The thyroid, a small bow-tie-shaped gland located near the Apple's apple, can become overactive, which means it produces too much thyroid hormone. This can lead to a number of complications, most of which are reversible with proper treatment, reports MayoClinic.com. These complications tend to occur if a person's thyroid is overactive for a long time. Inadequate or improper treatment also leads to complications.
Impact on Bones
People with an overactive thyroid are at significant risk for brittle bones, reports Medical News Today. This is because an overactive thyroid interferes with the body's ability to take calcium into the bones. Being aware of this complication is particularly significant for older women, who are known to have a higher incidence of overactive thyroid than men and who also may be at risk for osteoporosis.
Heart Complications
Overactive thyroid can lead to several heart complications, including fast heartbeat, a heart rhythm disorder and congestive heart failure, which is when the heart fails to pump enough blood to fulfill the body's needs, reports the National Institute of Medicine. The risk for congestive heart failure is higher in older patients.
Careful monitoring can forestall this complication, which are generally reversible with treatment, explains Medical News Today.
Thyrotoxic Crisis
Rarely, complications from an overactive thyroid constitute a medical emergency. This is the case with a thyrotoxic crisis, also called a thyrotoxic storm, a sudden onset of severe symptoms leading to fever and extremely rapid pulse. Delirium or a coma can result, reports "Hyperthyroidism."
Immediate medical care should be obtained for people experiencing a thyroid storm.
Graves' Dermopathy
Another rare complication that occurs in people with overactive thyroid develop Graves' dermopathy, red or swollen skin that typically appears on the shins and top of the feet, according to Thyroid.org. This happens to people diagnosed with Graves' disease, a common type of overactive thyroid in which the immune system attacks the gland by mistake.
Eye Problems
Ulcers on the cornea and restriction in eye movements are also rare complications in people with Graves' disease, reports MayoClinic.com. Less than 1 percent of people with Graves' disease develop an eye inflammation that is severe enough to cause permanent damage, reports Thyroid.org.
Treatment-Associated Complications
On occasion, complications can develop from medicine used to treat overactive thyroid, reports Medical News Today. Antithyroid drugs, which prevent the thyroid gland from making too much thyroid hormone, can cause liver damage, which can be fatal. The risk is higher with propylthiouracil; thus, doctors use this drug only for people who cannot take methimazole, another antithyroid medication.
People taking radioactive iodine may develop eye problems; however, this effect is typically mild and temporary.
