Small vessel stroke and white matter lesions

Damage to small penetrating vessels is an important unifying cause of ischemic and hemorrhagic strokes. Both types of stroke involve tiny arterioles and are often pathologic twins, arteriolosclerosis and lipohyalinosis being the predominant underlying causes.1 Another entity increasingly linked to small vessel damage is extensive leukoaraiosis: white matter lesions frequently seen on T2-weighted magnetic resonance scans of older people. In this issue of Neurology ®, Rost et al.2 report hospital-based findings from 3 stroke registries showing a greater burden of leukoaraiosis in participants with small vessel stroke (including both ischemic and hemorrhagic forms) compared to other ischemic stroke subtypes, supporting a link among these 3 entities. Thought of together, as peas in a pod, ischemic and hemorrhagic small vessel damage accounts for about one-third of all strokes and represents an important cause of morbidity and mortality. Ischemic small vessel stroke, often referred to as “lacunar,” is usually manifested as infarctions less than 1.5 cm in diameter on CT or MRI, and attributed to thrombosis of a penetrating vessel in the basal ganglia, thalamus, deep white matter, or brainstem. Studies suggest that lacunar strokes are associated with lower short-term disability and mortality than other ischemic stroke subtypes, and reported 1-year case-fatality rates are low, near 3%. …