The thyroid is a small, butterfly-shaped gland located at the base of the 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, and the thyroid gland itself produces the hormones that regulate your body’s metabolism.
In hyperthyroidism, the thyroid gland is overactive. Hyperthyroidism can affect anyone, but it’s around 10 times more common in women than men.
Graves’ disease is the most common cause of hyperthyroidism, affecting about 70% of people with an overactive thyroid. Nodules on the thyroid — a condition called toxic nodular goitre or multinodular goitre — can also cause the gland to overproduce its hormones.
Excessive thyroid hormone production leads to symptoms such as:
- racing heart
- increased sweating
- trouble sleeping
- thin skin
- brittle hair and nails
- muscle weakness
- weight loss
- bulging eyes (in Graves’ disease)
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.
Another test a doctor may perform involves giving you radioactive iodine by mouth or as an injection, and then measuring how much iodine your thyroid gland takes up. This method is sometimes used because 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 usually aim to destroy the thyroid gland or block it from producing its hormones. Antithyroid drugs are also sometimes used to prevent the thyroid from producing its hormones. In serious cases, surgery may be performed to remove your thyroid gland.
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 disease, surgery to remove the thyroid gland, or damage from radiation treatment. Most cases of hypothyroidism are mild.
Too little thyroid hormone production leads to symptoms such as:
- dry skin
- increased sensitivity to cold
- memory problems
- weight gain
- slow heart rate
Hypothyroidism diagnosis and treatment
Diagnosis usually involves a blood test 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 stimulate the thyroid gland to make its hormone.
The main treatment for hypothyroidism is to take prescription thyroid hormone pills. It’s important to get the dose right, because taking too much thyroid hormone can cause symptoms of hyperthyroidism.
Hashimoto’s disease is also known as chronic lymphocytic thyroiditis. 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 disease 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 can include:
- mild weight gain
- dry skin
- dry, thinning hair
- pale, puffy face
- heavy and irregular menstruation
- intolerance to cold
- enlarged thyroid, or goitre
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 disease 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 disease. 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 UK, affecting around 3 in every 4 people with an overactive thyroid gland.
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 common risk factors include stress and smoking.
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 may 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 the 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 for more severe cases, or those who can’t tolerate antithyroid drugs or radioactive iodine)
Successful hyperthyroidism treatment usually results in hypothyroidism, meaning hormone-replacement medication will need to be taken from that point forward. Graves’ disease can sometimes lead to heart problems and brittle bones if it’s left untreated.
Goitre is a noncancerous enlargement of the thyroid gland, causing a visible lump in the neck. The most common cause of goitre worldwide is iodine deficiency in the diet.
Goitre can affect anyone at any age, especially in areas of the world where foods rich in iodine are in short supply. However, goitres 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 goitre isn’t severe. The goitre may cause one or more of the following symptoms if it grows large enough, depending on the size:
- swelling or tightness in the neck
- difficulties breathing or swallowing
- coughing or wheezing
- hoarseness of voice
Goitre diagnosis and treatment
Your doctor will feel your neck area and have you swallow during a 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 goitre. An ultrasound of the thyroid can check for swelling or nodules.
Goitre is usually treated only when it becomes severe enough to cause symptoms. You can take small doses of iodine if goitre 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 goitre is often a symptom of hyperthyroidism.
Goitres are often associated with highly treatable thyroid disorders, such as Graves’ disease. Although goitres 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. The causes aren’t always known but can include iodine deficiency and Hashimoto’s disease. The nodules can be solid or filled with fluid.
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 goitre.
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:
- high pulse rate
- increased appetite
- weight loss
- clammy skin
On the other hand, symptoms will be similar to hypothyroidism if the nodules are associated with Hashimoto’s disease. These include:
- 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.
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 fairly rare — according to the National Cancer Institute, thyroid cancer affects less than 4% of the population. The treatment your doctor recommends will vary depending on the type of tumour, but removing the thyroid through surgery is often 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.