Abstract WP288: Stroke in Lyme Borreliosis: A Systematic Review and Meta Analysis of Cerebrovascular Events

Background: Lyme borreliosis, caused by Borrelia burgdorferi and related species, may involve the central nervous system as Lyme neuroborreliosis (LNB). While neurologic manifestations are common, the true incidence of cerebrovascular events (CVE: ischemic stroke or transient ischemic attack) in Lyme disease remains unclear. Clarifying this risk is essential for diagnostic strategies and stroke evaluation in endemic regions. Objective: To systematically review and meta analyze the incidence of cerebrovascular events among patients with Lyme borreliosis/LNB, and to characterize clinical patterns and diagnostic implications. Methods: We searched PubMed/MEDLINE and PMC through August 20, 2025, for studies reporting stroke or TIA among patients with Lyme borreliosis/LNB, and that provided numerators and denominators suitable for incidence calculation. Eligible designs included cohorts and hospital registries. Data were extracted independently and pooled using a random effects model (logit transformation). Wilson 95% confidence intervals (CIs) were calculated for each study. Case reports and series without denominators were summarized qualitatively. Results: Two eligible cohorts were identified: Mironova et al. (Finland, n=1,454; 9 CVEs, 0.62%) and Oschmann et al. (Germany, n=330; 4 CVEs, 1.21%). The pooled incidence proportion of any CVE was 0.78% (95% CI 0.42–1.46%). Heterogeneity was low (≈ 21%). Most events were ischemic strokes, often affecting the posterior circulation, consistent with vasculitic pathology. A larger case based systematic review (n=88 patients, not included in pooling) confirmed that ~76% of cerebrovascular LNB cases were ischemic strokes and 11% TIAs. Major guidelines advise against routine Lyme testing in all stroke patients, but testing is reasonable in younger individuals from endemic areas with compatible clinical or cerebrospinal fluid findings. Conclusions: Stroke is a rare complication of Lyme borreliosis/LNB (~0.8%), but when present, it is typically ischemic, posterior circulation, and associated with vasculitis. Clinicians should maintain vigilance in endemic settings, balancing diagnostic yield with guideline recommendations to avoid unnecessary testing.