What is Hypothyroidism?

The thyroid gland is a butterfly-shaped gland situated just below your Adam’s apple in the neck. It produces the thyroid hormones, triiodothyronine (T3) and thyroxine (T4). The thyroid gland produces more T4 but T3 is the most potent hormone. T3 is also generated by conversion of T4 after secretion from the thyroid gland. These two hormones are important in metabolism and the metabolic rate. Excess thyroid hormone results in a high metabolic rate increased heart rate and weight loss whereas deficient thyroid hormone results in a low metabolic rate, low body temperature, slow pulse and weight gain.

What causes Hypothyroidism?

Hypothyroidism can be a result of dysfunction of the thyroid gland (primary hypothyroidism) or less commonly a result of failure of the pituitary (secondary hypopituitarism), which stimulates the thyroid through the hormone TSH (Thyroid Stimulating Hormone). The most common cause of primary hypothyroidism is autoimmune destruction of the thyroid gland. This is where the body’s own immune system attacks the thyroid gland and prevents it producing thyroid hormone. Less commonly the thyroid may be removed surgically because of thyroid lumps or tumours resulting in long term hypothyroidism. Secondary hypothyroidism during pituitary disease is most commonly caused by a benign pituitary tumour or surgery for the tumour. Rarely, hypothyroidism can be congenital (inherited) and this can be both primary and secondary.

How common is Hypothyroidism?

Hypothyroidism can occur at any age but is more frequent in the elderly and it is estimated that up to 5% of people over 60 years are hypothyroid.

What are the symptoms of Hypothyroidism?

The signs and symptoms of hypothyroidism are relatively non-specific but include: tiredness, weight gain, cold intolerance, constipation, joint and muscle pain, dry skin, thin and brittle hair or fingernails. In younger patients it may be a cause of infertility.

What is the current treatment?

The majority of patients are currently treated with thyroxine (T4) tablets. These are taken on a daily basis. However some patients may take T3 with T4 or T3 alone.

Further support for people affected by Hypothyroidism

Thyroid Foundation logo

The British Thyroid Foundation works closely with patients and medical professionals to produce reliable information and practical support for people affected by all thyroid disorders.

Visit the British Thyroid Foundation for further information.

Diurnal Group plc (Company Number: 09846650) is registered in England & Wales. Registered office: Cardiff Medicentre, Heath Park, Cardiff CF14 4UJ, UK.