Dr. Mike Smith (Host): Welcome to Pediatrics in Practice, a CME podcast. I'm Dr. Mike. And with me is Dr. Jake Dahl from Children's Mercy. Today, we'll discuss pediatric thyroid disorders, what pediatricians need to know about diagnosis, referral, and surgical care.

Host: Dr. Dahl,

Dr. Mike Smith (Host): welcome to the show. I want to start off with what are some of the most common pediatric thyroid conditions you manage?

Dr. Jake Dahl: So in pediatrics, we tend to manage these conditions as a team. And so, we work very collaboratively with our colleagues in endocrinology, radiology and other specialties to manage both benign and malignant conditions. The most common thing we see are just benign nodules, which are just little cysts in the thyroid gland that have no real pathology or negative impact on the patients.

Host: And so, how does a patient enter your care? I would assume there's some referral process for you, right? Could you describe that for us?

Dr. Jake Dahl: Yeah. So, there's a couple of ways that patients enter our care. One of my colleagues in endocrinology, Dr. Mitre, has a thyroid nodule clinic. And some patients are referred to that clinic, they have a medical evaluation. And then if they are potential candidates for surgery, Dr. Mitre refers them directly to me. And then, sometimes the exact opposite happens. Patients are referred directly to me. I will order basic laboratory and imaging workup, and then refer them to Dr. Mitre for his input. And then, as a team, we discuss treatment options, and then present those options to the family.

Host: You mentioned most of the cases, luckily, right, are benign nodules. What happens with those patients? Do they just go back then to the primary care, or do they even stay with you for a treatment plan?

Dr. Jake Dahl: It depends on how big the nodules are and the ultrasound characteristics, but the majority of those patients, we provide reassurance, and then recommend they followup with their primary pediatrician and maybe get a repeat ultrasound every year or so depending on symptoms.

Host: Now, when it comes to more malignant type nodules, how often do you see that?

Dr. Jake Dahl: So, the incidence of thyroid cancer in children and adolescents is actually increasing. We're seeing more and more of it. And the majority of the cases we see are what are termed differentiated thyroid cancers, with papillary thyroid carcinoma being the most common.

Host: Well, what do you think is going on there? Why the rising incident?

Dr. Jake Dahl: The honest answer is we're not sure. There's likely some component that we're better at diagnosing these. And so, we're picking up more patients at an earlier age. But the counter to that is that pediatric thyroid cancer tends to be more aggressive, it tends to have more metastases to cervical lymph nodes than adult cancer. So, it's really not well understood. But our team here is working on some research projects to help us understand that better.

Host: Well, anytime there's a rise in incidence of any disease, we're better at diagnosing, right? That could always be a part of it. But in kids, especially with these aggressive cancers, I'm sure there's some research going on trying to figure out, is it just we're better at diagnosing or is it something else, right?

Dr. Jake Dahl: Yeah. And I think that a lot of that, what we're going to find is related to autoimmune thyroiditis and almost every single patient that we see with these differentiated thyroid cancers has some level of autoimmune disease in the pathology background. And I think we just don't understand enough about our own immune systems to fully elucidate the mechanism through which this autoimmune thyroiditis turns into a differentiated thyroid cancer.

Host: Yeah, I definitely want to talk about that coming up. But before we get there, I want to go back to more the primary care pediatrician. And when they're faced with an abnormal thyroid lab or on physical exam, maybe a thyroid nodule or they've done some imaging and they see it, what are some of the steps they need to take first before referring?

Dr. Jake Dahl: So if there's laboratory abnormalities, just getting a dedicated thyroid ultrasound is the next step. And depending on what that looks like, either a referral to endocrinology or myself. If there's abnormalities on ultrasound and these are well-characterized abnormalities, such as microcalcifications within the nodules, those patients need an urgent referral to, again, either endocrinology or myself for an expedited workup.

Host: How does this differ in adults, you know, with adults, we know that certain nodules can be cold, as we say, or hot causing hyper or hypothyroidism. Is that the same thing in kids? Or do they not experience the ups and downs of thyroid hormone?

Dr. Jake Dahl: So, more and more commonly we're seeing that as well, and that would fall into our benign disease. As I mentioned earlier, these benign colloid cysts, those are cold nodules, nothing needs to be done. We actually see a decent number of hot nodules or nodules that are actually just secreting thyroid hormone without the appropriate endocrinologic HPA axis controls, if you will. And those patients actually most commonly go to our endocrine colleagues. They usually get a thyroid uptake scan, which is a nuclear medicine scan that will localize the hot nodule. And then, they come on over to us. And we'd usually just remove half the thyroid gland for the hot nodules. And then, the patients symptoms return to baseline over a course of a couple weeks.

