Normal TSH levels range from 0.4 to 4.5 mU/L. TSH levels vary by age, sex, and other factors. Some experts suggest upper limit should be around 2.5 mU/L
Autoimmune disorder causing hyperthyroidism affecting nearly 1 in 100 Americans. Immune system attacks thyroid gland, producing excessive hormones. Thyroid controls body's energy use and affects nearly every organ
Hyperthyroidism affects about 1% of US population. Most common in females aged 20-50. Most common cause is Graves disease, caused by autoimmune antibodies. Other causes include toxic nodular goiter and thyroiditis
Diagnosis requires medical history, physical exam and blood tests. Physical exam checks for tremor, rapid pulse, eye changes and warm skin. Blood tests measure T-4, T-3 and TSH levels. Radioiodine scan shows thyroid gland uptake patterns. Thyroid ultrasound helps find nodules without radiation
Hyperthyroidism causes excessive thyroid hormone production and rapid metabolism. Main symptoms include rapid heart rate, weight loss, increased appetite and anxiety. Goitre may develop as thyroid gland enlargement, often due to iodine deficiency. Exophthalmos (bulging eyes) and hair loss can occur. Rare cases may cause irregular heartbeat, breathing difficulties or unconsciousness
Graves' disease is an autoimmune thyroid disorder causing hyperthyroidism. Affects about 0.5% of males and 3.0% of females. Most common cause of hyperthyroidism in US (50-80% of cases). Usually starts between ages 40-60