Some of the most common symptoms of an overactive thyroid, also known as hyperthyroidism, include thyroid enlargement, anxiety, nervousness, hair changes and difficulty sleeping, according to WebMD. Symptoms often mimic other illnesses, and people with mild forms of the condition may not notice any symptoms.
Thyroid enlargement, or goiter, occurs in the majority of patients with a hyperactive thyroid, causing a lump at the front of the neck, as stated by WebMD. While a doctor may need to feel the neck to detect a small lump, larger lumps may be visible. Patients with hyperthyroidism may be irritable and experience loose bowel movements. Double vision is sometimes present, and patients with Grave's disease may have bulging or protruding eyes. Hair can become thin or brittle with noticeable hair loss.
Women may notice less frequent menstrual periods or lighter bleeding, and older adults are more likely to experience an irregular heartbeat, according to WebMD. Sufferers can also experience a rapid heartbeat, which often exceeds 100 beats per minute. Other possible overactive thyroid symptoms include sweating, shaky hands, unexplained weight loss and thinning of the skin. Individuals who experience symptoms of hyperthyroidism should make an immediate appointment with a health care professional to receive proper diagnosis and treatment options.