Introduction

An overactive thyroid, also known as hyperthyroidism, is where the thyroid gland produces too much of the thyroid hormones. The thyroid is found at the front of the neck. It produces hormones that affect things such as your heart rate and body temperature. Extra levels ofthesehormones can cause unpleasant and potentially serious problems thatmay require treatment. An overactive thyroidcan affect anyone, but it's about 10 times more common in women than men and it typically startsbetween 20 and 40 years of age. This page covers: Symptoms When to see your GP Treatments Causes Further problems Symptoms of an overactive thyroid An overactive thyroid can cause a wide range of symptoms, including: nervousness, anxiety and irritability mood swings Insomnia persistent tiredness and weakness sensitivity to heat swelling in your neck from an enlarged thyroid gland (goitre) an irregular and/orunusually fast heart rate (palpitations) twitching or trembling weight loss You'll normally see an endocrinologist (specialist in hormone conditions) to discuss which is best for you. . Causes of an overactive thyroid There are a number of reasons why the thyroid can become overactive. These include: Graves' disease where the body's immune system mistakenly attacks and damages the thyroid lumps (nodules) on the thyroid this results in extra thyroid tissue, whichcan mean extra thyroid hormones are produced certain medications such asamiodarone, a medication for an irregular heartbeat (arrhythmia) About three in every four cases arebecause ofGraves' disease. . Further problems An overactive thyroid, particularly if it's not treated or well controlled, can sometimes lead to further problems. These include: eye problems such as eye irritation, double vision or bulging eyes pregnancy complicationssuch as pre-eclampsia , premature birth or miscarriage a thyroid storm a sudden and life-threatening flare-up of symptoms .