In Alzheimer's disease (AD), cerebral microbleeds (CMBs) play a crucial role in the pathophysiology of the disorder. This chapter reviews the available data that help in considering the meaning of CMBs in clinical terms and the underlying pathology in the context of AD. Evidence on the underlying pathology of CMBs can be sought from neuropathology studies, anatomical distribution in AD and clinical studies on related factors. Most studies on CMBs in AD demonstrated a cortico-subcortical predominance, but with some patients exhibiting CMBs both in deep and cortico-subcortical locations. Cerebral microbleeds are strongly linked to hypertensive vasculopathy. With studies on the relevance of CMBs in AD emerging, CMBs have become a factor of interest in the design of clinical trials, particularly with regard to the new generation of immunization therapies, which have been linked to the development of new CMBs.

Paraneoplastic strokes show a clinical picture different from those observed in stroke patients without cancer. Diffuse and progressive encephalopathy, either isolated or accompanied by focal neurological manifestations, is usual in disseminated intravascular coagulation, nonbacterial thrombotic endocarditis, and paraneoplastic vasculitis. The clinical presentation of paraneoplastic cerebral venous thrombosis includes severe, diffuse, and progressive headache due to intracranial hypertension, partial or generalized seizures, transient ischemia or cerebral infarct of venous origin, and progressive ischemic encephalopathy. The diagnostic process for paraneoplastic strokes is different from standard procedures for other types of stroke. Cerebral computed tomography (CT) and magnetic resonance imaging (MRI) can be normal in ischemic events caused by disseminated intravascular coagulation, or may show multiple images in several vascular territories in nonbacterial thrombotic endocarditis and vasculitis. Heparin may be effective in preventing cerebral infarction among patients with nonbacterial thrombotic endocarditis and does not increase the risk of hemorrhagic complications.