Moyamoya is a disease of abnormal blood vessels in the brain that can occur in children. It leads to narrowing and blood clot formation that prevents the brain from getting enough blood. Without treatment, Moyamoya can cause strokes or bleeding into the brain.
St. Louis Children's Hospital has a multidisciplinary team of pediatric neurosurgeons, neurologists, pediatricians, neuroradiologists, anesthesiologists, and physicians who work together to protect the brains and development of children with Moyamoya.
Joining the show to discuss the Moyamoya program at St. Louis Children's Hospital and when to refer, is Jennifer Strahle MD. She is a Washington University pediatric neurosurgeon at St. Louis Children's Hospital.
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Understanding Moymoya Disease in Children
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Learn more about Jennifer Strahle, MD
Jennifer Strahle, MD
Jennifer Strahle, MD is a Washington University pediatric neurosurgeon at St. Louis Children’s Hospital.Learn more about Jennifer Strahle, MD
Transcription:
Understanding Moymoya Disease in Children
Melanie Cole (Host): Today’s topic is moyamoya disease which is a rare progressive cerebrovascular disorder caused by blocked arteries at the base of the brain. My guest is Dr. Jennifer Strahle. She’s a Washington University Pediatric Neurosurgeon at St Louis Children’s Hospital. Welcome to the show Dr. Strahle. So, explain a little bit about moyamoya and do we know what causes it?
Dr. Jennifer Strahle, MD (Guest): Okay, thanks for having me today. Moyamoya is a disease or syndrome that occurs when the arteries at the base of the brain, like you mentioned, the distal internal cerebral arteries become occluded and when that happens, there can be stroke and or ischemia in the brain.
Melanie: Does it generally occur on its own or is it a comorbidity along with other diseases maybe Down syndrome or sickle cell? Is it something people would on the lookout for if a child has one of these other conditions?
Dr. Strahle: That’s a really good question. So, there are two types of moyamoya. Moyamoya disease occurs in the absence of any other syndrome. So, it is considered sort of idiopathic and occurs without any associated predisposition. Moyamoya syndrome occurs in the setting of either unilateral disease or disease on one side of the brain or in the setting of an associated condition and like you mentioned, patients who have sickle cell disease, neurofibromatosis I, Down syndrome, patients who have a history of cranial irradiation; those are patients that are at risk for developing moyamoya syndrome. There are also more rare conditions such as congenital heart disease that also predisposes to moyamoya syndrome.
Melanie: So, would a pediatrician be aware of this possibility and what should they be on the lookout for and parents as well? Are there some symptoms? What’s the clinical presentation?
Dr. Strahle: So, although moyamoya syndrome or disease is not very common; it’s more of a rare disease, it does – it is responsible for up to 6% of all childhood strokes. So, any child that is displaying signs of either a TIA so transient ischemic attack, that would be symptoms of ischemia or sort of transient stroke, anyone who displays those findings should be referred for further evaluation. And as part of that evaluation, usually an MRI is obtained. An MRI would show evidence of prior ischemia, but there are also other changes within the vessels that can be seen with an MRA which in an MRI that looks specifically at the blood vessels in the brain.
Melanie: So, if a child does have a TIA or something that really freaks a parent out and they have called their pediatrician, is this then emergent and then you as a neurosurgeon come in and you are the specialist now that will take over the situation?
Dr. Strahle: Well, there are many different reasons why a child could have a stroke. So, this is really just one of the many different reasons that could cause a stroke. Anyone who is having acute or new symptoms should be referred immediately in an urgent fashion to the emergency room if they are having acute symptoms of a stroke. Much more frequently, children will present with headaches, seizures, more chronic symptoms and a lot of kids actually who are the number of conditions that I mentioned are at risk for having moyamoya can have actually have silent stroke or findings on their MRI. So, there are sort of two pathways by which someone would present to the care of either our stroke neurology team and or neurosurgery. One would be the acute pathway where they are having acute symptoms of stroke and that would be going to the emergency room, calling 911 and getting evaluated immediately and then there is a second pathway for kids that are presenting in a more chronic fashion with chronic repeated symptoms.
