Our patient webinar was held as a question and answer session with paediatric endocrinologists,  Prof Tim Cheetham, Newcastle and Dr James Law, Nottingham. Many of the questions were posed by parents and carers of children with thyroid disorders. This is a shortened transcript of the patient questions answered live by our experts.

Key: TC = Tim Cheetham, JL = James Law, JP = Julia Priestley, BTF

What are your key messages to the parents of a newborn with Congenital Hypothyroidism (CHT)

Since the introduction of screening for CHT, as part of the newborn bloodspot screening programme that most babies will have in their first week of life, we can pick up the vast majority of cases. (JL)

So, one of the first key messages is that this is a treatable condition. If we get children on that medication early, they are monitored regularly and they take the treatment as prescribed, we will see normal growth patterns and normal development in the vast majority of cases. So, your children will almost always do as well as their peers without congenital hypothyroidism.

The other thing that has happened over the last 10 years or so is that the threshold on the screening tests has changed. As a consequence we are picking up milder cases in that early period. So, we can offer thyroxine treatment from an early age to children who would not necessarily be identified and treated in the past.

My 10-year old son has CHT and Attention Deficit Hyperactivity Disorder (ADHD) and struggles to focus at school; particularly when his thyroid levels are out of range. Should children with thyroid disorders be allowed additional time to take exams etc? (TC)

If it is a new diagnosis where the child’s thyroid levels are not yet fully stablised, then there is the potential for this to affect exam performance.

Equally, there are studies in adults, and in some children as well, that show if you manage to get good biochemical control you should see a similar quality of life, including academic performance and behaviours, as that seen in children without CHT.

Of course, one of the difficulties is that some of the signs and symptoms of hypothyroidism are also commonly seen in children and teenagers without thyroid disorders, such as altered attention span, headaches and tiredness. So, trying to tease out what is due to the underlying thyroid condition, due to other conditions like ADHD, or due to the way that teenagers simply feel on the day, can be really difficult.

So, I think there needs to be an open discussion with all parties (health professional, young person and parent) recognising that problems may not always be down to the thyroid disorder. (JL)

Yes, we do not have all the answers. In some situations, it is very clear that the young person’s learning may have been affected by their thyroid disorder. For example, we know Graves’ disease can make it very hard to concentrate at school due to very high levels of circulating thyroid hormones in the body. Clearly if, for example, a child has developed an overactive thyroid (hyperthyroidism), which has often been going on for quite a while before diagnosis, in the year leading up to GCSEs, it is entirely appropriate for a doctor to write a supportive letter.

If the Graves’ disease was diagnosed a while ago and biochemical control has been pretty good, then the case may be more difficult to make. (TC)

Can school performance be affected by a thyroid condition?

In young people who are profoundly hypothyroid (TSH of 150+) when they are diagnosed and then started on thyroxine, sometimes their school performance – somewhat surprisingly - goes to pot. This is because the brain has become used to periods of being relatively underactive.

We see families who feel very relieved to have received a diagnosis of hypothyroidism in  their child. Paradoxically though, on occasions, parents are not so pleased after they have started on thyroxine because of a subsequent deterioration in their school performance. This is because the human body is very good at adapting and if you have had low thyroid hormone levels for a long time, you sit at the back of the class and tend to get on with things. Then suddenly your doctor gives you this thyroxine that your body has not seen for some time and, a bit like when you become overactive, it can impact on your school performance.

So, I would say that if it is subtle thyroid dysfunction then you would not usually expect going on thyroxine to have a major impact on performance in school subjects. But if the thyroid function was profoundly abnormal then I think if you go on to thyroxine, school performance can actually deteriorate in the short term. (TC)

When a child is diagnosed with an underactive thyroid, should they be under an endocrinologist, a general paediatrician or a GP?

In my area, we generally recommend that all children with thyroid disorders are seen by a paediatrician with an interest in endocrinology. This is because thyroid hormone is so important for your growth. So, monitoring as you are going through periods of growth is important. Having someone with a specialist interest who understands the biochemical pathways behind thyroid disorders, means they can confirm whether it is likely to be autoimmune hypothyroidism (where the child is too old for it to be CHT) or other alternatives. (JL)

In the past, children with CHT used to be treated by general paediatricians in non-specialist clinics who were not always familiar with some of the potential complications. For this reason, the British Society for Paediatric Endocrinology and Diabetes (BSPED) and The British Thyroid Foundation (BTF) have highlighted the importance of children being looked after by a doctor who sees a lot of thyroid patients. (TC)

What should be measured in thyroid function tests and why?

