Abstract
A cerebral stroke is a heterogeneous entity and-in the context of this heterogeneity-a cryptogenic stroke, that is, of unknown origin at the time of diagnosis, finds a worthy position. Cryptogenic strokes are ∼25% of ischaemic strokes and in hindsight, they often appear to be of obvious or highly presumptive origin. Knowledge of the causes of a cerebral stroke that are not immediately evident is, therefore, fundamental for the purposes of correct secondary and, hopefully, primary prevention. Certainly, in fact, a cryptogenic stroke may require appropriate treatment, which is similar to a stroke whose origin is immediately evident. Equally certainly, however, cryptogenic stroke can benefit from specific treatments, which the lack of diagnosis of origin is destined to nullify. Therefore, it must unfortunately be accepted that a minority of cryptogenic strokes remain without a culprit and, therefore, without a specific corrective treatment. However, the insistent deepening of the diagnostic process in 'obscure' cases must also be pursued. Only the unyielding examination of these cases, in fact, is destined to identify a covert vasculitis, Fabry disease, occult atrial fibrillation, or one of the many pathologies, often far from rare, which require a therapy as specific as it is life-saving. In this brief review, therefore, we will try to fully expand on the identifiable causes of cryptogenic stroke.