Implications of cortical superficial siderosis in CAA Superficial relationships

Advanced cerebrovascular amyloid deposition, defined as cerebral amyloid angiopathy (CAA), is a recognized cause of brain bleeds. CAA-related bleeds include symptomatic lobar macrobleeds, small and typically silent cerebral microbleeds, or superficial cortical hemorrhages that follow the curvilinear shape of the surrounding cerebral gyri. This latter group-designated as convexity subarachnoid hemorrhage when acute and cortical superficial siderosis (cSS) when chronic(1)- has proven particularly relevant to clinical practice. Their proximity to the cortical surface appears to be the trigger for transient focal neurologic symptoms (TFNEs or "amyloid spells") in a substantial proportion of individuals presenting with this syndrome.(2,3) The other major clinically important role of cSS is as a marker for increased intracerebral hemorrhage risk. CAA patients with cSS, particularly when disseminated (affecting more than 3 sulci) or multifocal, appear to have approximately 3 times the hazard ratio for recurrent hemorrhage than those without cSS.(4-6)