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. All right, we will go ahead and get started. Um We wanna say good evening to all of you and thank you for joining the speaker series tonight. Um We have Doctor Linton who specializes in pediatric neurology and today she's speaking on the subject of muscle weakness and hypotonia for the general pediatrician. Uh We would love to encourage anyone who has questions to unmute during and um ask those questions and feel free to turn on your camera as well if you'd like and to mingle with everyone. Um We wanna make this feel just like it was before I know we're at virtually now, but we wanna make sure that we leave room for mingling as well tonight. Um We'll go ahead and give Doctor Linton our full attention. Great. Thank you so much, Madison. 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 Aaron Langton. I'm an assistant professor in neurology here at Wash U. 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 the clinical footprint that bans 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 and 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 And 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 with this 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 S MA 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 pompeii 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 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 somnolent 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 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, move that child up to sitting and its incomplete head lag is normal in newborns. I'll watch it one more time right. 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 had 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 new one is now outside in a sitting position and the 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. Uh It's pretty easy for this examiner to hold this baby resting on his hands. Um And we'll look at an abnormal example. He's been getting him in the system difficult, his hands slipping because there's not for them. 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 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 because the baby might spit up. Um You should see six. Ok. Yeah, please. Your head should extend the line the back at times and you get tired and, and he'll keep some tension in his arms. They don't just hang down. So I just pretty feisty and sh that's normal. Even suspension is an, a 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 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. Ok. Yeah. So the Pearl's prevental 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 three month old and a six month old and what normal looks like for them. Um So here is a normal three month old. So he has some tension in his arms and then you 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 was um hyper extended 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 three month old. So the head still lags. Um and that's normal and then here's a six 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 seven 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 six months or so the ears should be in front of the shoulders, just like in this baby. If you threw a line through his shoulders, his ears would be in front of them as you pull him up. Right. Um, and I always check it, check it more than once, um, and make sure that the baby is ready 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 six 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 because I thought this was gonna be in person. Um And, and it got changed to video. But uh so I'm, if you could 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 six month old baby video and 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 can 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 three, it's abnormal. Um So a three 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 neural muscle clinic is we have the patients start by lying down flat on the floor and we tell them on the count of three. 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 If 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 because 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 and show that again and just like with everything else, you can have them do it multiple times if you're not sure. No, but the second one, I'm gonna change screens that I'm sharing. Hopefully, hopefully you can see this. Give me a sec. OK. Hopefully you're seeing a different uh video now from Rady Children's Hospital. Yes. Right. So there's a few examples here. Uh mild gowers. Um So you see this child brings his knees together, displays his feet because 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 you 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 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, but 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 just that push off right there. Let me go back California 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 coordinate run. Um, they're no longer wide based, but younger toddlers are. So I'll show a video of this little girl. So she squats and recovers really well. She also threw it overhand, which is advanced for her age, 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. I think that's ok. No, it's not gonna cooper. 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 is not really going anywhere. Um It's also a sign of proximal weakness. I'll just 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 2.5. 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 young Children, um the patellas are the easiest and the most reliable. So if you're gonna pick one reflex to get good at um do patellar just in, 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 co-operative and you don't know, is 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 the stereotype is the same every time the reflex should be the same every time you apply the same amount of force, he's checking achilles too. That's harder in babies because they have the plantar grasp reflex. Um and he's doing bicep, which is looks great. Um But it is definitely more technically challenging um and not as reliable in our experience um in and out also 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 cooper. Um but anything you can get is helpful. Um And then again, just practicing unhealthy 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 of pieces 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 of pieces of clonus that's actually reassuring that it's probably not a neuromuscular um problem. It's probably a central nervous system. A RT. 