Chapters Transcript Muscle Weakness/Hypotonia for the General Pediatrician Erin Langton, MD, presents on how to examine newborns and young children for tone, strength, and reflexes. Um, thanks everyone for being here. Um, we're gonna talk about weakness and hypotonia. I titled this Pearls for the pediatrician, but this really applies to, um, a wide variety of pediatric specialties, um, and I myself review the content that I'm gonna share with you on basically an annual basis, um, so I think it's pretty high yield across the board. Um, I have no financial disclosures or conflicts of interest. Um, introduction, so a little bit about me. Um, my name is Erin Langton. I'm an assistant professor in neurology here at WashU. I'm actually a first year attending. Um, I was born and raised in Lancaster, Massachusetts, and did medical school, college and medical school down in Virginia. I went to Eastern Virginia Medical School and then moved here for residency, um, in pediatric neurology and uh neuromuscular fellowship. Um, So I'm a first year attending in um with a clinical footprint that spans child neurology, um, pediatric neuromuscular, um, and some adult neuromuscular as well. I do EMGs, ultrasounds, um, and an adult muscular dystrophy clinic. Um, so agenda, what are we gonna cover today? We're gonna talk about weakness and hypotonia in, um, children, especially young children, and why it matters, um, to recognize it. We are going to spend most of our time reviewing how to examine a newborn and young child for tone, strength, and reflexes, and I'm gonna share a lot of videos, um, of normal and abnormal, um, babies and children. To give you examples, um, then we'll talk a little bit about when to refer, um, and that's it. So, hopefully you have your uh video on. If you were planning to just um listen in while you're driving or something, um, I apologize, you're probably not gonna get as much out of this um without being able to see the videos. So weakness and hypotonia, why it matters, um, there are many treatments available now that we didn't always have available to us, um, and early diagnosis means earlier treatment and usually a better outcome. Um, so specifically, you all know probably by now that we have treatment available for spinal muscular atrophy, um, which used to be a death sentence, at least for type one. Um, and we treat a positive newborn screen for spinal muscular atrophy like an emergency, um, in the neurology department. Um, so we ask you to call us or at least mark it as urgent if you're referring a child for a positive newborn screen. We also get notified by the state, by the way, um, but we appreciate over communication. Um, and then rarely the new word screen can falsely be negative, um, for SMA, and you can still treat those children. Um, we have, uh, clinical trials, um, and FDA approved treatments, uh, now for some types of muscular dystrophy. Um, and then we have enzyme replacement for Pompei disease, um, and there are a few other treatments as well. And so, um, now that we have treatments available, early diagnosis matters more than it used to. Um, later diagnosis means that usually a worse outcome or maybe they will miss the window and won't qualify for treatments that are dependent on age, um, which is really unfortunate. And then we all know that early diagnosis means um earlier intervention services, um, so like therapy support. Um, so I'm gonna start by talking about tone versus strength, um, and how are those different, um, because it's not as easy as it seems. So, tone is, um, something that you can evaluate at rest, um, with really no participation from the patient, just by passive manipulation of their body. Um, and then strength requires patient participation, um, so the patient has to activate. Um, in other words, tone is state dependent and strength is not state dependent. Um, the best example of this, um, and pardon me for being a little bit crude, but if you have ever been around or helped to take care of an inebriated person, Um, you will find that their tone will be low, they'll be limp, it'll be difficult if you are trying to carry them, it will be difficult, they'll feel really heavy, um, but their strength is intact. If they took a swing at you, they would be very strong. So that's an example, the best one that I have found, although not the most appropriate for the difference between tone and strength. Um, so tone can be affected by, um, being sleepy. Um, if you ever carried, uh, a soulent child, sleepy child, um, they feel heavier, um, because their tone is lower when they're sleeping. No So moving on, um, to the newborn exam, we'll um start by giving some examples of tone. Um, so head lag in the newborn. We all know what head lag is, then when we dial in on it, we don't always know what it is. Um, so I'm gonna show a video here of a normal newborn, um, And you'll see in this video, newborns typically have and they have headlines. The head will lag behind the shoulders. See the ear behind the level of the shoulder that child to sitting. And an incomplete head lag is normal in newborns. I'll watch it one more time. Great. Um, now I'm gonna show you an example of an abnormal head lag, um, low tone, low axial tone. Um, this child has, you'll see a complete head lag. So, his head lags behind his shoulders, but he really never Never picks it up, and the