The thyroid gland is located at the front of the neck. Like other endocrine organs, the hormones it secretes has a wide-ranging effect across the whole body. There are four main ways thyroid disease may cause symptoms:
• Overactivity: There is excess circulating thyroid hormone due to overproduction or leakage from the gland. Typical symptoms include palpitations, shaking, excess sweatiness, mood swings, increased appetite, and weight loss.
• Underactivity: With this condition the thyroid gland is unable to produce sufficient thyroid hormone to maintain body function. Patients may notice increased sensitivity to cold weather, lethargy, weight gain, hair loss, and constipation.
• Thyroid nodules: Nodules are lumps within the thyroid gland. This is a very common occurrence, and most nodules do not cause problems unless they become large or start to produce excess thyroid hormone. In rare cases they may develop into cancer.
• Thyroid cancer: This is the most common cancer of the endocrine system. Thyroid cancers are usually treated with a combination of surgery, radioactive iodine, and thyroid hormone suppression.