Chiari malformations, cerebellar tissue through the foramen magnum into the cervical canal, may clinically present in categories of pain-occipital/cervical (worsened with valsalva, cough, sneeze, or exertion), complications of syringomyelia (scoliosis, myelopathy), direct brainstem compression (e.g. nystagmus, strabismus, emesis, imbalance, auditory, swallowing/aspiration, and central apnea), as well as incidental.
Join Dr. Grabb and Transformational Pediatrics, as we discuss the relevant anatomy, discuss the pathophysiology of syrinx development, examine the different types of Chiari malformations and describe the classic clinical presentations for symptomatic Chiari 1 and 2 malformations.
Selected Podcast
Chiari Malformations – What to Know and When to Worry
Featured Speaker:
Learn more about Paul A. Grabb, MD
Paul A. Grabb, MD
Paul A. Grabb, MD, is the Section Chief of Neurosurgery at Children’s Mercy Kansas City; Associate Professor, Department of Neurosurgery, University of Kansas School of Medicine; Associate Professor of Surgery, University of Missouri-Kansas City School of Medicine. He received his medical degree from the University of Virginia School of Medicine and completed a residency in neurological surgery at the University of Pittsburgh Medical Center and The Children’s Hospital of Pittsburgh, in Pittsburgh, Pa. He completed a fellowship in Pediatric Neurosurgery at Children’s Hospital of Alabama, Birmingham, and is board certified by the American Board of Neurological Surgery and the American Board of Pediatric Neurological Surgery. He has special interests in neuroendoscopy for tumors, cysts, and hydrocephalus, brachial plexus injuries, spinal trauma, brain tumors and Chiari malformations.Learn more about Paul A. Grabb, MD
Transcription:
Chiari Malformations – What to Know and When to Worry
Dr. Michael Smith (Host): Today our topic is “Chiari Malformations: What to Know and When to Worry”. My guest is Dr. Paul Grabb. He’s the Section Chief of Neurosurgery at Children’s Mercy Kansas City. Dr. Grabb, welcome to the show.
Dr. Paul Grabb (Guest): Thank you.
Dr. Mike: So, why don’t we do this first for a lot of the general practitioners out there, family doctors who maybe don’t always see Chiari malformations, why don’t you first run through what are the different types, again, and what are some of the common presentations that children have with Chiari malformations.
Dr. Grabb: Okay, well, first to just define what a Chiari malformation is--just the name itself makes parents anxious and physicians anxious when they hear the word “malformation”. What I try to imply is that it’s not necessarily that the brain or a part of the brain is malformed in some way, but the way to think of it is that the container for that part of the brain, that cerebellum in the brainstem that we refer to as the posterior fossa, you can think of it the back-bottom part of your skull, for some reason didn’t grow large enough to accommodate the growth of the brain at that time. And, so, the brain itself just continues to grow, the cerebellum grows very rapidly early in infancy, and it just seeks out wherever there’s room. So, if the bone itself has not grown large enough, then it just continues to grow through the hole in the base of the skull called the “foramen magnum”, down into the spinal canal. In essence, when that brain grows through that hole down in into the spinal canal, that is what is then deemed a Chiari malformation. Now, there can be true malformations of the bone, the skull base itself that contribute to there not being enough room, but not always. Then this leads, again, to the same problem of there just not being enough room for the brain there. We do categorize them into different types. Certainly, the most common type that we see is the Type 1. That is where the cerebellar tonsils which, again, are a part of the cerebellum, are below the foramen magnum. People argue on a definition. Most people will say that they have to be at least 3 millimeters; some people say they have to be at least 5 millimeters down to “be a Chiari malformation Type 1.” Those that we deem Type 2 are, for the sake of argument, always associated with children with myelomeningocele, that the most significant type of spina bifida--so that’s its own little category on its own. Then we get fancy and have type 0s and Type 1 1/2s, and all that does is confuse parents and confuse other physicians. And so, I’ll leave those definitions for argument among pediatric neurosurgeons at that point.
Dr. Mike: And how common are the Chiari malformations?