examiner has to lift it manually, otherwise it will just lay on the bed. One more time. You can also see that as he pulls the baby's arms, there's really no tension in the baby's arms. Um, so that tells you that the tone is low as well. So pearls for newborn head lag evaluation, um, you do have to make sure that the baby is sort of ready and prepared, um, make sure that they're awake, give them maybe a little warning tug on their hands and arms. Remember that incomplete head lag is normal and complete head lag is not, um, and that the baby should have some tension in their arms, um, if their tone is normal. And if you're in doubt, check it more than once. For head control in the newborn, um, so this newborn is now in the sitting position. And they said should bob around. Some people get tired. While. But he'll be able to hold it up. And I don't have an abnormal example for that. Uh, for vertical suspension, so this is, uh, holding the baby under the arms, um, with your hands around the chest. Um, the baby should be suspended in this position without slipping through your hands. Um, and if there's shoulder girdle weakness, then it'll be difficult to hold the baby. The baby will slip through. So here's a normal, healthy newborn. See that it's pretty easy for this examiner to hold this baby. Resting on his hands. Um, and then we'll look at an abnormal example. He's been getting him in the. Difficult his hands kind of slipping. Because there's not So um. So that baby would um would slip through his fingers if he hadn't. Um, so, pearls here, any slip through is abnormal. Um, think to yourself, is it hard to hold this baby? Um, and again, check it, check it more than once if you're in doubt. Uh, for ventral suspension or horizontal suspension. Um, so you wanna hold the baby prone with one hand, um, warn the parents before you do this, let them know what, what you're about to do cause the baby might spit up. um. You should see That OK. Yeah Your head should extend the back at times and we'll get tired. And, and he'll keep some tension in his arms. They don't just hang down. So Pretty feisty in this. That normal ventral suspension. It's an Doctor Langton, um. I think it might be the audio from the video cutting out your sound, but I'm pretty sure when you're talking and the video is playing, we can't hear your audio, so. OK. And you can't hear the video audio either. Right, that's, that's just silent, but it's also causing your audio to be silent. That's a shame. OK, all right, I'll try and um. I'll try and mute the video, um. Hopefully, you can hear me. OK, hopefully you can hear me now. Yes. OK. Well, hopefully the slides have spoken for themselves. Um, so this is a, a newborn, um, abnormal example of ventral suspension. You can see that this baby basically just hangs down over his hand, um, his arms just hang down, his head hangs down, his legs hang down, he doesn't lift his legs up to the neutral plane. You can see he kind of tries a little bit, um, and this mostly reflects tone, a little bit of strength. Yeah. So the pros for ventral suspension are, uh, warn the parents, let them know what you're doing. Um, the head should extend, the legs should activate up to the neutral plane, the arms should flex, um, the baby will fatigue intermittently, um, but they shouldn't be a limp needle in your hand. Uh, moving on to the infant exam, so we'll look at some of those same aspects. Um, so we'll go back again and look at head lag. Um, in a 3 month old and a 6 month old and what normal looks like for them. Um, so here is a normal 3 month old. So He has some tension in his arms. And then he could see that his ears still lag behind his shoulders. We'll look at that again. But his head didn't completely extend like that abnormal baby example we saw at the beginning, um, where that head really would have um hyperextended to the point of injury if the examiner hadn't picked it up. This baby picked his own, picked his own head up, um, with traction that was placed on his arms, he gets there. So that's a normal 3 month old. So the head still lags, um, and that's normal. And then here's a 6 month old. And you can see that he no longer has any head lag. Go back and replay. So traction on his arms, he leads with his head, actually. Um. And so head lag should be gone by 7 months, should be completely gone. I'll look one more time and just see that his ears are in front of his shoulders. He leads with his chin. Chin coming up first. And so, um, By 6 months or so, the ears should be in front of the shoulders, just like in this baby, if you drew a line through his shoulders, his ears would be in front of them as you pull him upright. Um, and I always check it, check it more than once, um. And make sure that the baby is ready. Well, moving on to the toddler exam. So, at this point, um, you can get a little bit fancier with your head lag exam, and what we typically do in the neural muscle clinic is we have the child lay so that their head um hangs off the end of the exam table. Um, this is, I didn't have a great picture of it. This is obviously an adult, um, but what you would do is have the child lay down on their back and you would support their head in your hands, um. And then you would ask the child to sit up. And you should see the chin tuck. Um, just like in that 6 month old baby, the chin tucks, and they lead with their