Watershed infarcts underpin cortical link to early post-stroke seizures
MedWire News: Stroke patients are at increased risk for early-onset seizures if their infarct is located in a watershed area rather than in an arterial territory, a study indicates.
The research by Christian Denier (Centre Hospitalo-Universitaire de Bicêtre, Paris, France) and colleagues confirms the association between cortical infarcts and early-onset seizures. But the team shows that this link is largely caused by the seizure risk associated with watershed infarcts - those that occur at the boundary of two arterial territories.
Overall, 4.3% of 328 patients with magnetic resonance imaging-confirmed stroke suffered early-onset seizures (within 14 days of stroke onset). Early-onset seizures did not afflict any of the 150 patients without cortical involvement, whereas it affected 7.9% of 178 patients with cortical infarcts.
Among patients with cortical infarcts, 23.1% of the 26 patients with watershed infarcts suffered early-onset seizures, a significantly higher rate than the 5.3% seen among the 152 patients who had infarcts within an arterial territory.
The association persisted after accounting for confounders, with watershed infarcts increasing the risk for early-onset seizures 4.7 fold. Other variables, such as age, gender, diabetes, hypertension, and stroke severity did not affect seizure risk.
"Stroke-related early-onset seizures are thought to result from cellular biochemical dysfunctions leading to electrically irritable tissue," Denier and team write in the Archives of Neurology.
They say that two distinct mechanisms may underlie watershed infarctions: hemodynamic compromise and microembolism. "Both could promote seizures via focal hypoperfusion or distal artery-to-artery embolism," they note.
The team concludes: "Future explorations, including brain diffusion-weighted and perfusion imaging and ultrasound detection of microembolic signals, should help us better understand the physiopathologic features of these infarcts and their association with early-onset seizures."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Eleanor McDermid