Pediatric endocrinologist Amanda Flint, MD, tackles another common medical issue for Down syndrome patients – thyroid disease.
Dr. Vellody: Hello everyone, and welcome back for another Down Syndrome Center of Western Pennsylvania podcast. I am your host, Dr. Kishore Vellody. Today we are going to be tackling another common medical issue that we see in people with Down syndrome, and that's thyroid disease. Joining me today is Dr. Amanda Flint who is a pediatric endocrinologist at Children's Hospital of Pittsburgh. Dr. Flint, thanks so much for joining us today to share your expertise. Before we start, could you please give us some background information on your training?
Dr. Flint: Yeah, of course. I went to medical school in Albany, New York which is in upstate New York. Then I went to do residency actually in combined internal medicine and pediatrics at the University of Michigan. I did my Endocrinology training here at the Children's Hospital of Pittsburgh. For the past 2 years or so, I've been here on faculty.
Dr. Vellody: You really moved around with your training but we're glad you've found a home here. Now, moving forward with our topic for today. As you know, we send a lot of patients to see you and your colleagues in Endocrinology. Can you tell us what are the most common types of endocrine issues that can happen in Down syndrome?
Dr. Flint: There's a few things that we do worry about. Probably the biggest thing is thyroid disease, both underactive and overactive thyroid is more common in kids with Down syndrome so that's something that we actually screen for routinely.
Dr. Vellody: Well, let's keep our focus on thyroid disease then for today's podcast. How common are thyroid problems in kids in general? How much more common are they in kids with Down syndrome?
Dr. Flint: Thyroid disease in general is pretty common. It's one of the most common things that we see in kids that we follow in our Endocrine clinic who have any number of different underlying medical problems or none at all. In Down syndrome, it's probably even more common. We know based on big studies of lots of patients with Down syndrome that as many as even 50 percent of adults with Down syndrome will end up with some form of thyroid disease. We think that a good chunk of that starts in childhood. Probably about half of the people that will end up having it will develop it by the age of 8. So, it's pretty common. Congenital hypothyroidism, or hypothyroidism that babies are born with, is also more common. Whereas the average child born would have about a 1 in 4000 chance of having congenital hypothyroidism, in kids with Down syndrome it's probably closer to about 75 in 4000. So, it's certainly more common.
Dr. Vellody: Thanks. So thyroid disease is certainly a lot more common in people with Down syndrome. What are the types of symptoms that hypothyroidism can show up with?
Dr. Flint: In terms of monitoring symptoms, we look at usually subtle things at first. Fatigue is a common complaint. Feeling cold all the time when other people are comfortable - we hear of kids wearing lots of clothing or heavy blankets in the summer, for example. We do see some weight gain often with that. In particular, we see weight gain without height growth. So if the height is slowing down and the weight gain is continuing, that makes as suspicious. Other symptoms might include drier skin. Another big one is constipation.
Dr. Vellody: Well, listening to that list, I'm sure that many of our listeners are thinking the same thing that I am. Those symptoms sound like so many of the kids who I follow with Down syndrome who have perfectly functioning thyroids!
Dr. Flint: That's true. We often see kids with Down syndrome or without Down syndrome who complain of a lot of those things. Their parents or their physicians are worried about hypothyroidism, and their thyroid function is completely normal. So sometimes it can be very hard to sort out and that's why in Down syndrome, when kids are at such high risk, we like to do screening so we can try to catch that problem maybe even before the symptoms are starting.
Dr. Vellody: I don't want to move away from this important point just yet. We have met some families who have elected not to screen their children for thyroid disease as recommended because they have not noticed any symptoms of thyroid problems. Just so we're all clear, you are saying that screening kids with Down syndrome is important, even if they don't show symptoms of hypothyroidism?
Dr. Flint: Very true, yes. I think it's very important to screen. In part, if you can prevent the symptoms from developing . . . often we catch this before any symptoms have developed, and we can start treatment to prevent the symptoms. Another important point that I haven't made yet is that the thyroid hormone is very important for development. In kids with Down syndrome, who are already at a bit of a disadvantage in terms of their developmental skills, its very important not to give them another reason to struggle.
Dr. Vellody: Thanks. Part of why I love working in the Down Syndrome Center is for that very reason. We want to make sure that kids with Down syndrome are given every advantage to succeed. Screening for the most common conditions, especially easily treatable ones like hypothyroidism, can prevent long term problems. We've seen this time and again. So, what do you think? When should the thyroid screening start to happen?
Dr. Flint: Every baby that's born, no matter what, will have newborn screening. They have that testing done in the hospital. That's just a small spot of blood that checks for a whole host of conditions. In Down syndrome, particular attention is paid to the thyroid tests. So that's done at birth in everybody. Then for kids with Down syndrome, we like to test them again with a blood draw at about 6 months of age and again at a year. After that, we'll test it once a year, assuming they don't develop the disease or symptoms of the disease, in which case we might screen them sooner.
Dr. Vellody: Ok, thanks. So, after checking the thyroid testing a few times over the first year of life, they then get annual thyroid checks for the rest of their life. So, they must be at risk for developing hypothyroidism at any point?
Dr. Flint: Yeah, absolutely. So they're at a higher risk to have developed that even before birth or at birth but also to acquire it down the road. We really see it developing at any time and that's why we screen yearly after the age of one because it really can develop at any time.