head. Um, You can, um, to isolate that neck flexion response, you can put gentle pressure on the patient's shoulder, um, pushing down a little bit. Um, you should see the chin tuck, and any variation, um, this is a little bit harder cause I thought this was gonna be in person, um. And and then it got changed to video, but, um, so I'm, if you can see my video, if you see any activation of the platysma muscle in the neck without flexion of the head happening, that's abnormal. If you see the child roll their head to the side as they try to sit up, any head rolling to the side is abnormal. Um So they really should lead with the head, just like we saw in that 6 month old baby video. You can do the same thing in an older child, um. And then next we're gonna talk about Gower sign, which just like head lag is something that we all know what it is, but sometimes we don't know what it is, or we can miss it. Um. And so the Gower sign is the characteristic maneuver of um climbing up one's thighs while standing up, um, so like pushing off of the thighs with the hands or the elbows, um, and it means that there is proximal weakness. Um, it often starts with a patient rolling from supine to prone. So if you have them lying down on their back and you ask them to get up, they'll roll over onto their belly first, and then they'll get up as opposed to just sitting up. Um, because they have proximal weakness. And um, if you see that, after age 3, it's abnormal. Um, so a 3 year old should be able to just sit up from lying supine. Um, without rolling over onto their belly first. Um, so what we do in the neuro muscle clinic is we have the patients start by lying down flat on the floor, and we tell them on the count of 3, I want you to get up as fast as you can without grabbing on to anything. Um, any use of their hands on anything is abnormal beyond 18 months. Um, so grabbing onto furniture, pushing off the floor, pushing off of their legs with their hands is abnormal beyond 18 months. Um, these are some still shots of a normal 2.5 year old standing up. Um, so she's sitting on her bottom on the floor, um, they won't lie down, you can have them sit, but usually we have them lie down. Um, so she's on her bottom on the floor, and then tell her to get up, and you can see that she just puts her legs under her, she doesn't push off of anything, um, and then she's upright. I'm gonna show you a couple examples of a mild gower sign, cause I think everyone would be able to recognize um a severe gower, but it's the mild ones that can escape notice that um I think it's helpful to see examples. So they have this little boy trying to get up. And you can see he's pushing off of his foot, pushing off the floor, and one thigh there. I show that again. And just like with everything else, you can have them do it multiple times if you're not sure. Now for the second one. I'm gonna change screens that I'm sharing, hopefully. Hopefully you can see this. Give me a sec. OK. Hope you're seeing a different uh video now from Ry Children's Hospital. Yes. Right. So there's a few examples here of, uh, mild Gowers. Um, you see this child brings his knees together, displays his feet. Cause he has proximal weakness, so that's abnormal. Even though he's not really pushing off anything, this person has to do the butt up maneuver first. And then they lead with their buttocks up in the air. So that's also abnormal. You can see that they really would prefer to push off something with their hands there. Or if they stagger their feet. And then this kid, he's a great example, I think, this last kid here. Just a second. Um, this kid who pushes off his thigh with his forearm, real subtle, like, I show that again. That's a positive Gower. And that child tripods, so he pushes both his hands off the floor. So these are all examples of positive Gower. That I think anyone could easily miss. Um, especially this kid. So he's the one, he's the one to remember in particular. Um, that would be a great example of someone with Um, with Becker muscular dystrophy. Is that push off right there. You go back. PowerPoint now. Um, and then we also ask children to run, um, so we take, have them go out in the hallway and have them run down the hall, um, and, um, by age 2.5, um, They should be able to have a coordinated run. Um, they're no longer wide-based, but younger toddlers are. So I'll show the video of this little girl. So she squats and recovers really well. She also threw it overhand, which is advanced for her age. You have behavioral toe walking there, stoops and recover as well. Yeah, she runs there, she leans her head forward a little bit. Go back for a second. The video is stuck. OK that's a good No, it's not gonna cooperate. Um, what I was trying to point out was that as she runs, she leans, she leans into the run, so she leans forward, um. Children who are stiff and upright as they run, um, you can kind of imagine their arms are moving really fast, but their body's not really going anywhere. Um, it's also a sign of proximal weakness. We'll watch the end of this video, just a few more seconds. She's gonna get up now. She did push off just a tiny bit there with her hand, but um She's 2 1/2. Um, and then lastly, but not leastly, um, perhaps most importantly, reflexes, um, check them. The pearl is to check the reflexes, check them on normal healthy children who you're