Ischemic stroke of unusual cause:: clinical features, etiology and outcome

The clinical features, etiology and neurological outcome of ischemic stroke of unusual cause (ISUC) have rarely been reported. We retrospective reviewed all patients with this stroke subtype entered in the Sagrat Cor Hospital of Barcelona Stroke Registry, which includes data from 2000 consecutive first-ever stroke patients admitted to the hospital between 1986 and 1995. Patients with previous ischemia and/or hemorrhagic stroke were excluded. Topographic, anamnestic, clinical and neuroimaging characteristics of ISUC were assessed. Predictors of this stroke subtype were determined by logistic regression analysis. Ischemic stroke of unusual etiology was diagnosed in 70 patients (32 men and 38 women), with a mean +/- SD age of 52 +/- 22.4 years. This stroke subtype accounted for 4.3% of all first-ever strokes and 6% of all first-ever brain infarcts. Etiologies included hematological disorders in 17 cases, infection in 11, migraine stroke in 10, cerebral infarction secondary to venous thrombosis in nine, primary inflammatory vascular conditions in six and miscellaneous causes in 17. In the multivariate analysis after excluding cerebral venous thrombosis (n = 9) and arterial dissection (n = 4), because of typical clinical and radiological features, independent predictors of ISUC included 45 years of age or less (odds ratio [OR] 14.8), seizures (OR 6.8), headache (OR 5.2), hemianopia (OR 2.6) and occipital lobe involvement (OR 3.0). Patients with ISUC presented a lower in-hospital mortality rate (7.1% vs. 14.4%; P < 0.05), were more frequently symptom free at discharge (35.7% vs. 25.8%; P < 0.05) and experienced a longer mean length of hospital stay (23.7 days vs. 18.2 days; P = 0.06) than non-ISUC patients. We conclude that ISUC is infrequent, etiologies are numerous and hematologic disorders are the most frequent cause. We emphasize the better prognosis and the need to distinguish it from other ischemic stroke subtypes which have a different treatment approach and outcome.