Dr. Corinn Cross (Host): Welcome to Pediatrics in Practice, a CME podcast. I'm Dr. Cori Cross. Today, we're exploring hypertension in the pediatric patient. To discuss this topic, we are very lucky to be joined by Dr. Douglas Blowey, who's the Director of the Hypertension Clinic in the Division of Nephrology in the Department of Pediatrics at Children's Mercy in Kansas City. Dr. Blowey also serves as the Chief Clinical Integration Officer and the Medical Director for Children's Mercy Integrated Care Solutions. Dr. Blowey, thank you for taking the time to join us this morning.

Dr. Doug Blowey: It's my pleasure. Thank you for the invitation.

Host: So in the past, hypertension was basically considered an adult condition. How common is high blood pressure in children today? And can you explain to us why it's becoming so much more prevalent?

Dr. Doug Blowey: So, high blood pressure is actually much more common in children than many people realize. Current estimates suggest that there's about a 2% to 5% incidence of hypertension in children and adolescents. There's even a higher percentage that have blood pressure readings that are considered abnormal, but not in the hypertension range. And then, in children with chronic diseases such as kidney failure, transplantation, the incidence of hypertension may actually approach 50%.

So, the question is why do we think it's becoming more prevalent than historically we thought? And the increase is probably being driven by rising rates of obesity and overweight, along with things such as sedentary lifestyles, poor dietary habits, excess sodium intake, poor sleep, and other cardiovascular risk factors. So while obesity is not the only cause, it has become one of the strongest contributors to primary hypertension in children, particularly adolescents.

Host: That makes sense. Do you think it's also that perhaps we're looking for it more, so we are finding it more than we used to?

Dr. Doug Blowey: Well, probably. You know, the guidelines for hypertension have been out for 20, 30 years now. So, I think, the recognition that high blood pressure can be an issue in children certainly is embedded now in pediatric practice. But if you think 50 years ago when we didn't even measure blood pressure in kids, or we used reference ranges that were adult reference ranges rather than pediatric specific ranges, there may be some difference between the perception of high blood pressure in kids at that time.

Host: So you mentioned the gold standard for how often we check blood pressure in children has absolutely changed over the last few decades. Tell us what the gold standard is and how a pediatric clinician should evaluate hypertension.

Dr. Doug Blowey: So, the gold standard is based on the guideline definition, the last one was put out in 2017, and it defines blood pressure normal values somewhat based on age. So if you're a younger child, say less than 13 years of age, what we consider normal is going to be interpreted using age, gender, and height-based percentiles. So, kind of like a bell-shaped growth curves that all pediatricians are familiar with. So, it's not based on outcomes, but it's based on statistical phenomena, whether you're an outlier would define hypertension. Once you hit 13 years of age, the guidelines now support using adult standards, which are based on outcome for adverse cardiovascular events. And so, in those, rather than using the blood pressure charts, it is simply is 130 over 80 like it is in the adult population.

Host: And how often should we be checking blood pressure? I mean, in our clinic, we check it every time they come in. What's the gold standard there?

Dr. Doug Blowey: Yeah. So, that's reasonable. The simplest would be to say that it should be done once a year at annual well visits in kids that don't have any chronic diseases. But kids that have chronic diseases, whatever you want to call it, diabetes, kidney issues, and even I think obesity should be checked at every healthcare encounter.

Host: And then, you sort of touched on this, but can you explain to our listeners why it is so important to recognize hypertension in children?

Dr. Doug Blowey: Well, the main issue has to do with the risk of future events. So fortunately, high blood pressure in children is usually kind of a silent condition, right? Most kids don't have any symptoms. But we do know that children that have high blood pressure do show signs of cardiovascular injury, including left ventricular hypertrophy, increased vascular stiffness, other markers of accelerated vascular aging. Approximately one in three children with documented hypertension already have evidence of left ventricular hypertrophy.

So, the other thing is that hypertensive kids tend to be hypertensive adults. There's tracking. And usually, a lot of the risk factors associated with hypertension, like obesity, track into adulthood, too. So, it's more about preventing future cardiovascular events as an adult rather than probably really treating any symptomatology in children.

Host: Okay. So, say, you're a primary care clinician, you have pediatric patient comes in, you get an elevated blood pressure reading. What do you do next?

Dr. Doug Blowey: So, the first step really is just to confirm the reading you've gotten. So, many elevated blood pressure measurements are related to anxiety, activity, pain, incorrect measurement technique.

So, the first thing, it should be repeated using the appropriate size cuff and appropriate technique, making sure those are done consistently. If you have elevated readings that persist over multiple visits, you should start evaluating for contributing factors such as obesity, family history, medications, sleep disorders such as obstructive sleep apnea, and lifestyle habits that include activity levels and dietary patterns. Concern for a underlying secondary cause increases when hypertension occurs in younger children, is really severe, develops suddenly, or is accompanied by findings such as abnormal kidney function, urinary abnormalities, or other concerning symptoms.