GPs will most likely check TSH. This is secreted from the brain and controls thyroid hormone levels. For the vast majority of us, if your TSH is normal, then your T4 and T3 levels are also likely to be normal.  That is due to the relationship between them. So, if your T4 and T3 go slightly out of range slightly, your TSH will shift significantly further.

In central hypothyroidism, where there is a problem with the pituitary gland, measuring the TSH is pretty useless. In those situations, you really do have to be measuring free T4, looking ideally for a free T4 in the top half of the reference range.

In our specialist clinics, we often look at those other thyroid hormones; T3 and T4. T4 is in greater proportion in your blood but the T3 is the one that actually works in your cells.

Why is T3 not routinely checked?

Measuring blood T3 is helpful but it does not necessarily tell you what is going on at the cellular level. So, I think if your TSH is measured by your GP and that is normal, it is usually very reassuring. I would certainly always measure T4 alongside the TSH to rule out other things.

In Nottingham, we do tend to measure T3 fairly routinely as it does give you that ‘supercharged’ element of the thyroid hormones and can also give you some clues about what is going on underneath and what the disease process might be. (JL)

What is the highest TSH you have ever seen?

I have certainly seen a TSH in the several 100s in a baby with CHT but also in a child with acquired hypothyroidism, where the thyroid has been ‘beaten up’ by autoantibodies. We know that long-standing hypothyroidism in children can actually give rise to some quite significant problems. We do not see this very often, and you would not usually expect to see the same problems with a TSH of 7 or 8.

A very high TSH level can also stimulate the ovaries and cause a bit of bust development although you do not see this very often. So, if children are going into puberty very early, we would always check their thyroid function. (TC)

Can a head injury cause thyroid problems in children?

My thought would be it could potentially cause central damage to the pituitary axis, rather than directly to the thyroid. It could also perhaps cause transient problems: We know that when you are poorly your body responds by suppressing all of your thyroid hormones. This is called ‘sick euthyroid syndrome’.

Going back to the question my two thoughts are: If the child is really unwell due to the head injury this could be ‘sick euthyroid syndrome’. Or has the part of the brain that is controlling the thyroid hormones been damaged? (JL)

How do you manage patients with subclinical hypothyroidism?

In patients with subclinical (borderline) hypothyroidism, the TSH is starting to go up a bit. The brain is having to work a bit harder to signal to the thyroid to work harder but actually the thyroid is able to keep up in most instances.

Sometimes TSH and thyroid hormone levels can go out of range for other reasons. For example, some children who are overweight can have a slightly raised TSH. You could easily conclude that the cause of this child being overweight is because they have a raised TSH. In reality, we know it is the other way round in many cases. In a lot of heavier people, they have become heavy and their TSH has gone up as a result - but we do need to keep an open mind about it.

I would normally check antibodies in children who develop problems mid-childhood, as opposed to those with congenital hypothyroidism. If they have antibodies that are attacking their thyroid gland, then we know they are at a higher risk of going on to develop fully-blown hypothyroidism (usually defined as a TSH around 10 or more, as a rule of thumb). What I cannot tell you is when! I think for that group, we might be checking every 6 to 12 months. Where they develop new symptoms, we might check earlier. So, I would certainly be having a discussion with patients about symptoms and what is realistically likely to happen to the thyroid hormones.  

I think we also need to be a little bit careful when prescribing medicine that a young person may potentially have to take for the rest of their life. A trial of thyroxine may be entirely appropriate in someone with symptoms potentially linked to thyroid dysfunction who has mild TSH elevation, although some studies indicate that many people feel no different. So, I make sure the young person understands that a trial of treatment can sometimes be quite useful. I am very wary about then discharging a patient who had a subtle increase in their TSH to their GP without potentially having a trial off treatment as we know sometimes the TSH elevation is transient. (TC)

Yes, we know that a proportion of these children who have borderline raised TSH levels with normal thyroid levels, will have completely normal function on follow-up – typically somewhere between 4 and 12 months later. So, if you put all of those children immediately on levothyroxine, you are committing the majority of them to lifelong treatment. At some future point, a doctor may say ‘you can come off treatment, you are fine’ but for most children they continue on it once they are on that pathway.