Melanie: So, do you treat prophylactically if you feel that this child has any of the risk factors that you have mentioned and then if you or if you don’t, what would be the corresponding treatment if you suspect this is going on?
Dr. Strahle: Okay. So, another very good question. So, there are, like I mentioned previously, there are some kids at risk for having moyamoya that have what we call silent strokes or evidence of prior strokes on an MRI in conjunction with moyamoya. So moyamoya, the term moyamoya actually means puff of smoke in Japanese and that is term for collateral vessels that are formed in the setting of occlusion of the intracranial arteries. And when we see the moyamoya arteriopathy or findings of the moyamoya vasculature either on MRI or on formal catheter angiography; even if that patient has not had a clinical stroke, they are a candidate for surgical treatment. So, the medical treatment for moyamoya in all kids whether or not they have surgery are usually placed on aspirin, unless there is a contraindication. If there are prominent findings of moyamoya vasculature and stenosis of the intracranial arteries; then we do treat patients prophylactically to prevent further strokes. So, in one large study in children, patients with moyamoya, either moyamoya disease or moyamoya syndrome; their rate of strokes was about almost 70% before surgery. Surgical treatment of – and I will get into that in a second, I can explain in more detail surgical treatment decreased the risk of stroke to less than 10% after surgery.
Melanie: So, get into the surgical intervention for us and what would be involved if they do have stenosis that you have noticed or any of that.
Dr. Strahle: So, if there is a patient that is a candidate for surgery; for whatever reason, if they sort of end up in that category; there are two ways to address moyamoya. It’s either through direct revascularization or indirect revascularization. So, one of the hallmarks of moyamoya is that it is restricted to the intracranial vasculature, meaning that the arteries external to the brain, specifically the external carotid artery system are not affected. So, in direct revascularization treatment, usually the superficial temporal artery is used and would be directly anastomosed to one of the intracranial arteries, typically the middle cerebral artery. In the setting of an indirect revascularization; either the superficial temporal artery or muscle or in some cases just the dura which is covering of the brain itself; one of those three are used to provide an indirect revascularization and what that means is that there are vessels from those tissues will then indirectly anastomose with cortical and intracranial vessels. So, in pediatric neurosurgery, the majority of patients respond very well to an indirect revascularization where you take the superficial temporal artery and lay it on the brain and suture it to the pia which is a very thin covering right on the cortical surface.
Melanie: So, tell us about some of the new advancements or technology being done to improve to treatment or outcomes, the areas of innovation for moyamoya disease.
Dr. Strahle: So, here, we have a very large population – here in St. Louis, we have a very large population of sickle cell patients and there is a lot of innovation and diagnostic related innovation in this group of patients and also specifically related to trying to identify those sickle cell patients who are at risk for having strokes and understanding are there other imaging modalities to help screen these patients better and identify patients who are at risk for stroke. So, Dr. Holbert who is the director of our sickle cell program here, works with our sickle cell patients and trying to understand are there even more advanced either imaging modalities or criteria that we can use to better identify who is at risk for having strokes, particularly silent strokes in this population. And then we have a pediatric stroke neurology team led by Dr. Gilliams and she also specifically looks at more advanced imaging techniques to understand which of our pediatric patients are at risk for stroke and who would be best treated with either medial therapy or surgical revascularization.
Melanie: So, in summary, Dr. Strahle, tell other physicians what you would like them to know about moyamoya disease, when to refer, what to be on the lookout for and what the referring physician can expect from your team in so far as communication.
Dr. Strahle: So, we have a great team here at St. Louis Children’s Hospital and Washington University that includes both – both myself and our adult vascular team including Dr. Greg Zipfel. We work in conjunction with Dr. Gilliams who is our stroke neurologist as well as for instance in our sickle cell population, Dr. Holbert. So, we have a large multidisciplinary team both from a nonsurgical treatment side as well a surgical treatment side and then our endovascular team which includes both the endovascular neurosurgeon Dr. Osman as well as our endovascular radiology team. so, we have a very large team here. So, when someone is referred, they are usually referred as – from the pediatric side to myself and Dr. Gilliams and then from there we make recommendations in terms of initial diagnostic workup in terms of imaging and then from there make treatment recommendations and we work as a multidisciplinary team.