Dr. Grabb: Well, now it’s really the almost unrestricted use of MRI for a child that sneezes two times in a row. It’s seems as though everyone gets in MRI at some point. And, so, they are quite common in our population. So, the incidence is going to be in the low single digits percentage-wise. The problem is that just because you “have a Chairi malformation” doesn’t mean that you have a problem or are going to develop a problem. So, commonly children will present to us with the diagnosis of Chiari malformation because it was picked up on a scan that was done because they had a concussion or because they had a seizure or because they had a bad migraine headache, all of which are not related at all to the Chiari malformation though the Chiari malformations can cause significant problems, and I categorize them into three broad categories for the families and for referring physicians. The first is pain but the pain is distinctly posterior at the occipital cervical junction and midline. So, you can think of it as the back of the head at the hairline, if that’s where they hurt. Classically, that pain tends to be intensified by things that raise the pressure in the head like coughing, Valsalva maneuvers, exertion, things like that. I think we pretty much are in agreement that a Chiari malformation doesn’t cause frontal or bi-temporal headaches. Now, can an occipital posterior head ache worse into a total global headache? Yes, to answer that question. But, generally, we’re looking for pain where the back, bottom part of the head. The other symptom that can occur as they can create a disturbance in the spinal fluid circulation so that spinal fluid actually begins to cavitate and accumulate within the spinal cord, and the name for that is “syringomyelia” or a “syrinx formation”, and it’s a really slow-motion injury of the spinal cord, and that can lead to a host of problems. Scoliosis, again, is a textbook presentation for a syrinx in a child with a Chiari malformation, but it can also cause motor deficits so the kids can come in weak, they can come in with balance and gait issues. It’s not going to cause incontinence or bowel problems until they’re virtually paralyzed in a wheelchair. So, a kid that’s not potty training is not going to be a way that a kid with a Chiari malformation or a syrinx would present. And then, finally, because of the tightness in the area where it should be, the craniocervical junction, that the spinal cord and brainstem surrounded by spinal fluid instead is impacted by brain tissue. And there may be in some folks, as we touched on earlier, an associated, an abnormality or an anomaly of the actually bony craniocervical junction whether it’s the skull base or the upper cervical spine. There can be compression of the neural elements at that level, and that can create a whole host of different problems. It can be eye movement difficulties, it can be swallowing issues to the point where children are aspirating. I've seen teenagers come in with the onset of unexplained chronic vomiting and weight loss. Again, the vomiting center for the brain is right back there. So, there can be a wide range of symptoms that these kids present with.
Dr. Mike: Okay. So, as you said, everybody’s getting MRIs today. We’re finding the Chiari malformation more and more because of that technology. So, as a physician, when do I worry? Are there some guidelines that you can lay out for us that will tell me, yeah, you need to go be seen immediately; we can watch you? What are some of those guidelines?
Dr. Grabb: Like I said, if they fall into the three broad categories of pain that we would blame on the Chiari malformation, that’s a reason to seek neurosurgical consultation. And then it’s a discussion about, well, how bad are you hurting? Are you missing school? Are you not enjoying life because of this or is this something that bugs you once a month and you take some ibuprofen and feel better? So, if the pain raises a red flag; any findings on examination, weakness, scoliosis, gait instability that would suggest a syrinx, would be a reason to seek consultation, and then we would then order further imaging of the spinal cord to look for changes in the spinal cord lower down. And, then, also, the more alarming brainstem findings of eye motions difficulties; swallowing difficulties. Again, in young children it may be that they’re aspirating, and then that could lead to asthma. So, a child that is, again, having feeding difficulties or eye motion difficulties, or swallowing difficulties, are going to be a red flag to have that addressed and seen by a neurosurgeon.
Dr. Mike: What’s the follow-up for a patient who’s having no symptoms?