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 seven months, you should refer or if there's head lag that's not improving earlier than that. Um So trending it over time, this doesn't seem to be changing, it's not getting better. Um We talked about the neck roll and plasma 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. Hey, 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 a 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 Acknowledgments. 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. Well, thank you for speaking for us this evening. Um Are, are you ok if I send the slides out to those who attended? Sure. Let me, um do you want me to email you the updated slides or upload them Yeah, that'd be great. Um, either one works. Sounds good. And then for anyone who has questions, feel free to write them in the chat or unmute, um, if you'd like to chat before we go. Hi, this is Paula. I, I have a question. You mentioned several times that there are treatments now and could you just talk about those for a little bit? Yeah, absolutely. Um, so most of what I'm talking about, uh for new treatments is gene therapy. Um So for spinal muscular atrophy, um there are a variety of different types of gene therapy available um that replace um either either replace the SMN one gene that's missing or um boost or augment the transcription of SMN two, which is um sort of a copy of SMN one gene that's missing in our genome um that's usually inactive. And so um those are um the first one which, which replaces SMN one is a one time IV treatment. Um that is FDA approved and given before age two, it's called zensa. Um And that's most of what our families with S MA that's newborn screen identified are opting for, is that one time IV treatment called Zolgensma? Um And we give that within the first few weeks of life um as soon as we can get insurance approval for it. Um and then there are a couple of other types of gene therapy for S MA. Um and then for uh muscular dystrophy. Um So, for Duchenne Muscular dystrophy, there's an FDA approved treatment called Alevis um Elev ID Ys. And it's basically a shortened version of um the DMG um gene that is um administered intravenously and it doesn't work exactly the same as the D MD gene does, but it, it makes Duchenne into Becker basically. And so, um that is better, it's obviously not a cure. Um and it's not as good as the S MA gene therapy is, which is a miracle um That basically makes Duchin into better and that is FDA approved up to age six years. So once a child is six, they are no longer eligible um for that FDA approved um treatment as in their insurance company won't pay for it. Um It's exorbitantly expensive and so they may be a candidate for clinical trials beyond that. Um But the availability of those clinical trials is more sporadic. Um and then there are emerging treatments for Becker as well that um we actually have active clinical trials for at um was U at the moment um that involve uh uh mycin mycin activators or inhibitors, I can't remember off the top of my head. Um So those are some of the treatments that are newer and available. Um There's usually new clinical trials going on all the time. Um We have a huge clinical trials unit in the was U pediatric neuromuscular section. Thanks for your question. Sala looks like we have another one in the chat. Oh, ok. Um So for S ma after six year old is gene therapy helpful. Um Good question. So um the six year old age I was referring to was for the 11 for the Duchenne treatment. Um and the efficacy of that treatment is still, even though it's FDA approved the full efficacy in terms of long term is still being evaluated. Um The study evaluating the Duchenne treatment missed its primary end point um but did improved, improves um patient scores on some functional tests like time to walk a certain number of meters and things like that. Um For S MA treatment, um gene therapy is still helpful after six years old, but it's not, it's better to give it early. Um The problem in S MA is that the SMN one gene, um survival motor neuron gene isn't there or doesn't work and you need that gene for the motor neurons to survive as the name implies survival, motor neuron gene. So, without that gene, um the motor neurons start to die. Um And so the longer you wait, you say like the time is neurons and that's why we treat it like an emergency. Um but some treatment is better than no treatment. There are studies looking at adults with S MA um the more mild types and they were treated with the original gene therapy nin ursin. Um and they still had improvement, functional improvement um in studies and so it is still helpful. After six years old, it's helpful in older patients too. Thanks for your question, other questions or comments. Well, if that is all the questions for tonight, we wanna thank you very much. This was Doctor Langton S first time speaking for, for us. So give her a round of applause. Um We're very thankful for your time and for everyone joining us and supporting early Birds tonight. Um Next month or not Early Birds. This is speaker series. Um, next month, our speaker series topic um will be on adolescent medicine about how, what's next for marijuana and teens since it has been legalized. So we'll be back on February 27th. Great. Thanks everyone for coming. Thanks for having me. Um As always, if you ever have a question, you're worried about a child. Um And you're not sure how to triage your referral. Um You're always welcome to call us. Um and it actually makes a great opportunity for teaching our consult fellow. Um when those questions come up from primary care providers. So, thanks so much. Perfect. Thank you. Good night everyone. Thank you. Created by Presenters Erin L. Langton, MD Pediatric Neurology View full profile
