The Importance of the Full Blood Count in Cerebral Ischemia: A Review of 609 Consecutive Young Patients with Stroke and Transient Ischemic Attacks

Background Almost half of ischemic strokes in young individuals are cryptogenic. Thrombophilia testing is routinely sent despite limited evidence linking to arterial cerebrovascular events. A full blood count may identify underlying hematological disorder. Methods We retrospectively reviewed all patients younger than 60 years with stroke and transient ischemic attack (TIA) presenting to a regional hyperacute stroke unit and daily TIA clinic from January 2015 to August 2016. We examined hematocrit level and platelet count, and whether abnormalities were further investigated. We examined if primary hematological disorders associated with stroke were considered, specifically myeloproliferative diseases (MPDs) and thrombotic thrombocytopenic purpura (TTP). Results Of 609 patients who presented with stroke or TIA, there were 161 abnormalities in hematocrit level or platelet count in 153 patients (25.1%). One hundred sixteen patients had high hematocrit levels (19%), 19 had thrombocytosis (3.1%), 26 had thrombocytopenia (4.3%), and 8 had abnormalities in both lineages (1.3%). A total of 119 patients had repeat testing (74%). Molecular investigations for MPD were warranted in 19 patients (3.1%), performed in 3 patients (.5%) with 2 patients subsequently diagnosed. ADAMTS13 analysis was indicated in 10 patients with thrombocytopenia, performed in 2 patients with 1 diagnosed with TTP thereafter. Conclusions One quarter of our cohort (n = 153) had abnormalities in hematocrit and/or platelets. MPD or TTP was present in 3 of the 5 patients specifically investigated. At least 22 patients (14%) merited further investigation. Although primary hematological disorders are rare in stroke aetiology, the full blood count is important to exclude known causes of arterial cerebrovascular events in young patients.