Overactive Thyroid / Thyrotoxicosis

Overactive Thyroid / Thyrotoxicosis

An overactive thyroid gland is one where there is overproduction of thyroid hormones (called T3 & T4) in association with a reduced level of Thyroid-Stimulating-Hormone (TSH) from the pituitary gland.

When this is detected on blood tests without symptoms, it is called “sub-clinical”.

Symptoms of overactivity include lethargy, weight loss, increased heart rate, tremor, feeling hot, diarrhoea and hair-loss.

Overproduction of thyroid hormone may be due to overproduction by the whole gland (such as in the case of Grave’s disease, thyrotoxicosis, toxic multinodular goitre) or by part of the gland called a solitary toxic nodule.

Having a thyroid technetium scan can show if the overproduction is from the whole gland (diffuse) or part of the gland.

Blood tests may help determine causes such as Grave’s disease or thyroiditis.

Treatment depends on the cause but there are generally three options: medications, radio-iodine ablation and surgery.

  • Medications – used for up to 12 months.
  • Radio-iodine ablation – using a tablet of radioiodine to destroy the overactive gland cells. Radiation is carried by iodine which gets taken up by the gland.
  • Surgery Removing half or all of the thyroid gland. Indicated for a toxic thyroid nodule, a multi-nodular goitre or Grave’s disease that has not responded to medications or where radio-iodine is contra-indicated (cannot be used).