But hyperthyroidism is a miserable condition. And so, these patients tend to be pretty symptomatic, although the symptoms can be vague. And so, I think primary care pediatrician should have a low threshold to order TSH, free T4 levels, or even a thyroid ultrasound.

Host: Let's go into autoimmune now. You know, you brought this up that this is increasing, you're seeing it more and more. What signs should prompt earlier testing then? And how does early management impact long-term outcomes here, if we recognize these autoimmune issues earlier?

Dr. Jake Dahl: Well, I think, first, like a lot of thyroid conditions, the symptoms are really so global that they can be hard for anybody, not just a primary care pediatrician to diagnose. But, you know, signs of decreased thyroid function, lethargy, hair and skin changes, menstrual period changes in the appropriate age range, all those things that we learned in medical school are true. And that should trigger some basic workup in primary care, very similar to what I just said, some basic labs and ultrasound. And often, what you see in the ultrasound is just a diffusely enlarged, inflamed thyroid gland.

And as long as those patients have normal thyroid function tests, we really don't recommend any treatment. But we do know those are the patients who are at risk for having hypothyroidism secondary to the autoimmune thyroiditis. So, they probably do need some type of laboratory surveillance and imaging surveillance.

And then, we also know that these are the patients who are likely predisposed to having these differentiated thyroid cancers so that would trigger the primary care to do a more thorough neck exam or thyroid exam when you're seeing these patients. And if there's any concerning findings, again, just jump to an ultrasound. We love ultrasounds.

Host: In clinical medicine, when you are faced with several different symptoms of a patient, it almost seems like it's never a bad idea to do a quick check of the thyroid, right? Maybe go ahead and throw some labs in there, just in case, because so often we go down these rabbit holes and a simple TSH could have helped us out, right?

Dr. Jake Dahl: I agree. But again, these symptoms are vague. And it's hard for even people who focus on this area of practice to get these diagnoses right all the time.

Host: In clinical medicine, as a, you know, primary care doctor, we need a little sticky note, "Hey, don't forget thyroid." Don't forget to check that, right, just in case.

Dr. Jake Dahl: Yeah. I don't know how primary care docs keep up with all the things they're supposed to keep up with. I can barely keep up with the things in my very limited practice.

Host: Well, they are some of our best clinicians, no doubt. What clinical or diagnostic factors typically indicate that surgery is going to be necessary for a thyroid condition?

Dr. Jake Dahl: So for the benign conditions, the most common thing is that hot nodule. And again, usually, the recommendation is removing part of the thyroid. In kids, like a big goiter or diffusely enlarged thyroid causing symptoms such as swallowing difficulties, breathing difficulties, difficulties with phonation is pretty rare, although we do see it.

In terms of the patients with concern for malignancy, once they have a thyroid ultrasound that shows concerning nodules, they'll go see our friends in interventional radiology for a fine-needle aspiration biopsy, which is ultrasound guided and done under sedation as an outpatient. And then, once we have those results, then we'll talk to the family about the need for surgery. And the way those results kind of fall out is either it's benign, in which case we'll probably just repeat an ultrasound in six to 12 months. And depending on what the nodule looks like, that may be an ultrasound that either endocrinology or I order and followup with.

And then, if it is concerning for malignancy, then we have the discussion about surgery. In the current state right now for these differentiated thyroid cancers, we remove the entire thyroid gland, as well as do a staging—what we call central compartment neck dissection. So, we remove lymph nodes around the thyroid, down the tracheal esophageal groove. And if there's other lymph nodes on preoperative imaging, then we'll do a formal what we call selective neck dissection. And we can figure all this out based on imaging and the FNA biopsies preoperatively.

For patients who end up in the gray area, so not definitely benign, not definitely malignant, that's a real gap. Because the treatment options are either just remove half the thyroid in one surgery, get final pathology. If it's malignant, go back and remove the other half and the second surgery, which nobody's really excited about, or just go ahead and remove the entire thyroid gland. And if there's no malignancy, well, then the patient got a total thyroidectomy and needs thyroid hormone replacement for the rest of their life for no great reason.

There are some commercially available genetic testing kits that we can use to test on that FNA sample. But they're only validated in adults and they're only FDA approved in adults. So, do we trust the results, because we know the pediatric thyroid cancers behave differently? I'm not so sure I do. And the other thing is payers do not want to pay for these genetic tests, because they're not FDA-approved for patients under 18 years.

