The thyroid gland, found in the neck, produces hormones that control the body's growth and metabolism. Not only do these hormones affect heart rate and body temperature, as well as other processes, they also help to convert food into energy, keeping the body functioning.
An overactive thyroid, or hyperthyroidism, is a condition where there is too much thyroid hormone in the body. These excess levels can speed up the metabolism, giving rise to a range of symptoms. We take a look at the causes, symptoms and treatments of the condition.
According to the NHS, the most common cause of overactive thyroid is Graves' disease. Most common in women between the ages of 20 and 40, this autoimmune condition causes the immune system to attack the thyroid gland, leading to overproduction of the hormones. It can run in the family, and occur at any age, and you are also more likely to develop the condition if you smoke.
Thyroid nodules are another common cause. These usually benign lumps contain abnormal tissue, which affects the production of the thyroid hormones. Iodine, either from in the food that you eat or as a supplement, can also cause an overactive thyroid, while amiodarone - a medication used to treat an irregular heartbeat, can also trigger hyperthyroidism because of the iodine it contains.
In rare cases, an overactive thyroid may develop as a result of follicular thyroid cancer.
The symptoms of hyperthyroidism are many, and can vary greatly from person to person. Hyperactivity, mood swings, fatigue and insomnia could point to a problem, while very infrequent or light periods, the need to pass stools or urinate more often, and diarrhoea are also common symptoms.
Unexplained weight loss, often despite an increased appetite, muscle weakness, infertility and a lack of libido could also signal an overactive thyroid.
Sufferers may also notice a swelling on the neck, where the thyroid gland has become enlarged, an irregular or fast heart rate, and experience trembling. Redness on the palms of the hands, nails that are loose in the nail bed, raised itchy swellings on the skin and patchy hair loss are other symptoms that may occur.
Though it is unlikely an overactive thyroid will cause the whole range of symptoms, and they may well point to an altogether different problem, it is always worth a visit to your GP if you experience the above.
If you are diagnosed with hyperthyroidism, your GP will refer you to an endocrinologist, who specialises in hormonal conditions.
One of the most commonly used treatments is thionamides, a medication that prevents the thyroid gland from producing excess levels of thyroid hormones. This type of medication usually requires between four and eight weeks to show an improvement, and some sufferers may need to continue taking the drug for a long period, though a specialist will often gradually reduce the medication over time.
Radioiodine treatment is another regularly-prescribed form of treatment, which shrinks the thyroid gland, thereby reducing the amount of hormone it is able to produce. Given as either a drink or capsule, the dose of radioactivity is very low and not harmful, but it is nevertheless unsuitable for pregnant or breast-feeding women, and those who suffer with the eye problems often associated with Graves' disease. Women are advised not to get pregnant for at least six months after finishing the treatment, while men should avoid fathering a child for four months after having radioiodine.
Throughout treatment, either with thionamides or radioiodine, beta-blockers may be prescribed to help relieve some of the symptoms such as nausea, fatigue and insomnia.
Surgery to remove all or part of the thyroid gland is sometimes recommended if the gland is very swollen or if other treatments are not suitable.
Do you suffer with an overactive thyroid? What advice would you give others with the condition? Leave your comments below...