to control rapid heart rate, anxiety, and sweating
- antithyroid medications to prevent your thyroid from producing excessive amounts of hormone
- radioactive iodine to destroy all or part of your thyroid
- surgery to remove your thyroid gland, a permanent option if you can’t tolerate antithyroid drugs or radioactive iodine
Successful hyperthyroidism treatment usually results in hypothyroidism. You’ll have to take hormone-replacement medication from that point forward. Graves’ disease can lead to heart problems and brittle bones if it’s left untreated.
Goiter is a noncancerous enlargement of the thyroid gland. The most common cause of goiter worldwide is iodine deficiency in the diet. Researchers estimate that goiter affects 200 million of the 800 million people who are iodine-deficient worldwide.
Conversely, goiter is often caused by — and a symptom of — hyperthyroidism in the United States, where iodized salt provides plenty of iodine.
Goiter can affect anyone at any age, especially in areas of the world where foods rich in iodine are in short supply. However, goiters are more common after the age of 40 and in women, who are more likely to have thyroid disorders. Other risk factors include family medical history, certain medication usage, pregnancy, and radiation exposure.
There might not be any symptoms if the goiter isn’t severe. The goiter may cause one or more of the following symptoms if it grows large enough, depending on the size:
Goiter diagnosis and treatment
Your doctor will feel your neck area and have you swallow during a routine physical exam. Blood tests will reveal the levels of thyroid hormone, TSH, and antibodies in your bloodstream. This will diagnose thyroid disorders that are often a cause of goiter. An ultrasound of the thyroid can check for swelling or nodules.
Goiter is usually treated only when it becomes severe enough to cause symptoms. You can take small doses of iodine if goiter is the result of iodine deficiency. Radioactive iodine can shrink the thyroid gland. Surgery will remove all or part of the gland. The treatments usually overlap because goiter is often a symptom of hyperthyroidism.
Goiters are often associated with highly treatable thyroid disorders, such as Graves’ disease. Although goiters aren’t usually a cause for concern, they can cause serious complications if they’re left untreated. These complications can include difficulty breathing and swallowing.
Thyroid nodules are growths that form on or in the thyroid gland. About 1 percent of men and 5 percent of women living in iodine-sufficient countries have thyroid nodules that are large enough to feel. About 50 percent of people will have nodules that are too tiny to feel.
The causes aren’t always known but can include iodine deficiency and Hashimoto’s thyroiditis. The nodules can be solid or fluid-filled.
Most are benign, but they can also be cancerous in a small percentage of cases. As with other thyroid-related problems, nodules are more common in women than men, and the risk in both sexes increases with age.
Most thyroid nodules don’t cause any symptoms. However, if they grow large enough, they can cause swelling in your neck and lead to breathing and swallowing difficulties, pain, and goiter.
Some nodules produce thyroid hormone, causing abnormally high levels in the bloodstream. When this happens, symptoms are similar to those of hyperthyroidism and can include:
On the other hand, symptoms will be similar to hypothyroidism if the nodules are associated with Hashimoto’s disease. This includes:
- fatigue
- weight gain
- hair loss
- dry skin
- cold intolerance
Thyroid nodules diagnosis and treatment
Most nodules are detected during a normal physical exam. They can also be detected during an ultrasound, CT scan, or an MRI. Once a nodule is detected, other procedures — a TSH test and a thyroid scan — can check for hyperthyroidism or hypothyroidism. A fine needle aspiration biopsy is used to take a sample of cells from the nodule and determine whether the nodule is cancerous.
Benign thyroid nodules aren’t life-threatening and usually don’t need treatment. Typically, nothing is done to remove the nodule if it doesn’t change over time. Your doctor may do another biopsy and recommend radioactive iodine to shrink the nodules if it grows.
Cancerous nodules are pretty rare — according to the National Cancer InstituteTrusted Source, thyroid cancer affects less than 4 percent of the population. The treatment your doctor recommends will vary depending on the type of tumor. Removing the thyroid through surgery is usually the treatment of choice. Radiation therapy is sometimes used with or without surgery. Chemotherapy is often required if the cancer spreads to other parts of the body.
Children can also get thyroid conditions, including:
- hypothyroidism
- hyperthyroidism
- thyroid nodules
- thyroid cancer
Sometimes children are born with a thyroid problem. In other cases, surgery, disease, or treatment for another condition causes it.
Hypothyroidism
Children can get different types of hypothyroidism:
- Congenital hypothyroidism occurs when the thyroid gland doesn’t develop properly at birth. It affects about 1 out of every 2,500 to 3,000 babies born in the United States.
- Autoimmune hypothyroidism is caused by an autoimmune disease in which the immune system attacks the thyroid gland. This type is often caused by chronic lymphocytic thyroiditis. Autoimmune hypothyroidism often appears during the teenage years, and it’s more common in girls than boys.
- Iatrogenic hypothyroidism happens in children who have their thyroid gland removed or destroyed — through surgery, for example.
Symptoms of hypothyroidism in children include:
- fatigue
- weight gain
- constipation
- intolerance to cold
- dry, thin hair
- dry skin
- slow heartbeat
- hoarse voice
- puffy face
- increased menstrual flow in young women
Hyperthyroidism
There are multiple causes of hyperthyroidism in children:
- Graves’ disease is less common in children than in adults. Graves’ disease often appears during the teenage years, and it affects more girls than boys.
- Hyperfunctioning thyroid nodules are growths on a child’s thyroid gland that produce too much thyroid hormone.
- Thyroiditis is caused by inflammation in the thyroid gland that makes thyroid hormone leak out into the bloodstream.
Symptoms of hyperthyroidism in children include:
- fast heart rate
- shaking
- bulging eyes (in children with Graves’ disease)
- restlessness and irritability
- poor sleep
- increased appetite
- weight loss
- increased bowel movements
- intolerance to heat
- goiter
Thyroid nodules
Thyroid nodules are rare in children, but when they do occur, they’re more likely to be cancerous. The main symptom of a thyroid nodule in a child is a lump in the neck.
Thyroid cancer
Thyroid cancer is the most common type of endocrine cancer in children, yet it’s still very rare. It’s diagnosed in less than 1 out of every 1 million children under age 10 each year. The incidence is slightly higher in teens, with a rate of about 15 cases per million in 15- to 19-year-olds.
Symptoms of thyroid cancer in children include:
- a lump in the neck
- swollen glands
- tight feeling in the neck
- trouble breathing or swallowing
- hoarse voice
In most cases, you can’t prevent hypothyroidism or hyperthyroidism. In developing countries, hypothyroidism is often caused by iodine deficiency. However, thanks to the addition of iodine to table salt, this deficiency is rare in the United States.
Hyperthyroidism is often caused by Graves’ disease, an autoimmune disease that isn’t preventable. You can set off an overactive thyroid by taking too much thyroid hormone. If you’re prescribed thyroid hormone, make sure to take the correct dose. In rare cases, your thyroid can become overactive if you eat too many foods that contain iodine, such as table salt, fish, and seaweed.
Though you may not be able to prevent thyroid disease, you can prevent its complications by getting diagnosed right away and following the treatment your doctor prescribes.