Host: Yeah. Well, how often are you faced with this question about it? Is this malignant? Maybe it's not. We're not sure. How often does that actually happen?

Dr. Jake Dahl: It's pretty common. The grading scale that we use, the cytopathologies we use for the FNA analysis is essentially a six-point scale. And so, there's two ends of it that are really clear.

Host: And then, the middle—

Dr. Jake Dahl: Yeah. What do you do?

Host: Yeah. So, you proposed—and there's two options there. You just remove the nodule basically and followup or remove the whole thyroid. What do you usually do in those cases?

Dr. Jake Dahl: I talk to the patient and their family about their options, and try to guide them through it and help them make the best decision for them.

Host: When you think about surgery in general, you know, with AI and robots and all this kind of stuff, has the surgery you do for thyroid nodules, has that changed at all in the past few years? Or do you see advancements coming down the line?

Dr. Jake Dahl: Well, I think, in terms of the major advancement, there's some new systems available to help us identify parathyroid glands intraoperatively. So, hypoparathyroidism is one of the most common risks of thyroid surgery for a total thyroidectomy. And while not life-threatening, if you have a permanent hypocalcemia that is not fun. And then, you apply that to a 12-year-old, 15-year-old, that's something we really, really want to avoid. And so, the ability to use these new systems to help us identify parathyroids and preserve them is really an advance.

In the terms of the robots, people are doing it in adults, and they're doing transaxillary transoral thyroids in some places, not super common in the US. But the expense and, I think, the risks for that are higher. I can do these surgeries through a two to four-centimeter incision in the low neck that we close very meticulously and still see all the nerves, blood vessels, trachea, everything I need to see.

And so, for right now, I think our traditional surgical approaches are going to stay around. Now, where I do see an area for innervation is this genetic testing. We know what the high-risk genetic mutations are the drivers of these differentiated thyroid cancers. And so if we had that information upfront, we can much more accurately counsel patients and families regarding the indeterminate nodules on the FNA biopsy.

Host: It's really interesting, isn't it? The personalized medicine, understanding that cancers, even though it's the same cancer, technically, it could be very different in different people and act differently. And so, that could be very powerful. The parathyroids, that's an interesting thing because I don't do what you do. I'm a radiologist, I don't do surgery. But when I was a medical student, all of the anatomy books made it very easy to find the parathyroids. So, I don't know what the problem is, Dr. Dahl.

Dr. Jake Dahl: They're wrong. I like to tell patients and families that our patients don't read the textbooks. Parathyroids look like little five millimeter, 10 millimeter drops of fat in the neck.

Host: But the books make them look like they're headlights.

Dr. Jake Dahl: Let me tell you, they are not headlights. They look like fat. Sometimes they look like little lymph nodes, and they can be anywhere around the thyroid and even inside the thyroid.

Host: Well, that is interesting innovation then, isn't it? Because that's going to help out, I think, or avoid a big side effect of surgery. I want to kind of wrap this up with counseling and how do you counsel families and their pediatricians about all of this? You know, if it needs to be surgery, the risk recovery, what's your approach to the counseling aspect of this?

Dr. Jake Dahl: You know, I try to just be honest and straightforward, transparent, while at the same time, reassuring the patients and their parents that this is a common operation in our hands here at Children's Mercy. Myself and my partner, Dr. Brown, we do these surgeries together to attending surgeons, both fellowship-trained ENT head and neck Surgeons, and try to answer any of the questions they may have about what they'll experience.

I'll be honest with you, most patients are more worried about anesthesia than they are the surgery. So, we talk about that. We talk about not taking stitches out, because the only stitches we use are absorbable. And talk about postoperative pain management. We do talk about the risks, including risk to the recurrent laryngeal nerves and the hypocalcemia amongst other things.

But I really try to put that in the context of these risks are exceedingly rare and we do everything we can to prevent them. And, you know, if they do happen, we have a great team that can help work through them.

Host: Very good.

Dr. Dahl, this has been fantastic information. I really appreciate you coming on and sharing your expertise.

Dr. Jake Dahl: Dr. Mike, thanks again for having me and allowing me to share my clinical passion with you and your audience. If referring pediatricians or other providers in the community have questions about the referral process or think they have patients that need to be seen by our team, they can reach out to us directly. All of our contact information is on the Children's Mercy website. For new patients with concern for thyroid cancer, our goal is to get them in for an evaluation within two weeks.

Host: For more information, you can go to cmkc.link/cmepodcast. If you enjoyed this podcast, please share it on your social channels and explore our entire podcast library for topics that interest you. This is Pediatrics in Practice, a CME podcast. I'm Dr. Mike. Thanks for listening.