You're restless and nervous. You feel hungry all the time, but no matter how much you eat, you keep losing weight. You can't sleep or concentrate, and you feel hot and sweaty. If symptoms like these are putting you on edge, the problem may be an overactive thyroid gland, or hyperthyroidism.
This little butterfly-shaped structure in your neck is your thyroid gland. It's job is to release the hormones that help control your body's energy levels, a process known as metabolism. When you have hyperthyroidism, that little gland goes into overdrive, releasing too much of its hormones. Having too much thyroid hormone is like putting your body in fast forward, everything speeds up. That's why you feel shaky, hungry, and your heart feels like it's pounding.
So, what causes hyperthyroidism?
You can develop an overactive thyroid because you've gotten too much iodine, an element the thyroid uses to make its hormones. Or, you might have a growth on your thyroid that's causing the excess hormone production. But many people with hyperthyroidism have an autoimmune disorder called Graves disease, which also makes their eyes bulge out.
During an exam, your doctor may notice that your thyroid is larger than normal, and that you have high blood pressure, tremors, or a fast heart rate. These can all be signs of hypothyroidism. You'll probably have a blood test to check the levels of your thyroid hormones.
If you do have an overactive thyroid, you may need to take medicine to slow down the gland and its hormone production. Or, your doctor may suggest having surgery to remove some or all of the thyroid, or taking radioactive iodine to destroy it. If you have surgery or radioactive iodine treatment, you'll probably need to take thyroid hormones for the rest of your life to replace the ones your body can no longer make.
You can't prevent hyperthyroidism, but once you have it, it's usually pretty easy to treat. With the right treatment you can finally be free from its symptoms.
While you're being treated, watch out for an emergency condition called thyroid crisis, or thyroid storm, which can set in if you've been under a lot of stress or have an infection. If you have a fever, fast and unsteady heartbeat, or you feel less alert than usual, call your emergency services number or go to the ER right away.
Review Date: 2/19/2016
Reviewed By: Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.