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New Concepts in Lacunar Stroke Etiology: The Constellation of Small-Vessel Arterial Disease

Objective: To update the less frequent etiologies causing lacunar infarcts (LIs). To highlight recent advances in risk factors, clinical syndromes, topography, complementary tests and long-term prognosis in this subtype of ischemic stroke. Patients and Methods: The most important studies are analyzed, from CM Fisher works, selecting those referring to LIs of unusual etiology, and recent advances and controversies in the clinical management of LI are discussed. Results: LIs are found in approximately 11% of patients admitted with stroke. The pure motor hemiparesis (55%) constitutes the most usual lacunar syndrome. However, lacunar syndromes may not be caused by LIs in 10–20% of cases. LIs caused by microembolism and cholesterol embolism from the aortic arch are reviewed. Hematological diseases can also cause LI, such as polycythemia rubra vera, essential thrombocythemia and primary antiphospholipidic antibody syndrome. Other etiologies are carotid plaque embolism, severe stenosis of a perforated arteriole and amyloid angiopathy. Infectious arteritis by neurolues, neurocysticercosis, neuroborreliosis, by AIDS or Helicobacter pylori infection have also been associated with the presence of LIs. Likewise, inflammatory arteritis in systemic lupus erythematosus or granulomatous angiitis, cocaine abuse and panarteritis nodosa have been related to LI, although in the latter LI would be caused by a thrombotic microangiopathy and not by vasculitis. Conclusions: LI is an ischemic stroke subtype with a characteristic clinical presentation and a short-term favorable prognosis. Although high blood pressure constitutes the main risk factor and the main etiology, LIs may be caused, in less than 5% of cases, by various etiologies, mainly hematological diseases and infectious or inflammatory arteritis. It is essential to make a correct etiological diagnosis for LI as treatment will be different according to its etiology.