Moyamoya Disease: Understanding Symptoms Across Age Groups

Moyamoya disease is a rare, progressive cerebrovascular disorder characterized by the narrowing or complete blockage of the internal carotid arteries and the terminal portions of the anterior and middle cerebral arteries—the primary blood vessels supplying the brain. As these major arteries become obstructed, the brain compensates by forming a fragile network of tiny collateral blood vessels at the base of the skull. These abnormal vessels, which appear as a "puff of smoke" on angiograms (hence the name "moyamoya," Japanese for "puff of smoke"), attempt to reroute blood flow but are prone to rupture or clotting. This vascular instability leads to a wide range of neurological symptoms that vary significantly depending on the patient's age.

Symptoms in Children: Predominantly Ischemic Manifestations

In pediatric patients, moyamoya disease most commonly presents with ischemic symptoms caused by insufficient blood flow to critical areas of the developing brain. The most frequent signs include transient ischemic attacks (TIAs), often referred to as "mini-strokes." These episodes may manifest as sudden weakness or numbness on one side of the body—known medically as hemiparesis or hemisensory disturbance.

Children may also experience speech difficulties, vision problems, or involuntary movements. Seizures are another common feature, occurring in up to 50% of affected children. Because the brain relies on an inefficient network of small collateral vessels rather than robust primary arteries, chronic oxygen deprivation can impair cognitive development. Over time, this may result in learning disabilities, developmental delays, or behavioral and psychiatric symptoms such as attention deficits or mood disorders.

Parents might notice their child suddenly collapsing during physical activity or hyperventilation—a hallmark clue in diagnosing pediatric moyamoya. Early recognition is crucial, as repeated ischemic events can lead to permanent brain damage if left untreated.

Symptoms in Adults: Increased Risk of Hemorrhagic Events

While children typically suffer from ischemia, adults with moyamoya disease are more likely to experience hemorrhagic complications. The delicate collateral vessels formed in response to arterial blockage are structurally weak and prone to leaking or rupturing. This can lead to intracerebral hemorrhage (bleeding within the brain tissue) or subarachnoid hemorrhage (bleeding into the space surrounding the brain).

Common Hemorrhagic Presentations in Adults

Sudden, severe headaches—often described as "the worst headache of my life"—are typical warning signs. Neurological deficits such as paralysis or sensory loss on one side of the body (hemiplegia or hemianesthesia), difficulty speaking (aphasia), or altered consciousness including confusion or coma may follow. These symptoms mimic those of aneurysmal bleeding or other stroke types, making accurate diagnosis essential.

Interestingly, some adult patients may still present with ischemic symptoms, especially if they have underlying conditions like hypertension or diabetes that further compromise cerebral circulation. Thus, there is a clinical overlap between age groups, though the dominant presentation tends to shift from ischemia in youth to hemorrhage in adulthood.

Diagnosis and Importance of Imaging

Given the variable and often non-specific nature of symptoms, diagnosing moyamoya disease requires advanced neuroimaging techniques. Magnetic resonance imaging (MRI) combined with magnetic resonance angiography (MRA) is typically the first-line diagnostic tool, revealing both brain infarcts and the characteristic vascular changes. Digital subtraction angiography (DSA), while invasive, remains the gold standard for confirming the diagnosis due to its high resolution of cerebral vasculature.

In summary, moyamoya disease is a complex cerebrovascular condition with distinct clinical patterns across age groups. Children primarily exhibit ischemic symptoms related to poor perfusion, while adults face higher risks of life-threatening bleeding. However, symptom profiles can overlap, underscoring the need for comprehensive evaluation. Anyone experiencing unexplained neurological episodes—especially recurrent TIAs or spontaneous intracranial hemorrhage—should undergo thorough cerebrovascular assessment to rule out moyamoya disease.