not worried about weakness and hypotonia for, so that when a parent asks you, um, or you're worried about a child, you remember how to do it because it's easy to forget, um. And really important, uh, if reflexes are increased, um, then this implies a central nervous system problem or more likely it's a normal healthy baby if their tone is normal, but the rest of your exam is normal. Sometimes reflexes, um, as we know, can be just more brisk in children, um, even a couple beats of clonus. Um, and then if they're decreased, that is helpful. Um, it helps you localize this as a peripheral problem, um, and I would argue that in a newborn, that helps you triage that this is probably something more urgent, um, because again, we have those treatable conditions that we don't wanna miss. Um, And so, To check the reflexes, um, in newborns, infants, and in young children, um, the patellers are the easiest and the most reliable. So if you're gonna pick one reflex to get good at, um, do patellers, just I would recommend just incorporate it on everybody's, um, your newborn exam and your annual exam. So he's gonna check this baby who's fortunately very relaxed and cooperative. It's not always that easy, obviously. And see how he does it multiple times. He doesn't just do it once and say, I think that was it. Um, he does it just a few times in a row and sees that a stereotype is the same every time. The reflex should be the same every time you apply the same amount of force. So he's checking the Achilles too, that's harder in babies cause they have the plantar grasp reflex. Um, he's doing biceps, which is Looks great, um, but is definitely more technically challenging, um, and not as reliable in our experience. I'm in the muscle clinic. And then tricep you don't usually get in newborns because they have so much flexor tone. Um, and then this is just a still shot of a, uh, an older baby, um, having the patellar reflexes checked. Um, obviously easier in a baby that's more cooperative, um, but anything you can get is helpful. Um, and then again, just practicing on healthy normal babies where you're not worried about it, um, helps you feel more confident when it's not there, um, in a patient with low muscle tone. Um, you can also check for clonus, that's helpful if it's present. Um, there's a couple beats of clonus that's actually um reassuring. If there's a lot, then it makes you worry about a central nervous system problem, but, um, if a baby has low muscle tone, um, and you think they're weak, um, and they have a couple beats of clonus, that's actually reassuring that it's probably not a neuromuscular, um, problem. It's probably a central nervous system. Um, and so just to review, um, why, why it matters, um, so we have time sensitive treatments now for a lot of our neuromuscular conditions, you could save a life, um. We talked about the difference between tone and strength. Um, we went through normal and abnormal newborn exam, um, we went through normal infant, um, and older child exams, um, we showed examples of a mild positive gower, um, not to be missed. Um, and, um, taught a new exam technique of um having the patient's head off the end of the exam table, um, and having them sit up from there and seeing does their head roll to the side, um, or does their platysma activate, um, without their neck flexing, both of those being um abnormal, um, and then to check reflexes, um. So when to uh refer, um, obviously if, if you think the reflexes are significantly increased, or if you think reflexes are not there, that's an indication for referral to neurology. Um, and you can mention that on your referral indication. Um, if there's any head lag still at 7 months, you should refer or if there's head lag that's not improving earlier than that, um, so trending it over time, it doesn't seem to be changing, it's not getting better. Um, We talked about the neckro and flama activation. Um, if, if they can't run right, um, they have an upright run where they move their arms really quickly, but they're not really going anywhere, um, or other parents are pointing out to the parents of the child, he, he, his run looks funny, his run looks weird. Um, and then any hint of a positive gower or modified positive gower, um, you should be able to rise from the floor without hands by 18 months. Um, sometimes it's helpful to have the patient cross their arms, across their chest, um, like that little girl in the video, you could have had her, um, cross her arms across her shoulders, um, so that she doesn't use her hands when she's getting up, um, if she's having trouble following directions. Um, and then remember the mild cases of um positive gower due to this. Um, and that's actually all I have. Um, so these are my acknowledgements. Most of these movies, um, were taken from, um, the University of Nebraska, uh, Doctor Paul Paul Larson, if you know Doctor Doug Larson in our child neurology department. Um, his dad and some of his colleagues, um, made these wonderful videos, um, and there are QR codes in here. You can link to this website and see a lot more examples of, um, normal and abnormal, um, exams. If you're interested. Um, again, a lot of our neurologists look at these every year because they're so helpful. I'm happy to take any questions or comments. Created by Presenters Erin L. Langton, MD Pediatric Neurology View full profile
