What is hyperthyroidism?

Hyperthyroidism is the increased production of thyroxine hormones by the thyroid gland.


Causes and Risk Factors

Under the control of thyroid-stimulating hormone (TSH) from the pituitary, the thyroid gland produces thyroid hormones thyroxine (T4) and triiodothyronine (T3).  Thyroid hormones affect metabolism, heat production as well as growth and development.

Disorder of the thyroid, like all endocrine glands, can lead to the following:

  • Goitre – gland swelling
  • Hyperthyroidism – increased production of thyroid hormones
  • Hypothyroidism – reduced thyroid function
  • The most common cause of hyperthyroidism is Graves’ disease (autoimmune hyperthyroidism). Hyperthyroidism can also arise from functioning nodules within the thyroid. A blood test with raised thyroid hormones and suppressed TSH confirms the diagnosis of hyperthyroidism.



  • Weight Loss
  • Palpitations
  • Excessive Sweating
  • Anxiety
  • Breathlessness
  • Leg Swelling



Anti-thyroid drugs for 12 to 18 months, depending on condition

  • Surgery
  • Radioactive iodine (RAI)

RAI may be best choice in those with heart disease


Gleneagles Hospital Penang
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