Moyamoya
What is Moyamoya?
Moyamoya disease is a cerebrovascular disorder that primarily affects the blood vessels in the brain, leading to restricted blood flow. The term "moyamoya" means "puff of smoke" in Japanese, which describes the appearance of the tiny, fragile blood vessels that form in an attempt to compensate for the blocked or narrowed major arteries. Eventually these fragile vessels will regress and the lack of blood flow to the brain will lead to strokes, if untreated.
What Causes Moyamoya in Children?
The exact cause of Moyamoya disease, especially in children, is not fully understood. However, research suggests that a combination of genetic and environmental factors may contribute to its development. Here are some potential factors that could play a role:
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Genetic Factors: There appears to be a genetic component to Moyamoya disease, as it can sometimes run in families. Mutations in certain genes have been linked to an increased risk of developing the condition. However, the specific genes involved, and their precise roles are still being studied.
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Autoimmune Factors: Some researchers believe that Moyamoya disease might have an autoimmune component, where the body's immune system mistakenly attacks the blood vessels in the brain. Autoimmune diseases occur when the immune system targets healthy tissues.
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Environmental Factors: While genetic factors play a significant role, environmental factors could also contribute to the development of Moyamoya disease. Some studies have suggested a potential association between viral infections and the onset of Moyamoya disease. Additionally, radiation has been shown to cause regression of brain normal vasculature, leading to a moyamoya like picture.
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Other Medical Conditions: Moyamoya syndrome can be associated with other medical conditions, such as neurofibromatosis type 1, Down syndrome, sickle cell disease, and certain autoimmune disorders. In these cases, the presence of these underlying conditions may increase the risk of developing Moyamoya disease.
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Blood Flow Regulation: It's believed that disruptions in the normal regulation of blood flow in the brain may contribute to the development of Moyamoya disease. The brain's response to reduced blood flow might involve the formation of the characteristic network of tiny blood vessels seen in Moyamoya patients.
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Hormonal Factors: Some researchers have explored the potential role of hormonal factors in the development of Moyamoya disease, particularly in pediatric cases. However, more research is needed to understand the precise mechanisms involved.
What Symptoms Might Moyamoya Causes in Children?
Moyamoya disease and Moyamoya syndrome can present with a variety of symptoms in children. The symptoms can vary in severity and may develop gradually or suddenly. Some of the common symptoms of Moyamoya disease in children include:
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Transient Ischemic Attacks (TIAs) and Strokes: Children with Moyamoya disease are at an increased risk of experiencing transient ischemic attacks (mini-strokes) or actual strokes. Symptoms of a TIA or stroke can include sudden weakness or paralysis on one side of the body, difficulty speaking, vision problems, and altered consciousness.
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Headaches: Severe and recurrent headaches are a common symptom, often accompanied by other neurological symptoms. These headaches may be due to decreased blood flow to certain areas of the brain.
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Seizures: Children with Moyamoya disease may experience seizures, which can manifest as convulsions, altered awareness, or repetitive movements.
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Weakness and Paralysis: Muscle weakness, particularly on one side of the body, can occur as a result of reduced blood flow to the brain regions that control movement.
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Language and Cognitive Difficulties: Moyamoya disease can impact cognitive function and language skills. Children may have difficulty with memory, attention, problem-solving, and language comprehension.
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Vision Problems: Visual disturbances can include blurred or double vision, partial loss of vision, or other visual perceptual issues.
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Developmental Delays: Children with Moyamoya disease might experience delays in achieving developmental milestones, such as walking, talking, and fine motor skills secondary to hypoxic events.
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Behavioral Changes: Irritability, mood swings, and other behavioral changes can be observed in children with Moyamoya disease, possibly due to disruptions in blood flow to the brain.
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Numbness or Tingling: Sensory symptoms, such as numbness or tingling in the limbs or face, may occur as a result of compromised blood flow.
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Unusual Movements: Children might exhibit abnormal movements or postures, such as dystonia or chorea, due to the impact of Moyamoya disease on the brain's motor control areas, after stroke.
It's important to note that the symptoms of Moyamoya disease can overlap with other neurological conditions, and not all children will experience the same set of symptoms. Prompt diagnosis and treatment are crucial to managing the condition and preventing complications. Early intervention can help improve outcomes and quality of life for children with Moyamoya disease.
What Treatments are Available for Moyamoya in Children?
Once your child has been diagnosed with Moyamoya, I (as a pediatric neurosurgeon in New York) will work with you, your child, and other medical professionals (e.g., pediatricians, neurologists, radiologist, neuro-endovascular surgeon, physical therapists, and occupational therapists) at Children's Hospital at Montefiore (CHAM) to formulate a customized treatment strategy tailored to your child’s needs. This customized treatment may utilize any one or a combination of the following interventions:
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Surgical Interventions: These surgical procedures are aimed at improving blood flow by rerouting blood vessels to supply the brain more effectively. They include techniques like pial synangiosis and encephalosynangiosis.
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Encephalo-myo-synangiosis (EMS): Similar to EDAS, EMS uses a graft of muscle tissue from the patient's temple region to encourage the development of collateral blood vessels.
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Indirect Bypass/ Encephaloduroarteriosynangiosis (EDAS) Surgery: In this approach, the surgeon uses a scalp blood vessel to create a new network of blood vessels on the surface of the brain, by placing the vessel in close proximity to the surface of the brain. This promotes increased blood flow to the brain, over a period of months.
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Direct Bypass Surgery: This surgical procedure involves creating a direct connection between a blood vessel in the scalp and a blood vessel on the surface of the brain. This bypass helps to restore blood flow from an area of the body that is not need it to the brain that has a reduce blood flow, in order to decrease the risk of stroke.
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Medications: Children with Moyamoya disease may be prescribed medications to help manage symptoms and reduce the risk of stroke. These can include antiplatelet agents or anticoagulants to prevent blood clots from forming.
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Rehabilitation Therapy: Physical therapy, occupational therapy, and speech therapy, can help children recover or improve their motor skills, coordination, and language abilities after surgery or a stroke.
Regular follow-up appointments and imaging studies are essential to monitor the progression of the disease and the effectiveness of the chosen treatment strategy. Early intervention and ongoing management are key to optimizing outcomes and minimizing the risk of complications in children with Moyamoya disease.