So, it is reasonable to re-check thyroid function at around eight weeks before starting or if thyroxine has been stopped because of uncertainty regarding current thyroid status. Some of the children will then become overtly hypothyroid at this time. You can then start or restart treatment again with the knowledge that you are actually doing good for that patient in the long run.

Some patients may want to  carry on with slightly raised TSH and slightly high antibodies on the basis that this is under regular review. Typically, I would follow up this sort of patient every six months or so unless symptoms develop sooner. (JL)

Does iron deficiency come hand in hand with thyroid function?

Iron and thyroid levels are normally picked up because someone has come in feeling very tired. So, we would do a full blood count, which includes testing for iron and thyroid function. Iron deficiency is very common and hypothyroidism is relatively common.

It is important to be aware that iron tablets can interfere with levothyroxine. So, when taking both treatments, you need to separate these out by a few hours. (JL)

My daughter is very tired. Is this due to her thyroid condition, or could something else be going on?

Whenever I see someone who has a slightly raised TSH and has tiredness, I always think it is important to keep an open mind and not blame the poor old thyroid for absolutely everything. Sometimes you find something else, such as coeliac disease, or deficiencies in things such as iodine or vitamin D. (TC)

We know you have ‘normal’ thyroid function tests they may not be normal for that person so they can be symptomatic within the normal range. So, I keep an open mind.

Then, on the other hand, because the symptoms of hypothyroidism can be so varied and non-specific, there is a temptation in patients with hypothyroidism to attribute every symptom to the condition. If a patient’s biochemistry is looking good, then it is good to keep an open mind and consider whether there may be anything else going on.

For example, we know that teenagers’ body clocks are different and they find getting up early really difficult. So, some of it can be down to this. Teasing out what is normal and what is abnormal at that age is helpful.  We also sometimes need to keep our general paediatric hat on so we can identify whether there are, for example, gastric problems, coeliac disease, iron or vitamin D deficiency, or other underlying health conditions etc. We also try and spot ‘red flags’ where we think there may be something abnormal going on and try to investigate these further. (JL)

When is the best time to give levothyroxine?

Consistency is good because if we build habits we are much more likely to take it. So, my number one rule is, the best time to take it is the time when you are going to take it! So, if that means next to your toothbrush in the morning, that is great. Or if that is in the evening, at the same time as you are reading your book, then I will take that as well.

In adults, we talk about not giving levothyroxine with food. In paediatrics, that is not generally something that we routinely advise. And certainly, babies will often take it with a feed so that is not so much of an issue. I think avoiding taking it with soya and iron is important. I would rather children take it consistently rather than sometimes taking it in the morning, and sometimes forgetting a dose.

I also recommend pill boxes for helping teenagers to remember to take their dose.  With these, you know whether your teenager has taken it or not and can remind them to take it when they get home. Although this is not ideal, it is better than not taking the dose. Indeed, if my teenage thyroid patients know they have forgotten to take a dose, I allow them to take a double dose the following day. I think advice may vary a little between doctors but we have found that this gives better control overall. (JL)

My child has increased anxiety levels since his levothyroxine dose increased. Is this normal?

If the doses change is very recent, you generally would not want to check thyroid function for a few weeks otherwise you are not going to see that change. I would also look at other things that may be going on with the child, at school and at home.

So, it is about having an open mind and thinking about whether there is good evidence of it being thyroid related or whether it could be other things.

Certainly, speak to your clinician and perhaps suggest whether it would be reasonable to go back to your original dose and see whether suddenly things get better and have a bit of a trial. There may be good reasons not to do but it would be a reasonable question.

Can having a thyroidectomy make patients feel sick after eating certain foods?

I think in that situation I would be checking for other things, especially if the patient had Graves’ disease. Because there is an association between autoimmune conditions, such as Graves’, and other autoimmune conditions. If you are on an appropriate dose of levothyroxine, I do not think you would expect to feel sick because of your thyroid status. I would suggest you discuss these issues with the paediatrician to see whether there is anything else going on

My daughter’s consultant is going to trial her off carbimazole after three years being treated for Graves’ disease. Her antibodies are still a little high. What should I be looking out for over the next few months as an indicator of how her body is coping? What are chances of success?

Graves’ disease is one of those areas where this is still a lot of work to be done and questions to ask such as: How long should you be on carbimazole for? Do you get more benefit if you are on treatment for longer and how much more benefit do you get if you are on it for even longer?

