The thyroid is a small organ located in the front of the neck, along the windpipe, just below the larynx (Adam's Apple). The purpose of the thyroid is to absorb iodine from foods and convert it to thyroxine (T3) and triiodothyronine (T4), which are then released into the bloodstream. The thyroid hormones are responsible for controlling metabolism in every cell in the body. The pituitary gland, in the brain, controls thyroid function. When T3 and T4 levels drops, the pituitary gland releases thyroid-stimulating hormone (TSH) to tell the thyroid to produce more T3 and T4.
When the thyroid produces too much T3 and T4 on a regular basis, it is called hyperthyroidism. Often, the changes that occur in the body are gradual, so it takes some time before the person realizes there is a problem. Common symptoms include: heat intolerance, palpitations, nervousness, insomnia, fatigue, increased heart rate, trembling hands, weight loss, and hair loss. The most common cause of hyperthyroidism is Graves' Disease, which affects women 8:1 compared to men. Other less common causes of hyperthyroidism are a toxic nodule of the thyroid, thyroiditis (can occur briefly after pregnancy, will usually take care of itself), and taking too much medication to treat hypothyroidism. For hyperthyroidism not related to pregnancy-induced thyroiditis, there are several forms of treatment. Anti-thyroid medications, such as methimazole (Tapazole) and propylthiouracil (PTU), block hormone production of the thyroid. These will not cure the hyperthyroidism and it is likely the patient will remain on the medication long-term. The most common treatment for hyperthyroidism is using radioactive iodine to kill the thyroid gland. Unfortunately, this results in hypothyroidism, which I will discuss in the next section. Another treatment that results in hypothyroidism is the surgical removal of all or part of the thyroid gland.
When the thyroid does not regularly produce enough T3 and T4, it is called hypothyroidism. There are 2 major causes of hypothyroidism: inflammation of the thyroid (which damages thyroid cells) and a wide range of medical treatments, such as those mentioned above. Common symptoms of an underactive thyroid include: fatigue, weakness, weight gain/difficulty losing weight, coarse and dry hair, dry skin, hair loss, cold intolerance, muscle aches and cramps, depression, irritability, and memory loss. When untreated for a long time, a goiter may form as a result of TSH continuously being sent to the thyroid to try to get it to produce more T3 and T4. Hypothyroidism can usually be diagnosed with a simple blood test and is treated by taking a small pill every day. There are several different thyroid medications and your doctor or endocrinologist will find the best treatment for you. Some medications are levothyroxine, Synthroid, and Levoxyl. This condition does not correct itself and the pills will be taken for the rest of the patient's life.
As with any medical information you find online, you should contact your doctor for diagnosis and if you have any concerns. I have personal experience with Graves' Disease, which was treated by radioactive iodine in February 1999 and I have since dealt with hypothyroidism. If you even suspect a thyroid issue, please get to your doctor and have your thyroid checked. I promise you, if it is a thyroid issue, whether it is hyper- or hypo-, you will feel SO much better once it is being treated. For more information, check out Endocrine Web.