Graves' disease. Graves' disease is the most common cause of overactive thyroid. It can run in families and can occur at any age, although it is most common in women aged 20-40 years old. You are more likely to develop Graves' disease if you smoke. Graves' disease is an autoimmune condition.
Full Removal. If your doctor removes your entire thyroid, your body will begin to exhibit symptoms similar to hypothyroidism, due to the lack of thyroid hormones in your body. These symptoms may include fatigue, elevated cholesterol levels, uncontrollable weight gain, muscle weakness and depression.
A goiter may require no treatment, especially if it is small and thyroid hormone levels are normal. However, if your thyroid hormone levels are affected--either too high or too low-- you will need treatment. Treatment involves getting the thyroid hormone levels back to normal, usually with medication. When the medication takes effect, the thyroid may begin to return to its normal size. However, a large nodular goiter with a lot of internal scar tissue will not shrink with treatment. If the goiter is uncomfortable, causes overproduction of thyroid hormone unresponsive to medications, or becomes cancerous, the entire thyroid gland may have to be surgically removed.