We know that typically people with Graves’ disease have a different antibody than those patients who have hypothyroidism. That antibody will usually stimulate the thyroid to produce out of control levels of thyroid hormone. Just to be confusing, it can also sometimes block the thyroid gland. This means it can move from hyperthyroidism to hypothyroidism and we cannot usually tell the difference between the antibody that is stimulating it and the antibody that is blocking it in a standard lab test.

After you have had Graves’ disease you may stop your treatment and then be fine. Others will have another episode of hyperthyroidism and their doctors may offer more treatment to try and turn the thyroid gland off permanently.

If your daughter still has those antibodies around then is she more likely to relapse than someone who does not have antibodies any longer. In my experience, patients generally have very similar symptoms that they had the first time around. (JL)

Yes, it is quite a contentious subject knowing how long to treat for. There are studies that have suggested that maybe we should be treating people for longer. There is some evidence, maybe not the best evidence, that the longer you are on treatment, the less likely you are to relapse. So, the advocates of lengthy treatment would say there is no harm in stopping every now and again, as people know what signs and symptoms to look out for. If we are going to stop then generally we would only do so if the thyroid receptor antibodies are low. If we monitor people carefully, we would pick up any return of the overactivity sooner rather than later.

So there is a school of thought that treating people for a number of years is entirely reasonable. I do not think doctors would suggest patients go on a trial off carbimazole unless their antibodies are low. Ideally, we would like to know early on who was going to relapse when the antithyroid drug is stopped after two to three years. And this is an area where people are doing a lot of work at the moment.

And researchers are also looking at new treatments, besides carbimazole, that can make the immune system behave a bit better and stop attacking the thyroid gland. So, it is quite an exciting time in the field of Graves’ disease. Going back to the original question about stopping the antithyroid drug, I think it is probably not wise to stop the antithyroid drug if the stimulating antibodies can still be measured in the bloodstream because of the likelihood of the condition coming back. Unfortunately, even if the antibodies are low, it is still likely that is going to come back (60-80% chance) but it is almost certain to come back if the antibodies are present. (TC)

My son has relapsed after two years off medication and is now back on carbimazole. Is it ok for him to have carbimazole for another two years until he has finished his A levels?

Thinking about Graves’ disease, I do not think ultimately there is one treatment out there that is head and shoulders above any of the others. If you are on antithyroid drugs, you have got this holy grail of remission off treatment but we know, certainly in the short term, this is not very likely. The beauty of surgery, or in older young people radioiodine, is that it gets rid of the problem to a large degree but you then need thyroxine replacement so it is not really a definitive cure.

One of the quality of life studies we did in young people showed that those people who went on to have their thyroid removed or have radioiodine treatment, generally speaking, did not regret it, some even wishing they had had it earlier. I think for some young people taking antithyroid drugs with unstable thyroid function is a real pain. So, sometimes I have recommended to families that given all the ups and downs, the simplest option would be to have definitive treatment, even though this means they will be on replacement thyroxine long-term. I think whatever is decided, the patient needs to be at the heart of the decision-making process. (TC)

What are the long-term effects of being on carbimazole?

I would like to mention an important message about Graves’ disease: If you have had your thyroid gland turned off either with surgery or with radioiodine, and are ever planning a family in the future, it is important to have a conversation with your doctor about your history of hyperthyroidism. This is particularly the case for females because we know that these antibodies can cross the placenta and can affect the baby.  Even if you have had your thyroid gland removed these antibodies may still be around.

In fact, in all thyroid disorders it is really important that pregnancies are planned and that thyroid function is as well controlled as possible.

In terms of the long-term effects of carbimazole, I am not aware of a huge amount of data in children. It is generally fairly well tolerated and we warn people about the side effects when they first start on medication. For example, if you have a sore throat or fever, we ask people to stop taking their antithyroid medication and have a full blood count checked the same day. Occasionally liver function can be affected as well but these would normally occur early on in the treatment. Nevertheless, symptoms should always be checked by a medical professional.

My daughter has Hashimoto’s disease (autoimmune hypothyroidism). Is my other daughter likely to develop it too?

With all autoimmune conditions, there are some genetic markers that make you more likely to develop them. I would be looking for symptoms but I would not be screening siblings purely because one of them has developed hypothyroidism. (JL)

If these were identical twins then the likelihood would be substantially increased. I might check thyroid function occasionally, especially to see if antibodies were present, and this would help to determine how often we would need to test.  I would definitely check it if there were relevant symptoms to suggest thyroid dysfunction. (TC)

June 2022