Host: So when we take our second reading, when we bring them back, it depends on how elevated the blood pressure is. I mean, if it's extremely elevated, we're having them back very soon to retake that blood pressure. If it's slightly elevated, we might wait a few months to do that. That's correct, right?

Dr. Doug Blowey: That is correct. There's not a one-size-fit-all, but I think it's more kind of your clinical perception of how significant it is.

Host: But if we do believe that it is truly elevated, we've already eliminated white coat, doing improper technique, at that time, we should probably get a urine and not wait for the child to come back. Because if they do have underlying kidney issues, that's going to prompt a referral, right?

Dr. Doug Blowey: That is correct. So usually, once you get to the diagnosis of hypertension, then the question is always, well, why? Why would a child have high blood pressure? So, you start thinking about some evaluation, right? Are there things I'm missing here or I want to know about?

And clearly, the beginning stuff can clearly be done in the primary pediatrician's office, and it should not be extensive. You shouldn't be looking for all the zebras and all the crazy stuff. It can be very simple. As you mentioned, a urinalysis is by far the most common thing that is missed when I see patients in referral, that that just doesn't get done for some reason, but clearly is very important.

The other things we typically recommend is if there's no really clear risk factors or anything that you pick up on, serum electrolytes and creatinine. I will get a lipid profile in kids, not because it causes hypertension, but because it's another cardiovascular risk factor we want to be aware of. We do thyroid function study and the urinalysis that you mentioned. And that is about it as far as just a quick screening to make sure there's nothing clearly jumps out at you. And again, that can be done in the primary care provider's office before considering referral.

Host: So if we get those back and they're normal, we can continue to follow up the blood pressure. But if the blood pressure continues to be elevated, at what point should we be referring to a pediatric hypertension specialist or a nephrologist?

Dr. Doug Blowey: There's a good list of things that should prompt your referral. The one, kind of like you mentioned, is that the hypertension persists despite you trying to trial lifestyle modifications, behavior modification type things. So, the things that should prompt a referral would include significant blood pressure elevation, so stage II hypertension, which is essentially blood pressure that's significantly above normal; symptomatic hypertension. Although a lot of kids have things like headaches and dizziness and maybe chest discomfort, it could be associated with hypertension or a result of hypertension, although in most cases it's not. But that should make you think a little bit about they need to be seen. Keeping in mind that when you have really severely elevated blood pressure with cardiac or neurologic symptoms, that's going to be categorized as hypertensive emergency or urgency, and requires immediate management in a hospital setting.So, let's see the specialists, get to the hospital now.

The other group would be children younger than six years of age who have hypertension, because a secondary cause is much more likely to be found. Evidence of kidney disease, you see blood or protein in the urine, or the elevated kidney function test would prompt a referral. You just have a high index of suspicion that something else is going on, that's syn- syndromic associate or something like that. For some reason, they've had, like, an echocardiogram, and they have left ventricular hypertrophy on the echo, or hypertension in a kid with chronic disease, such as, you know, chronic kidney disease, diabetes, or any other chronic medical condition really should prompt a referral to a specialist so they can kind of help confirm the diagnosis, identify underlying cause, and determine whether medication therapy is needed.

Host: Right. And we don't want to wait too long to get them in to see someone like you because these are organs that they're going to have for the rest of their lives. So, we'd like to try to make sure that nothing happens to them. So in summary, is there anything else you'd like to share with our listeners today?

Dr. Doug Blowey: Well, sure. I think we kind of touched on it, but I think recognizing hypertension in childhood provides an opportunity to kind of improve lifelong cardiovascular health. So as pediatricians, right, we're preventative medicine, and this fits perfectly into that.

As I mentioned, children with hypertension are much more likely to become adults with hypertension. And we know that elevated blood pressure can begin causing damage long before symptoms occur. The good news is that hypertension is often treatable. So early recognition kind of allows families and providers to implement lifestyle changes and when necessary, medications that can lower blood pressure and reduce the risk of future heart disease, stroke, and kidney disease.

And I think the important thing is that the goal is not simply to treat a number, but to promote kind of lifetime of cardiovascular health. That's the reason we check blood pressure.

Host: Absolutely. Dr. Blowey, thank you so much for joining us today and sharing your expertise on such an important topic.

Dr. Doug Blowey: Very much appreciate the opportunity.

Host: And as a reminder to our audience, don't forget to claim your CME credit after listening to this fascinating episode today. You can do so by visiting cmkc.link/cmepodcast. That's cmck.link/cmepodcast, and clicking on the Claim CME button. If you enjoyed this podcast, please share it on your social channels and check out the entire podcast library for topics of interest to you. I'm Dr. Cori Cross, and this has been Pediatrics in Practice, a CME Podcast.