Melanie: Thank you so much. What an interesting topic Dr. Strahle. Thank you for being with us today. A physician can refer a patient by calling Children’s direct physician access line at 1-800-678-HELP, that’s 1-800-678-4357. You’re listening to Radio Rounds with St. Louis Children’s Hospital. For more information on resources available at St. Louis Children’s Hospital you can go to www.stlouischildrens.org, that’s www.stlouischildrens.org. This is Melanie Cole. Thanks so much for listening.
Understanding Moymoya Disease in Children
Melanie Cole (Host): Today’s topic is moyamoya disease which is a rare progressive cerebrovascular disorder caused by blocked arteries at the base of the brain. My guest is Dr. Jennifer Strahle. She’s a Washington University Pediatric Neurosurgeon at St Louis Children’s Hospital. Welcome to the show Dr. Strahle. So, explain a little bit about moyamoya and do we know what causes it?
Dr. Jennifer Strahle, MD (Guest): Okay, thanks for having me today. Moyamoya is a disease or syndrome that occurs when the arteries at the base of the brain, like you mentioned, the distal internal cerebral arteries become occluded and when that happens, there can be stroke and or ischemia in the brain.
Melanie: Does it generally occur on its own or is it a comorbidity along with other diseases maybe Down syndrome or sickle cell? Is it something people would on the lookout for if a child has one of these other conditions?
Dr. Strahle: That’s a really good question. So, there are two types of moyamoya. Moyamoya disease occurs in the absence of any other syndrome. So, it is considered sort of idiopathic and occurs without any associated predisposition. Moyamoya syndrome occurs in the setting of either unilateral disease or disease on one side of the brain or in the setting of an associated condition and like you mentioned, patients who have sickle cell disease, neurofibromatosis I, Down syndrome, patients who have a history of cranial irradiation; those are patients that are at risk for developing moyamoya syndrome. There are also more rare conditions such as congenital heart disease that also predisposes to moyamoya syndrome.
Melanie: So, would a pediatrician be aware of this possibility and what should they be on the lookout for and parents as well? Are there some symptoms? What’s the clinical presentation?
Dr. Strahle: So, although moyamoya syndrome or disease is not very common; it’s more of a rare disease, it does – it is responsible for up to 6% of all childhood strokes. So, any child that is displaying signs of either a TIA so transient ischemic attack, that would be symptoms of ischemia or sort of transient stroke, anyone who displays those findings should be referred for further evaluation. And as part of that evaluation, usually an MRI is obtained. An MRI would show evidence of prior ischemia, but there are also other changes within the vessels that can be seen with an MRA which in an MRI that looks specifically at the blood vessels in the brain.
Melanie: So, if a child does have a TIA or something that really freaks a parent out and they have called their pediatrician, is this then emergent and then you as a neurosurgeon come in and you are the specialist now that will take over the situation?
Dr. Strahle: Well, there are many different reasons why a child could have a stroke. So, this is really just one of the many different reasons that could cause a stroke. Anyone who is having acute or new symptoms should be referred immediately in an urgent fashion to the emergency room if they are having acute symptoms of a stroke. Much more frequently, children will present with headaches, seizures, more chronic symptoms and a lot of kids actually who are the number of conditions that I mentioned are at risk for having moyamoya can have actually have silent stroke or findings on their MRI. So, there are sort of two pathways by which someone would present to the care of either our stroke neurology team and or neurosurgery. One would be the acute pathway where they are having acute symptoms of stroke and that would be going to the emergency room, calling 911 and getting evaluated immediately and then there is a second pathway for kids that are presenting in a more chronic fashion with chronic repeated symptoms.
Melanie: So, do you treat prophylactically if you feel that this child has any of the risk factors that you have mentioned and then if you or if you don’t, what would be the corresponding treatment if you suspect this is going on?
