An overactive thyroid, (or thyrotoxicosis) similar to an underactive thyroid, also affects about 1 in 50 women in a lifetime. While it can affect men too, it's about 10 times less common. Further, while it can occur in younger people too, an overactive thyroid is far more common as you get older.
Your thyroid gland, located at the base of your neck (about the same position, shape and size as a bow tie) produces hormones called thyroxine (T4) and T3. It also stores these hormones, releasing them when they're needed.
You may feel restless or on edge; lose weight despite eating more; have diarrhoea or shortness of breath; get palpitations or have trembly hands. Paradoxically, even though your body is ticking over more quickly than normal, you may also notice tiredness and muscle weakness. You're unlikely to develop all these symptoms, but most people have a combination, with their symptoms often developing over several weeks.
Once you've been diagnosed, you may be offered one of several treatments. These include:
- Medication called carbimazole, which reduces the amount of thyroxine your thyroid gland produces.
- Radio-iodine, which involves taking a single drink (or capsule) that contains radioactive iodine. As the iodine builds up in your thyroid gland, it destroys some of the gland, reducing the over-production of thyroxine. The dose of radiation is very low and not dangerous to you, but it's not suitable if you're pregnant or breastfeeding (or planning to have children) and you should limit close contact with babies, children or pregnant women for a few weeks after you take it.
- Surgery to remove part of your thyroid gland may be recommended if your thyroid gland is enlarged.
- Sometimes these treatments – or the underlying condition that caused an overactive thyroid – lead you to develop an underactive thyroid. In this case, you'll be offered replacement treatment with thyroxine tablets for life.
Top tips for travel
Having an overactive thyroid shouldn't stop you enjoying a holiday, but there are several factors you need to take into account:
- Once you've been diagnosed and are on treatment, it's important to keep an eye out for recurrence of any of the symptoms of overactive thyroid gland. This could indicate that your treatment is not keeping your symptoms under control. A 'thyroid storm' or thyrotoxic crisis is a rare complication of an overactive thyroid. If you start to develop severe symptoms such as those above, or start feeling acutely unwell, seek medical help.
- If you're taking regular tablets, make sure you order your prescription well in advance. Take enough with you to last the whole trip, with some extra tablets in case your return is delayed or you mislay part of your supply.
- Take a copy of your repeat prescription with you, and ideally a doctor's letter explaining the medication you're taking. This can be useful at airport security or if you need to get more medication while you're away in case of emergency.
- Carry your medicine with you in your hand luggage, and ideally split it between you and a travelling companion just in case one bag goes astray.
- Many airports have radiation detectors. If you've had radioactive iodine treatment, this can trigger a detector for weeks or even months after you've taken it. Take a letter from your doctor explaining the treatment you've had.
- If you've had radioactive iodine treatment, avoid travelling for at least 4 weeks afterwards (and until your doctor tells you it's safe). You mustn't risk being in close contact with babies, children or pregnant women – and remember, in the early stages of pregnancy you may not know if someone is pregnant.
- Overactive thyroid can make you prone to travel sickness. Factor this into your plans and ask your doctor or pharmacist about travel sickness medication to take with you in case.
- In rare cases, carbimazole tablets can cause serious blood disorders which affect your body's ability to fight off infection. If you develop any infection like sort throat or mouth ulcers; have a fever; feel unusually tired or generally unwell; or notice abnormal bruising or bleeding, seek urgent medical help.
- In the early stages after an overactive thyroid gland is diagnosed, you'll need regular blood tests. Check with your doctor before booking any trips, in case you need monitoring during the time you're planning to be away.
- Even if you're travelling to Europe and have a valid EHIC or GHIC, it's essential to take out the correct travel insurance. Always declare your condition to your travel insurance providers and look for a specialist provider who will cover your condition.