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Q&As

These Q&As first appeared in the TEDct Newsletter. The answers were provided by our specialist medical consultants.

Answers provided by: Miss G G W Adams FRCS(Ed) FRCOphth (Consultant Ophthalmic Surgeon, Moorfields Eye Hospital), Colin Dayan MA MRCP PhD (Consultant Lecturer in Medicine, University of Bristol) and John Sloper, Strabismus and Paediatric Service, Moorfields Eye Hospital

Whilst undertaking a course of radiotherapy should I stay away from children?

No, there is not risk of contamination.

Is it true that having radioactive iodine treatment can make an existing TED condition worse?

Yes, it’s true that radioactive iodine treatment for Graves’ disease can made Thyroid Eye Disease worse, particularly if you are a smoker. This can sometimes be prevented with a short course of oral steroid tablets after radioiodine, however, most clinicians would avoid radioiodine if you have active TED and prefer alternative treatment such as antithyroid drug or a removal of the thyroid.

Will having the thyroid removed exacerbate an existing TED condition?

Thyroid surgery has not been shown to be associated with a worsening of Thyroid Eye Disease.

What are the long-term side effects of Propylthiouracil?

There is no evidence that the long-term effects of being on propylthiouracil to control an overactive thyroid are any different from the side-effects seen occasionally in the short-term.

Side-effects that have been reported include a rash, joint pains, fever, jaundice from liver damage and an effect on the bone marrow. This last is the most dangerous. You become aware of it by developing sores in the mouth for no obvious reason. If this happens, or you suspect it, you must stop the Propylthiouracil THE SAME DAY and visit your doctor or a casualty department THE SAME DAY to undergo a blood check to see if the bone marrow has stopped making a particular type of white blood cell (neutrophils or granulocytes). Take your tablets along to show the doctor as some doctors may not be familiar with this side-effect of these drugs. The side-effect is known as agranulocytosis. While the neutrophil count is low, you are at risk from severe infections developing suddenly. If you stop taking the tablet straight away, the bone marrow usually recovers completely. However, this leads to problems in treating overactive thyroid since if you have had agranulocytosis you should never take Propylthiouracil again.

There is also a small but an increasing risk after several years of treatment of another rare condition affecting skin, joints and possibly kidneys, called vasculitis., These effects are very rare, and if they do occur, most side-effects are seen in the first 3 months of treatment if they are going to occur at all. Recently, it has been highlighted that propylthiouracil can rarely cause severe liver damage. If you develop jaundice, you must stop the drug and see your doctor the SAME DAY.

Doctors on the whole are unhappy about patients continuing for many years on Carbimazole/Propylthiouracil not because new “late” side-effects develop but because patients remain at risk of the usual side-effects as long as they stay on the drug. Radioiodine and surgery however both remain options.

What are the long-term side effects of Carbimazole?

There is no evidence that the long-term effects of being on Carbimazole to control an overactive thyroid are any different from the side-effects seen occasionally in the short-term.

Side-effects that have been reported include a rash, joint pains, fever, jaundice from liver damage and an effect on the bone marrow. This problem is the most dangerous and is indicated by the development of sores in the mouth for no obvious reason. If this happens, or you suspect it, you must stop taking the Carbimazole THE SAME DAY and visit your doctor or a casualty department THE SAME DAY for a blood check to see if the bone marrow has stopped making a particular type of white blood cell called neutrophils or granulocytes. Take your tablets along to show the doctor as some doctors may not be familiar with this side-effect of these drugs. The side-effect is known as agranulocytosis. While the neutrophil count is low, you are at risk from severe infections developing suddenly. . If you stop taking the tablet straight away, the bone marrow usually recovers completely. However, this leads to problems in treating the overactive thyroid since if you have had agranulocytosis you should not take Carbimazole again. Radioiodine and surgery however both remain options.

Doctors on the whole are unhappy about patients continuing for many years on carbimazole/propylthiouracil not because new “late” side-effects develop but because patients remain at risk of the usual side-effects as long as they stay on the drug.

Will my retracting eyelid return to normal over period of time?

If it is of short duration, it may return to normal following treatment of thyroid overactivity and Thyroid Eye Disease. However, if TED is burnt out (inactive) and thyroid function has been stable for many years then it is unlikely that the eyelid retraction will resolve spontaneously. This can be rectified with surgery.

Does drinking alcohol worsen eye function for those with TED?

There is no evidence that drinking alcohol makes eye function worse when suffering from Thyroid Eye Disease.

Does taking melatonin affect the thyroid function?

Melatonin is a hormone released by the brain during sleep. People take melatonin for a variety of reasons including improving the length and quality of sleep and to readjust their sleep after jet lag. In animals, including rats, hamsters and turtles, taking melatonin reduces thyroid hormone levels, probably by an effect on the pituitary gland, which controls the thyroid. There have not been many studies in humans, but in one there was a rise and in another there was no change in TSH or thyroid hormone levels. So the answer is, melatonin could affect thyroid hormone levels, but we don't yet know how often thyroid function changes are seen or why.

Does smoking worsen eye function for those with TED?

Yes, there is strong evidence that smoking whilst suffering from Thyroid Eye Disease will make the eyes worse. Moreover, treatments for TED are less effective if you are a smoker.

Can TED cause short-sightedness?

No, the eye changes in Thyroid Eye Disease are different from those that cause short-sightedness.

Is blepharitis common with Thyroid Eye Disease.

Blepharitis is a very common eye problem altogether and is often compared to dandruff of the eyelids. Mild forms are usually treated by cleaning the eyelid margins once or twice a day with a cotton bud and cooled boiled water together with a mild shampoo such as a Baby Shampoo. More severe cases need ophthalmological attention and may need antibiotic ointment or other treatment.

Is it OK to take seaweed or the ingredient E407 (a natural extract of seaweed present in some toothpastes) with TED.

Seaweed, kelp tablets and seafood contain large amounts of iodine, which is absorbed by the thyroid gland. There is evidence that in people who take large amounts of iodine, thyroid activity is more difficult to control and is less responsive to radioactive iodine. On the other hand, too little iodine can cause an underactive thyroid gland and goitre. However, there is no evidence to suggest a direct effect on Thyroid Eye Disease. In general, it is best to opt for moderation. It is not advisable for people to take iodine/seaweed supplements when suffering from thyroid disease, but would doubt if the small amounts in toothpaste make much difference, especially if they are not swallowed.

Is Thyroid Eye Disease hereditary?

There is little doubt that many thyroid diseases run in families. If your parents or siblings are affected with Graves' disease (autoimmune thyroid overactivity) or Hashimoto's disease (autoimmune damage to the thyroid), then there is an increased risk that you will have a thyroid disturbance, although it may be so mild that it causes you little trouble. With regard to Thyroid Eye Disease however, a study looked at 114 people with severe TED and only 3 of the 114 had other affected family members. Although Thyroid Eye Disease is more common in males than would be expected since thyroid disease is relatively uncommon in men, it does appear overall that genes play a smaller part in deciding who gets severe TED than other factors, such as smoking.