[Etiological workup for cerebral infarction in young adults]

identifying the cause of ischemic stroke in young adults is of major importance to prevent stroke recurrence. However, given the wide variety of potential underlying causes, the etiological workup of stroke in young adults requires a different approach from that in the elderly The purpose of this article is to provide a sequential diagnostic workup in order to optimize the yield of diagnostic tests, and to reduce their cost and risks for the patient. The first line screening mainly includes contemporary MRI of the brain and its vessels, and cardiac investigations which will assess the most frequent causes of stroke in this age group: arterial dissection and cardioembolism. The second line screening should be guided by context and clinical suspicion: lumbar puncture and immunological tests in case of angeitis suspicion; lumbar puncture, blood culture and serologies in case of infectious context; antiphospholipid syndrome, Holter-ECG, transoesophageal echocardiography, HIV and syphilis serologies in absence of context. Finally, the third line screening may include more invasive tests such as angiography and leptomeningeal biopsy in case of angeitis suspicion or genetic analyses. Despite such a comprehensive workup, about one third of cases will remain unexplained, leading to the diagnosis of idiopathic ischemic stroke.