The thyroid gland, located in the front of the neck, secretes hormones that control how energy is processed in the cells of the body. According to the Mayo Clinic, hyperactive thyroid occurs when the gland produces too much of the thyroid hormone thyroxine. This condition is called hyperthyroidism. When there is too much thyroxine present, the body's metabolism speeds up, causing symptoms. A hyperactive thyroid can be due to Graves' Disease, an inflammation called thyroiditis or having one or more hot spots on the thyroid called nodules.
Fatigue and Muscle Weakness
Symptoms of a hyperactive thyroid come on slowly, according to the American Thyroid Association. One of the first noticeable symptoms can be fatigue. As the metabolism speeds up, the cells of the body have to work harder. This costs the body some of its reserve energy, resulting in lethargy and a lack of energy and motivation. When fatigue is not relieved by enough sleep and good nutrition, it should be evaluated by a medical professional. Hyperthyroidism can cause the muscles to become weakened, particularly the muscles of the thighs and upper arms.
Increased Appetite and Weight Loss
Despite having an increased appetite and getting plenty to eat, people with an overactive thyroid will lose weight, according to the University of Maryland Medical Center. The increase in the levels of the thyroid hormones act to speed up metabolism, causing an overall loss in weight which is gradual at first, but becomes more pronounced over time. Any amount of unexplained weight loss should be reported to a medical professional.
Tremors, Anxiety and Irritability
Hyperthyroidism can cause tremors, or unintentional shaking motions, especially in the hands and fingers, according to the Mayo Clinic. Increased feelings of anxiety, including anxiety attacks, are also possible. People with an overactive thyroid can also be highly irritable and nervous.
Rapid Heartbeat and High Blood Pressure
According to MedlinePlus, an overactive thyroid can also produce some heart symptoms, such a rapid heartbeat and high blood pressure. The heart can feel like it is pounding or thudding with palpitations or racing with a condition called tachycardia. Heart symptoms are some of the more serious effects of hyperthyroidism.
Other Systemic Symptoms
In women, there can be a marked decrease or complete absence of their menstrual cycle, according to MedlinePlus. There can be a noticeable increase in the frequency of bowel movements with an overactive thyroid but rarely diarrhea. Other symptoms include intolerance for heat, hair loss, insomnia, increased sweating and flushed skin.
Toxic Nodular Goiter
A toxic nodular goiter is an enlarged thyroid gland that becomes prominent and noticeably visible as a palpable swelling in the front of the neck. According to MedlinePlus, the goiter contains small, non-cancerous growths called nodules that produce too much thyroid hormone. It is seen most often in women over 60 years of age.
Graves' Ophthamology
Graves' ophthalmology is associated with hyperthyroidism. It affects the eyes and is hallmarked by markedly protruding eyeballs, redness and tearing. According to the American Thyroid Association, Graves' disease is the most common cause of an overactive thyroid gland, responsible for 70 percent of hyperthyroidism cases. With Graves', the entire thyroid is enlarged due to antibodies that attack the thyroid, causing it to produce an excess amount of thyroid hormone. Graves' is hereditary, and thus it runs in families.