Dr. Grabb: There’s not much role for repeat imaging unless you’re going to follow somebody that has a syrinx, has a cavitation within the spinal cord by the spinal fluid. And, so, really, it’s going to be clinical follow-up. Commonly, we’ll just see folks back on an annual basis and, obviously, you see them back sooner if any concerns develop but it’s unlikely that there’s going to be some emergency or acute change. So, we’re comfortable following those folks annually to the point where people go, “Hey, nothing’s happening. We’ll call you if we need you.” And, again, we customize it. There are, obviously, different families that are little more anxious than others and some want to be seen forever or seen more frequently. So, we just accommodate to that.
Dr. Mike: Okay, all right. Well, Dr. Grabb, this is fascinating information. I want to thank you for the work that you’re doing at Children’s Mercy, and thank you for coming on this show today.
Dr. Grabb: Sure. My pleasure.
Dr. Mike: Thank you. You’re listening to Transformational Pediatrics with Children’s Mercy Kansas City. For more information you can go to www.childrensmercy.org. That’s www.childrensmercy.org. I’m Dr. Mike Smith. Thanks for listening.
Chiari Malformations – What to Know and When to Worry
Dr. Michael Smith (Host): Today our topic is “Chiari Malformations: What to Know and When to Worry”. My guest is Dr. Paul Grabb. He’s the Section Chief of Neurosurgery at Children’s Mercy Kansas City. Dr. Grabb, welcome to the show.
Dr. Paul Grabb (Guest): Thank you.
Dr. Mike: So, why don’t we do this first for a lot of the general practitioners out there, family doctors who maybe don’t always see Chiari malformations, why don’t you first run through what are the different types, again, and what are some of the common presentations that children have with Chiari malformations.
Dr. Grabb: Okay, well, first to just define what a Chiari malformation is--just the name itself makes parents anxious and physicians anxious when they hear the word “malformation”. What I try to imply is that it’s not necessarily that the brain or a part of the brain is malformed in some way, but the way to think of it is that the container for that part of the brain, that cerebellum in the brainstem that we refer to as the posterior fossa, you can think of it the back-bottom part of your skull, for some reason didn’t grow large enough to accommodate the growth of the brain at that time. And, so, the brain itself just continues to grow, the cerebellum grows very rapidly early in infancy, and it just seeks out wherever there’s room. So, if the bone itself has not grown large enough, then it just continues to grow through the hole in the base of the skull called the “foramen magnum”, down into the spinal canal. In essence, when that brain grows through that hole down in into the spinal canal, that is what is then deemed a Chiari malformation. Now, there can be true malformations of the bone, the skull base itself that contribute to there not being enough room, but not always. Then this leads, again, to the same problem of there just not being enough room for the brain there. We do categorize them into different types. Certainly, the most common type that we see is the Type 1. That is where the cerebellar tonsils which, again, are a part of the cerebellum, are below the foramen magnum. People argue on a definition. Most people will say that they have to be at least 3 millimeters; some people say they have to be at least 5 millimeters down to “be a Chiari malformation Type 1.” Those that we deem Type 2 are, for the sake of argument, always associated with children with myelomeningocele, that the most significant type of spina bifida--so that’s its own little category on its own. Then we get fancy and have type 0s and Type 1 1/2s, and all that does is confuse parents and confuse other physicians. And so, I’ll leave those definitions for argument among pediatric neurosurgeons at that point.
Dr. Mike: And how common are the Chiari malformations?