Dr. Strahle: Okay. So, another very good question. So, there are, like I mentioned previously, there are some kids at risk for having moyamoya that have what we call silent strokes or evidence of prior strokes on an MRI in conjunction with moyamoya. So moyamoya, the term moyamoya actually means puff of smoke in Japanese and that is term for collateral vessels that are formed in the setting of occlusion of the intracranial arteries. And when we see the moyamoya arteriopathy or findings of the moyamoya vasculature either on MRI or on formal catheter angiography; even if that patient has not had a clinical stroke, they are a candidate for surgical treatment. So, the medical treatment for moyamoya in all kids whether or not they have surgery are usually placed on aspirin, unless there is a contraindication. If there are prominent findings of moyamoya vasculature and stenosis of the intracranial arteries; then we do treat patients prophylactically to prevent further strokes. So, in one large study in children, patients with moyamoya, either moyamoya disease or moyamoya syndrome; their rate of strokes was about almost 70% before surgery. Surgical treatment of – and I will get into that in a second, I can explain in more detail surgical treatment decreased the risk of stroke to less than 10% after surgery.
Melanie: So, get into the surgical intervention for us and what would be involved if they do have stenosis that you have noticed or any of that.
Dr. Strahle: So, if there is a patient that is a candidate for surgery; for whatever reason, if they sort of end up in that category; there are two ways to address moyamoya. It’s either through direct revascularization or indirect revascularization. So, one of the hallmarks of moyamoya is that it is restricted to the intracranial vasculature, meaning that the arteries external to the brain, specifically the external carotid artery system are not affected. So, in direct revascularization treatment, usually the superficial temporal artery is used and would be directly anastomosed to one of the intracranial arteries, typically the middle cerebral artery. In the setting of an indirect revascularization; either the superficial temporal artery or muscle or in some cases just the dura which is covering of the brain itself; one of those three are used to provide an indirect revascularization and what that means is that there are vessels from those tissues will then indirectly anastomose with cortical and intracranial vessels. So, in pediatric neurosurgery, the majority of patients respond very well to an indirect revascularization where you take the superficial temporal artery and lay it on the brain and suture it to the pia which is a very thin covering right on the cortical surface.
Melanie: So, tell us about some of the new advancements or technology being done to improve to treatment or outcomes, the areas of innovation for moyamoya disease.
Dr. Strahle: So, here, we have a very large population – here in St. Louis, we have a very large population of sickle cell patients and there is a lot of innovation and diagnostic related innovation in this group of patients and also specifically related to trying to identify those sickle cell patients who are at risk for having strokes and understanding are there other imaging modalities to help screen these patients better and identify patients who are at risk for stroke. So, Dr. Holbert who is the director of our sickle cell program here, works with our sickle cell patients and trying to understand are there even more advanced either imaging modalities or criteria that we can use to better identify who is at risk for having strokes, particularly silent strokes in this population. And then we have a pediatric stroke neurology team led by Dr. Gilliams and she also specifically looks at more advanced imaging techniques to understand which of our pediatric patients are at risk for stroke and who would be best treated with either medial therapy or surgical revascularization.
Melanie: So, in summary, Dr. Strahle, tell other physicians what you would like them to know about moyamoya disease, when to refer, what to be on the lookout for and what the referring physician can expect from your team in so far as communication.
Dr. Strahle: So, we have a great team here at St. Louis Children’s Hospital and Washington University that includes both – both myself and our adult vascular team including Dr. Greg Zipfel. We work in conjunction with Dr. Gilliams who is our stroke neurologist as well as for instance in our sickle cell population, Dr. Holbert. So, we have a large multidisciplinary team both from a nonsurgical treatment side as well a surgical treatment side and then our endovascular team which includes both the endovascular neurosurgeon Dr. Osman as well as our endovascular radiology team. so, we have a very large team here. So, when someone is referred, they are usually referred as – from the pediatric side to myself and Dr. Gilliams and then from there we make recommendations in terms of initial diagnostic workup in terms of imaging and then from there make treatment recommendations and we work as a multidisciplinary team.
Melanie: Thank you so much. What an interesting topic Dr. Strahle. Thank you for being with us today. A physician can refer a patient by calling Children’s direct physician access line at 1-800-678-HELP, that’s 1-800-678-4357. You’re listening to Radio Rounds with St. Louis Children’s Hospital. For more information on resources available at St. Louis Children’s Hospital you can go to www.stlouischildrens.org, that’s www.stlouischildrens.org. This is Melanie Cole. Thanks so much for listening.