Hyperthyroidism, or overactive thyroid, occurs when your thyroid gland produces excessive amounts of thyroid hormones. This accelerates many of your body’s functions.
Common Causes:
Graves’ disease (an autoimmune condition) is the most common cause. Other causes include thyroid nodules that produce excess hormone, inflammation of the thyroid (thyroiditis), and excessive iodine intake or certain medications containing iodine.
Symptoms:
Excess thyroid hormone causes rapid or irregular heartbeat, unexplained weight loss despite increased appetite, increased sweating and heat intolerance, nervousness, anxiety, or irritability, trembling hands, difficulty sleeping, muscle weakness, frequent bowel movements, lighter or missed periods, and bulging eyes (in Graves’ disease). Some people experience ‘thyroid storm,’ a rare but life-threatening sudden worsening of symptoms.
Diagnosis and Treatment:
Blood tests show low TSH and high T4/T3 levels. Treatment options include anti-thyroid medications to reduce hormone production, radioactive iodine to destroy thyroid tissue, or surgery to remove part or all of the thyroid. Beta-blockers may be used short-term to manage symptoms like rapid heartbeat.

