Diagnosis, prognosis, and management of cryptogenic stroke.

Despite many advances in our understanding of ischemic stroke, cryptogenic strokes (those that do not have a determined etiology) remain a diagnostic and therapeutic challenge. Previous classification approaches to cryptogenic stroke have led to inconsistent definitions, and evidence to determine optimal treatment is scarce. These limitations have prompted international efforts to redefine cryptogenic strokes, leading to more rigorous diagnostic criteria, outcome studies, and new clinical trials. Improvement in our ability to detect paroxysmal atrial fibrillation in patients with cryptogenic stroke has strengthened the idea that these strokes are embolic in nature. Further, better understanding of acute biomarkers has helped to identify otherwise occult mechanisms. Together, these strategies will inform long-term outcomes and shape management.