Diagnostic strategies in young patients with ischemic stroke in Canada

Background: A preliminary national survey of ischemic stroke in the young (15-45 years) undertaken by the Canadian Stroke Consortium indicated that in 44% of 356 patients, no cause was found. Objective: To determine the reason for this high incidence of diagnostic uncertainty in young patients with ischemic stroke. Methods: Neurologists in the ten Canadian stroke centers completed a detailed questionnaire for patients aged 15-45 years admitted to hospital between January 1993 and December 1997. Using a stepwise diagnostic algorithm incorporating clinical, neuroimaging, neurovascular and laboratory data, we divided patients into three groups: (1) those with established cause for the ischemic stroke, (2) those who remained unexplained despite adequate investigation, (3) those who remained unexplained but were, in our opinion, under-investigated. Results: In 197 patients (56%), an identified cause was established including cardioembolic sources (14%), extracranial arterial dissection (13%), lacunar infarcts (8%) atherosclerosis (6%). A miscellaneous group of 15%, included cerebral venous thrombosis, coagulopathies, vasculitis and others. In 159 patients (44%) with no apparent cause for their stroke, we considered only 81 (23%) adequately investigated, and 78 (21%) inadequately investigated. Conclusion: About one in five young patients was inadequately investigated by a stroke-oriented group of neurologists. The major problem appears to be restriction of investigations to neuroimaging alone (usually computerized cerebral tomography), without further tests such as cerebral angiography and cardiac imaging.