Dr. Grabb: Well, now it’s really the almost unrestricted use of MRI for a child that sneezes two times in a row. It’s seems as though everyone gets in MRI at some point. And, so, they are quite common in our population. So, the incidence is going to be in the low single digits percentage-wise. The problem is that just because you “have a Chairi malformation” doesn’t mean that you have a problem or are going to develop a problem. So, commonly children will present to us with the diagnosis of Chiari malformation because it was picked up on a scan that was done because they had a concussion or because they had a seizure or because they had a bad migraine headache, all of which are not related at all to the Chiari malformation though the Chiari malformations can cause significant problems, and I categorize them into three broad categories for the families and for referring physicians. The first is pain but the pain is distinctly posterior at the occipital cervical junction and midline. So, you can think of it as the back of the head at the hairline, if that’s where they hurt. Classically, that pain tends to be intensified by things that raise the pressure in the head like coughing, Valsalva maneuvers, exertion, things like that. I think we pretty much are in agreement that a Chiari malformation doesn’t cause frontal or bi-temporal headaches. Now, can an occipital posterior head ache worse into a total global headache? Yes, to answer that question. But, generally, we’re looking for pain where the back, bottom part of the head. The other symptom that can occur as they can create a disturbance in the spinal fluid circulation so that spinal fluid actually begins to cavitate and accumulate within the spinal cord, and the name for that is “syringomyelia” or a “syrinx formation”, and it’s a really slow-motion injury of the spinal cord, and that can lead to a host of problems. Scoliosis, again, is a textbook presentation for a syrinx in a child with a Chiari malformation, but it can also cause motor deficits so the kids can come in weak, they can come in with balance and gait issues. It’s not going to cause incontinence or bowel problems until they’re virtually paralyzed in a wheelchair. So, a kid that’s not potty training is not going to be a way that a kid with a Chiari malformation or a syrinx would present. And then, finally, because of the tightness in the area where it should be, the craniocervical junction, that the spinal cord and brainstem surrounded by spinal fluid instead is impacted by brain tissue. And there may be in some folks, as we touched on earlier, an associated, an abnormality or an anomaly of the actually bony craniocervical junction whether it’s the skull base or the upper cervical spine. There can be compression of the neural elements at that level, and that can create a whole host of different problems. It can be eye movement difficulties, it can be swallowing issues to the point where children are aspirating. I've seen teenagers come in with the onset of unexplained chronic vomiting and weight loss. Again, the vomiting center for the brain is right back there. So, there can be a wide range of symptoms that these kids present with.
Dr. Mike: Okay. So, as you said, everybody’s getting MRIs today. We’re finding the Chiari malformation more and more because of that technology. So, as a physician, when do I worry? Are there some guidelines that you can lay out for us that will tell me, yeah, you need to go be seen immediately; we can watch you? What are some of those guidelines?
Dr. Grabb: Like I said, if they fall into the three broad categories of pain that we would blame on the Chiari malformation, that’s a reason to seek neurosurgical consultation. And then it’s a discussion about, well, how bad are you hurting? Are you missing school? Are you not enjoying life because of this or is this something that bugs you once a month and you take some ibuprofen and feel better? So, if the pain raises a red flag; any findings on examination, weakness, scoliosis, gait instability that would suggest a syrinx, would be a reason to seek consultation, and then we would then order further imaging of the spinal cord to look for changes in the spinal cord lower down. And, then, also, the more alarming brainstem findings of eye motions difficulties; swallowing difficulties. Again, in young children it may be that they’re aspirating, and then that could lead to asthma. So, a child that is, again, having feeding difficulties or eye motion difficulties, or swallowing difficulties, are going to be a red flag to have that addressed and seen by a neurosurgeon.
Dr. Mike: What’s the follow-up for a patient who’s having no symptoms?
Dr. Grabb: There’s not much role for repeat imaging unless you’re going to follow somebody that has a syrinx, has a cavitation within the spinal cord by the spinal fluid. And, so, really, it’s going to be clinical follow-up. Commonly, we’ll just see folks back on an annual basis and, obviously, you see them back sooner if any concerns develop but it’s unlikely that there’s going to be some emergency or acute change. So, we’re comfortable following those folks annually to the point where people go, “Hey, nothing’s happening. We’ll call you if we need you.” And, again, we customize it. There are, obviously, different families that are little more anxious than others and some want to be seen forever or seen more frequently. So, we just accommodate to that.
Dr. Mike: Okay, all right. Well, Dr. Grabb, this is fascinating information. I want to thank you for the work that you’re doing at Children’s Mercy, and thank you for coming on this show today.
Dr. Grabb: Sure. My pleasure.
Dr. Mike: Thank you. You’re listening to Transformational Pediatrics with Children’s Mercy Kansas City. For more information you can go to www.childrensmercy.org. That’s www.childrensmercy.org. I’m Dr. Mike Smith. Thanks for listening.