Cerebral Amyloid Angiopathy, Hemorrhages and Superficial Siderosis

Abstract

See related article, pages 2894–2897. In this issue of Stroke , Feldman and coworkers1 describe 3 subjects with clinically somewhat atypical Alzheimer Disease (AD) and with a radiologically verified superficial siderosis (SS). In 2 of these patients, a neuropathological examination confirmed AD with concomitant cerebral amyloid angiopathy (CAA) and a premortem diagnosis of SS. Thus, a linkage was made between CAA, SS and atypical AD. This report highlights 3 issues of major interest. First, are chronic hemorrhages due to CAA and SS factors to be taken into account when dealing with subjects with AD or vascular cognitive impairment (VCI) due to CAA. Secondly, should we consider conducting imaging analysis in demented subjects displaying a somewhat atypical clinical phenotype of AD and/or VCI. Finally, can gradient-recalled echo (GRE) T2*-weighted MRI be exploited as a tool to identify those individuals with severe CAA? Superficial siderosis is defined as a condition where hemosiderin is deposited in the subpial layer of the central nervous system with the symptoms developing after chronic repeated subarachnoidal hemorrhages (SAH). Already in 1960, Iwanowski and Olszewski were able to experimentally reproduce SS in dogs by repeated subarachnoidal injections of blood.2 In the review article from 1995 by Fearnly and colleagues, one can find a comprehensive summary of the issues regarding clinical, radiological and pathological findings observed in this entity.3 In a more recent case report including a fine review of the literature, Levy and colleagues summarized the findings of the worldwide published reports (ie, 270 SS cases) and concluded that in only 3% of all reported SS cases was the etiology considered to be related to CAA. …