What is an overactive thyroid?
Your thyroid is a small gland that’s shaped like a butterfly and is found at the front of your neck just below the larynx. When your thyroid is overactive, it produces excess levels of the two thyroid hormones, thyroxine (T4) and/or triiodothyronine (T3).
If you have an overactive thyroid, you may develop symptoms like weight loss, diarrhoea, anxiety or eye problems.
What are the symptoms of an overactive thyroid?
The symptoms of an overactive thyroid can be very generalised and difficult to differentiate from other conditions. Some common symptoms include:
Poor heat tolerance and profuse sweating
Anxiety, insomnia or being irritable
Loss of libido (sex drive)
Shorter or missed periods in women
As well as the above symptoms, look out for these physical signs of an overactive thyroid:
Swelling in your neck
What causes an overactive thyroid?
There are a number of conditions that can result in your thyroid producing excessive amounts of hormone. The most common include:
Grave’s disease – an autoimmune condition
Thyroid nodules – lumps containing thyroid tissue can develop on the thyroid gland and produce thyroid hormones
Thyroiditis – inflammation of the thyroid
Medication – iodine-containing medicines such as amiodarone
Less common causes of an overactive thyroid include thyroid cancer, a pituitary adenoma or atypical pregnancies (such as multiple pregnancies).
An overactive thyroid in pregnancy
Pregnancy can sometimes be a trigger for the production of excess thyroid hormones. It’s important that this is controlled to prevent the risk of preeclampsia, miscarriage, premature labour and birth and low birthweight.
Hyperthyroidism in pregnancy will be managed by a specialist as treatment can be complicated.
How to test for an overactive thyroid
You should speak to a GP if you think you have symptoms of an overactive thyroid. Your GP will ask about the symptoms and request a blood test to look at your thyroid function (TFT) if needed.
These examples below may mean you have or are at risk of developing hypothyroidism.
Low TSH and high T4 and/or T3 – could mean you have an overactive thyroid
Low TSH but normal T4 and T3 – may mean you are at risk of developing an overactive thyroid in the future. This is often referred to as ‘subclinical hyperthyroidism’.
Treatments for hyperthyroidism
The options for managing hyperthyroidism include:
Medications – carbimazole or propylthiouracil are used to reduce the hormone levels and beta blockers can help with symptoms
Radioactive iodine therapy – a form of radiotherapy that can help prevent excess production of hormones
Surgery – sometimes surgical removal of the thyroid gland is recommended
Typically, if your hyperthyroidism is treated then you can live a relatively normal life. But if left untreated, complications such as thyroid eye disease can develop.
If you think you’re experiencing symptoms of an overactive thyroid it is important you see a doctor.
- Reviewed by:
- Dr Alessio Platania, Lead GP at Livi
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