context: If your thyroid is swollen, you may have a condition called thyroiditis. It primarily affects women from early adulthood to middle age, although anyone can get it. The thyroid is the butterfly-shaped gland located in the front of your throat, just below your Adam's apple. It controls your metabolism by producing hormones that influence how fast or slow your heart, brain, and other parts of your body work. There are different types of thyroiditis, but they all have something in common. All cause inflammation and swelling of your thyroid. They can make it produce too many or not enough hormones. Too many can make you feel jittery and possibly make your heart race. Too few and you may feel tired and depressed. About 20 million Americans have a form of thyroid disease. Like the others, thyroiditis can be a serious illness. Treatment will depend on the type you have and any symptoms that it may be causing. Treatment can range from daily medication to surgery. Here's what you should know about this disease. There are many things that can make your thyroid swell. You may have gotten an infection from a virus or bacteria. You may be taking a drug like lithium or interferon. Or you may have problems with your immune system. One form of thyroiditis shows up after childbirth. Pregnancy has a major impact on the thyroid in general. These are the most common causes: Hashimoto's disease. This is the most common type of thyroiditis. Your immune system starts attacking your thyroid and gradually weakens the gland until it can't produce enough thyroid hormones. Subacute thyroiditis. This type is often triggered by an infection. With subacute thyroiditis, there is generally a predictable pattern of how the thyroid functions. First, the thyroid and neck area are painful. Then the thyroid produces too much hormone, also called hyperthyroidism. Then there is a phase of normal function, followed by a time where the thyroid produces too little thyroid hormone. This is called hypothyroidism. After about 12 - 18 months, thyroid function returns to normal. Post-partum thyroiditis. This type begins within a year after childbirth, particularly in women with a history of thyroid issues. With treatment, the thyroid usually recovers within 18 months. Silent thyroiditis. As the name suggests, there are no symptoms with this type. It's similar to post-partum thyroiditis and recovery usually takes up to 18 months. It starts with a phase too much hormone production, followed by a longer period of the thyroid producing too little. There are some common symptoms that include fatigue, swelling at the base of your neck, and perhaps some pain in the front of your throat However, other symptoms will vary, depending on whether your thyroid is underactive (hypothyroidism) or overactive (hyperthyroidism). Symptoms of hypothyroidism may include: Fatigue Depression Weight gain Dry skin Constipation Muscle aches Intolerance to cold Symptoms of hyperthyroidism may include: Anxiety and irritability Weight loss Insomnia Heart palpitations Muscle weakness Intolerance of heat Blood test. Thyroid hormones circulate in the blood and their levels can help your doctor figure out what specific kind of thyroiditis you may have. Radioactive iodine uptake test ( RAIU). Since iodine collects in your thyroid gland, you're given a sample of radioactive iodine as a pill or liquid. Over the next 24 hours, your doctor will check at several points to see how much iodine your thyroid has absorbed. Thyroid scan. In this test, you're injected with radioactive iodine. You then will be asked to lie face up on a table with your head bent back, exposing your neck. Your doctor then uses a device to take images of your thyroid. These tests are usually performed in the doctor's office on an outpatient basis. It varies depending on the type of thyroiditis you have. Hypothyroidism is generally treated with synthetic versions of thyroid hormone. These are taken as pills. As your metabolism returns to normal, your doctor may adjust the dosage. The treatment of hyperthyroidism depends on the type of inflammation and also on any symptoms that you may be having. Beta blockers are often used to treat symptoms like a fast heart rate and palpitations. Anti-thyroid medicines can be used to lower the amount of hormones that the thyroid is making. Sometimes, your doctor may prescribe a form of radioactive iodine to shrink the thyroid and reduce any symptoms. If you have thyroid pain, your doctor may recommend treating it with nothing more than aspirin or ibuprofen. Severe pain may be addressed in other ways. Although rare, surgery will be needed if other treatments aren't tolerated or working.