The thyroid is a small gland found at the base of your neck, just below your Adam’s apple. The thyroid produces two main hormones called T3 and T4. These hormones travel in your blood to all parts of your body. These thyroid hormones control the rate of many activities in your body. These include how fast you burn calories and how fast your heart beats. All of these activities together are known as your body’s metabolism. A thyroid that is working normally will produce the right amounts of hormones needed to keep your body’s metabolism working at a normal rate.
Women are more likely than men to develop thyroid disorders. Thyroid disorders include:
- Thyroid nodules
- Thyroid cancer
Some disorders cause the thyroid to produce more thyroid hormones than the body needs. This is called hyperthyroidism or overactive thyroid. The most common cause of hyperthyroidism is Graves’ disease. Graves’ disease is an autoimmune disorder, in which the body’s own defense system, called the immune system, stimulates the thyroid. This causes it to make too much of the thyroid hormones. Hyperthyroidism can also be caused by thyroid nodules that prompt excess thyroid hormones production.
Symptoms of hyperthyroidism
- Weight loss, even if you eat the same or more food
- Eating more than usual
- Rapid or irregular heartbeat or pounding of your heart
- Trouble sleeping
- Trembling in your hands and fingers
- Increased sweating
- Increased sensitivity to heat
- Muscle weakness
- More frequent bowel movements
- Less frequent menstrual periods with lighter than normal menstrual flow
- Osteoporosis, or weak, brittle bones.
Hypothyroidism is when your thyroid does not produce enough thyroid hormones. It is also called underactive thyroid. The most common cause of hypothyroidism is Hashimoto’s disease. Hashimoto’s disease is an autoimmune disease, in which the immune system mistakenly attacks the thyroid. This attack damages the thyroid resulting in reduced hormone production. Hypothyroidism also can be caused by:
- Treatment of hyperthyroidism
- Radiation treatment of certain cancers
- Thyroid removal
- In rare cases, problems with the pituitary gland can cause the thyroid to be less active.
Symptoms of hypothyroidism
- Weight gain, even though you are not eating more food
- Increased sensitivity to cold
- Muscle weakness
- Joint or muscle pain
- Fatigue (feeling very tired)
- Pale dry skin
- A puffy face
- A hoarse voice
- Excessive menstrual bleeding
- High blood levels of LDL (bad) cholesterol.
A thyroid nodule is a swelling in one section of the thyroid gland. The nodule can be solid or filled with fluid or blood; one thyroid nodule or many. Most thyroid nodules do not cause symptoms however some thyroid nodules make too much of the thyroid hormones, causing hyperthyroidism. Sometimes, nodules enlarge and cause problems with swallowing or breathing. In fewer than 10 percent of cases, thyroid nodules are cancerous.
Thyroid nodules are quite common. There is a 50 percent chance of having a thyroid nodule larger than a half inch wide.
Thyroiditis is inflammation, or swelling, of the thyroid. There are several types of thyroiditis, one of which is Hashimoto’s thyroiditis. Other types of thyroiditis include:
Like Hashimoto’s disease, postpartum thyroiditis seems to be caused by a problem with the immune system. Post-partum thyroiditis occurs in about 5 -10 percent of women. The first phase starts 1 to 4 months after giving birth. In this phase, one may get symptoms of hyperthyroidism because the damaged thyroid releases thyroid hormones out into the bloodstream. The second phase starts about 4 to 8 months after delivery. In this phase, one may get symptoms of hypothyroidism because, by this time, the thyroid has lost most of its hormones. Not everyone with postpartum thyroiditis goes through both phases. In most women who have postpartum thyroiditis, thyroid function returns to normal within 12 to 18 months after symptoms start.
Risk factors for postpartum thyroiditis include having:
- An autoimmune disease, like type 1 diabetes
- A personal history or family history of thyroid disorders
- Having had postpartum thyroiditis after a previous pregnancy
Silent or painless thyroiditis
Symptoms are the same as in postpartum thyroiditis, but they are not related to having given birth.
Symptoms are the same as in postpartum and silent thyroiditis, but the inflammation in the thyroid leads to pain in the neck, jaw, or ear. Unlike the other types of thyroiditis, subacute thyroiditis may be caused by an infection.
Most people with thyroid cancer have a thyroid nodule that is not causing any symptoms. If you have a thyroid nodule, there is a small chance it may be thyroid cancer. To tell if the nodule is cancerous, your doctor will have to do certain tests. A few people with thyroid cancer may have symptoms. If the cancer is big enough, it may cause swelling you can see in the neck. It may also cause pain or problems swallowing. Some people get a hoarse voice.
Thyroid cancer is rare compared with other types of cancer. It is more common in people who:
- Have a history of exposure of the thyroid to radiation (but not routine X-ray exposure, as in dental X-rays or mammograms)
- Have a family history of thyroid cancer
- Are older than 40 years of age
A goiter is an abnormally enlarged thyroid gland. Causes of goiter include:
- Iodine deficiency. Iodine is a mineral that your thyroid uses for making thyroid hormones. Not getting enough iodine in your food and water can cause your thyroid to get bigger. This cause of goiter is uncommon in the United States because iodine is added to table salt.
- Hashimoto’s disease
- Graves’ disease
- Thyroid nodules
- Thyroid cancer
Usually, the only symptom of a goiter is a swelling in your neck. But a very large or advanced goiter can cause a tight feeling in your throat, coughing, or problems swallowing or breathing.
Having a goiter does not always mean that your thyroid is not making the right amount of hormones. Depending on the cause of your goiter, your thyroid could be making too much, not enough, or the right amount of hormones.
Thyroid disorders diagnosis
Thyroid disorders can be hard to diagnose because their symptoms can be linked to many other health problems. The doctor will start by taking a medical history and asking if any of your family members has a history of thyroid disease.
The doctor will also give you a physical exam and check your neck for thyroid nodules. Depending on your symptoms, your doctor may also do other tests, such as:
- Level of thyroid stimulating hormone (TSH)
- Radioactive iodine uptake test
- Thyroid scan
- Thyroid fine needle biopsy
- Thyroid ultrasound