Discussion

Moyamoya disease is a progressive cerebrovascular disorder which is characterized by stenosis of internal carotid arteries and its territories, which eventually lead to recurrent stroke episodes (8). In children, ischemic events are more common compared to adults, where adults are more prone to hemorrhagic manifestation (2). Ischemic and hemorrhagic strokes exhibit distinct lesion patterns, with ischemic strokes predominantly affecting the insula, putamen, operculum, and superior temporal cortex. In contrast, hemorrhagic strokes tend to involve more posterior and medial areas (10). Patients typically exhibit neurological deficits, with severity correlating to the extent of brain damage (11). Toh et al. (2023) revealed the prevalence of cognitive impairment in 54.4% of adult patients, including 31.55% with executive dysfunction. However, cognitive impairment had no association with stroke history, age or education level (9). In this case, a 20-year-old patient presented with headache, weakness of upper and lower left limbs, slurring of speech and facial deviation.  The exact etiopathogenesis of MMD is still uncertain. However, Diffusion-weighted MRI studies have revealed white matter alterations in watershed regions of children with MMD, even without overt stroke or silent infarction, suggesting ongoing injury due to chronic hypoperfusion (12). In adults, cognitive impairment, particularly in intelligence and arithmetic functions, is associated with white matter changes in specific brain regions, such as the uncinate fasciculus and inferior frontal-occipital fasciculus (13). There is a complex genetic association underlying MMD. Genetic variants in genes like ALPK1 and THBS2 have been linked to susceptibility for both coronary artery disease and ischemic stroke, which may share genetic architecture with MMD (14). Neuroimaging plays a crucial role in diagnosing and assessing. MRI studies reveal white matter alterations in children with MMD, particularly in watershed regions, even without overt stroke or silent infarction (12). Computational fluid dynamics simulations based on phase-contrast MRI data show significant hemodynamic changes in MMD patients, including higher pressure drop differences between internal carotid arteries and increased flow in posterior communicating arteries (15). CT angiography (CTA) findings in MMD reveal significant vascular changes. In MMD patients, the basilar artery tends to move towards the midline and upward, with enlarged posterior circulation vessels compared to healthy controls. The disease progression is characterized by a longitudinal shift of collateral channels from anterior to posterior components, potentially increasing the risk of hemorrhagic stroke in adults (16,17). In our case, MRI angiography and venography were sent and suggested of frontal, parietal, temporal lobe, basal ganglia and internal capsule acute/ subacute infarct, mainly proper middle cerebral artery territory with mass effect. To confirm further, a CT Angiogram was sent and suggested a narrowing of the bilateral internal carotid artery (left> suitable) through its course with collateral vessels around a clinoid segment of the bilateral internal carotid artery and bilateral middle cerebral artery territory- features suggestive of MMD. Treatment modalities for MMD vary depending on the type and patient’s age. For adult hemorrhagic MMD, bypass surgery significantly reduces stroke recurrence compared to medical treatment. However, bypass surgery for adult ischemic MMD shows no significant benefit over medical treatment (18). Antiplatelets have shown effective results in controlling the recurrence of infarcts in the cerebral artery, highlighting the complex role of antiplatelet treatments in cerebrovascular treatment. This case highlights the importance of considering MMD in young patients presenting with stroke-like symptoms, the critical role of imaging in diagnosis, and the potential for recovery with appropriate treatment.