What is hyperthyroidism?
Thyroid is a gland which sits at the base of neck. It produces a hormone called thyroid hormone. Hyperthyroidism or overactive thyroid is a condition where thyroid gland produces excess hormone.
Cause
Common causes of hyperthyroidism are Graves disease (autoimmune disease), multinodular goitre and thyroiditis.
Symptoms
Thyroid hormone controls metabolism. Increase in thyroid hormone results in anxiety, irritability, hyperactivity, fatigue, difficulty to sleep, hair loss, palpitations, tremors, weight loss, intolerant to warm weather, thyroid eye disease, diarrhoea and infrequent menstruation.
Investigations
Thyroid hormone test can show raised levels of free thyroxine and low levels of TSH.
Treatment
There are three types of treatment.
a) Antithyroid medications such carbimazole and Propylthiouracil can help control hormone levels. However, dose of medications need regular review as hormone levels can fluctuate.
b) RadioIodine 131 is a type of internal radiotherapy which destroys the thyroid tissue and renders it underactive. It is a definite management. It can be given in mild thyroid eye disease, but caution in moderate or severe eye disease. Additionally, patient needs to keep distance of one metre from children for 2 weeks. Patient will need levothyroxine for lifelong.
c) Thyroid surgery. It is definite treatment. Risks of damage to recurrent laryngeal nerve and removal of parathyroid gland are in range of 0.3% to 5%. Patient will need levothyroxine for lifelong.
Untreated Hyperthyroidism
If overactive thyroid is not treated, it results in irregular heart beat called atrial fibrillation, which can cause stroke. Additionally weak bones (osteoporosis) and memory loss (dementia) has been reported.
