Moyamoya Disease

What Is Moyamoya Disease? Moyamoya disease is a rare, progressive cerebrovascular disorder in which the main arteries supplying blood to the brain—particularly the internal carotid arteries—become narrowed or blocked. As blood flow decreases, the brain compensates by forming a network of small, fragile blood vessels at its base to maintain circulation. These abnormal collateral vessels are prone to bleeding and clotting, significantly increasing the risk of recurrent strokes and transient ischaemic attacks (TIAs). The term “moyamoya”, meaning “puff of smoke” in Japanese, refers to the characteristic appearance of these tangled vessels seen on cerebral angiography. Although moyamoya disease is more commonly diagnosed in children, it can also affect adults, often presenting with different symptoms and complications. Types of Moyamoya Disease Idiopathic Moyamoya Disease This is the primary form, with no identifiable underlying cause. Secondary Moyamoya Syndrome This form develops in association with other medical conditions, including: Neurofibromatosis Down syndrome Previous radiation therapy to the head Certain genetic or systemic disorders Symptoms of Moyamoya Disease Symptoms vary depending on the patient’s age and the severity of arterial narrowing. Common signs and symptoms include: Sudden weakness or paralysis, often affecting one side of the body Recurrent transient ischaemic attacks (TIAs) or strokes Severe or persistent headaches Seizures (more common in children) Cognitive impairment, including memory and learning difficulties Visual disturbances or sudden vision loss Speech problems, such as difficulty speaking or understanding language Involuntary movements, including chorea or dystonia When to Seek Emergency Medical Care Immediate medical attention is critical if stroke symptoms are suspected. Remember FAST: F – Face: Facial drooping when smiling A – Arms: Weakness when raising one or both arms S – Speech: Slurred speech or difficulty understanding T – Time: Call emergency services immediately Prompt treatment can be life-saving and reduce long-term disability. Causes of Moyamoya Disease The exact cause of moyamoya disease remains unknown, but several contributing factors have been identified: Genetic predisposition: The condition may run in families and is more common among individuals of East Asian descent Autoimmune conditions: Diseases such as lupus may be associated Environmental factors: Previous radiation therapy to the brain increases risk Complications and Related Conditions Progressive narrowing of cerebral blood vessels can lead to serious neurological complications, including: Recurrent TIAs Ischaemic stroke (cerebral infarction) Haemorrhagic stroke Developmental delays and learning difficulties in children Permanent weakness or paralysis Speech and language disorders Seizure disorders Emotional and behavioural changes, including anxiety, depression, and personality changes Can Moyamoya Disease Be Prevented? Currently, there is no known method to prevent moyamoya disease, as its underlying cause is not fully understood. However, proactive management can reduce complications: Regular neurological evaluations for early diagnosis Genetic counselling for families with a known history Maintaining vascular health through: Balanced nutrition Regular physical activity Avoidance of smoking Early detection and appropriate medical or surgical management are key to improving long-term outcomes.