Dr. Vellody: Why would a thyroid gland change from one that is functioning normally to one that just stops working right?
Dr. Flint: The most common reason to acquire hypothyroidism, no matter whether a child has Down syndrome or not, is due something called autoimmune thyroid disease. In that condition, essentially the immune system gets confused and thinks that the thyroid is like a virus or bacteria and actually attacks that. Often when we do detect hypothyroidism in kids with Down syndrome, or any child, we will also check antibodies to the thyroid gland. If those antibodies are present, it might make us a little bit more worried that the child may also be at risk for other autoimmune conditions. That includes, from the Endocrine standpoint, type I diabetes but also celiac disease and a variety of other things.
Dr. Vellody: Okay, so now that we know some of the background about hypothyroidism, can you tell us how you decide when to start treatment?
Dr. Flint: Sure. So we look for lab results to guide us. Certainly if a patient is symptomatic, we may be more inclined to treat than just to watch and wait. In general, we look at two different lab parameters. One is called the TSH (thyroid stimulating hormone) and the other is called the free T4 (thyroid hormone itself). In general, the first thing that we see is the TSH actually goes up. That's kind of like the thermostat in your house. It goes up . . . the thermostat turns on when the heater isn't make enough heat . . . it needs to turn on. It's like the TSH is trying to tell the thyroid, "Hey, you need to work a little harder." So, for a while, usually that's enough – the thyroid hormone will remain normal. There's a point where that starts to fall. Certainly, if we see a low free T4 level meaning that there's not enough thyroid hormone in the body, we will start treatment. We also think that once the TSH gets above a level of around 10, that probably means that things are going to continue to get worse. To try to prevent the onset of more symptoms, we actually like to start treatment, usually around that time.
Dr. Vellody: And what is the treatment? Is it complicated or difficult for families and patients to do?
Dr. Flint: So, the good news is hypothyroidism is actually pretty easily treated. We just give the thyroid hormone in a pill form, and your body doesn't mind if it gets it in a pill form versus from the thyroid making it itself. It's usually just one pill once a day, and that's all there is to it.
Dr. Vellody: Is there any specific advice for how the medication should be taken?
Dr. Flint: We do advise giving it on an empty stomach if at all possible, but the important thing is consistency. So if you always give it with your child's breakfast, that's usually fine. We just may need to increase the dose a little bit because food will affect how well it's absorbed. For smaller children who can't swallow pills, there's not really a good liquid form of the medicine, so we usually just advise crushing it and either mixing it with water or a small amount of formula or a small amount of food.
Dr. Vellody: Why does it have to be in a small amount of fluid? Can't they just put the medicine in the whole bottle?
Dr. Flint: We usually advise against doing that mostly because, if for some reason the child doesn't finish the bottle, then they haven't gotten all of their medicine. It's best to really put it in a small amount so that you know that they'll get it all in.
Dr. Vellody: Ok, I think that's a great overview of hypothyroidism. Now lets switch gears and talk about hyperthyroidism. Is that an issue in Down syndrome?
Dr. Flint: Yes, so actually hyperthyroidism (overactive thyroid) is more common in kids with Down syndrome as well. It's not anywhere near as common as an underactive thyroid. That's true of other kids as well. It's much less common, but it is something that we look out for as well.
Dr. Vellody: And what are some of the symptoms that you see with hyperthyroidism?
Dr. Flint: It's essentially the opposite of hypothyroidism. We look at kids who are hot all the time where they're wearing no clothing despite it being winter, where they're kicking off their covers at night. We see maybe more sweating going along with that. We'll see no so much diarrhea but definitely more frequent stooling. Sometimes kids will complain that their skin is really soft or kind of moist instead of the dry skin that you see with hypothyroidism. Also, they may appear kind of jittery. Also, if they're able to complain of this or you may notice that they have a higher heart rate. That's an effect of the higher thyroid levels. Also, instead of weight gain, you may see some unexplained weight loss.
Dr. Vellody: So, once it's suspected, how is the diagnosis made?
Dr. Flint: It's essentially the same way. We check the same hormone levels. In this case the TSH (thyroid stimulating hormone) would be low or undetectable even. Again, it's your body's way of trying to shut off the thyroid hormone whereas the thyroid hormone itself (free T4) would be high.
Dr. Vellody: Is the treatment just as easy with hyperthyroidism as it is with hypothyroidism.
Dr. Flint: Hyperthyroidism treatment is a little bit more complicated. There a medication that we often use, and that's probably the first thing we go to in children. It's a little bit more complicated than one pill once a day. It usually requires treatment at least three times a day, at least at first. Then, very careful monitoring. We tend to monitor these kids a little bit more closely because of the negative side effects can be much worse. There are some other options that would be considered on a case by case basis.
Dr. Vellody: Ok, wow! I don't know about you, but I feel like we covered a lot of information in this short podcast! I'd like to take this opportunity to thank Dr. Flint for joining us today on the podcast.
Dr. Flint: Thanks very much.
Dr. Vellody: I also would like to thank you, our listeners, for your continued enthusiasm for this podcast. There are several more on the way so stay tuned. Until then, enjoy the rest of this month of October as it is Down Syndrome Awareness month. Take that extra time this month to let your loved ones with Down syndrome know how much they mean to you! Bye for now!