Thyroid

• The thyroid gland, shaped like a 2-inch butterfly, is located right in the front of your neck, just above the hollow part. The two "wings" of the gland wrap around your trachea (windpipe). There are several thyroid hormones, but the main one is thyroxin, often abbreviated as T4. The thyroid hormones affect on just about every part of your body, because they work to increase the activity of cells, and thus, metabolism. Thyroid problems occur more often in women.
  
  

Hyperthyroidism

• With the disorder hyperthyroidism, the thyroid gland produces too much thyroxin. Because thyroxin speeds up cellular processes in your body, the symptoms of hyperthyroidism are all things that happen too fast or too much: weight loss, heartbeat, sweating, edginess. The most common underlying cause for hyperthyroidism is Grave's disease, an autoimmune disease. In these types of diseases, the body attacks its own tissues as if they were invaders from outside; in Grave's disease, the immune system attacks the thyroid. Hyperthyroidism can also be caused by growths, known as nodules, on the gland. Treatment for hyperthyroidism includes beta-blockers and antithyroid medicines, such as radioactive iodine, one dose of which destroys part of the thyroid gland. Surgery is also an option, but is considered the last resort.
  
  

Hypothyroidism

• The opposite condition of hyperthyroidism is an underactive thyroid, or hypothyroidism. The symptoms for this disorder are related to your body's metabolism slowing down, including fatigue, weakness and depression. The most common cause of hypothyroidism is damage to the gland by inflammation or an illness such as Hashimoto's thyroiditis. But this disorder also can be the result of treatments administered for another condition, such as radiation therapy for cancer. The simplest treatment for hypothyroidism is to take thyroid hormone. After being diagnosed, most people must take it for the rest of their lives.
  
  

Cancer

• Many people have nodules on their thyroids that are not cancerous. In fact, thyroid cancer is a relatively rare form of cancer with an excellent survival rate, because most cases are caught early. Swelling in the neck or unexplained hoarseness should be checked immediately. The best treatment for thyroid cancer is the removal of the part of the thyroid containing the abnormal cells. This type of cancer can return, so thyroid cancer patients should be monitored closely for life.
  
  

Other Diseases

• Benign thyroid nodules are very common; most don't cause any symptoms. Swelling of the thyroid gland is called a goiter, which can be harmless or the symptom of an underlying condition. Chronic inflammation of the thyroid is called thyroiditis, and treatment varies, depending on the form and severity. In short, any swelling or pain in the thyroid gland should be checked out by a doctor immediately.