Atypical Alzheimer’s Disease, Mixed Dementia, and Amyloid Angiopathy

Abstract

Alzheimer’s disease typically presents with episodic, short-term memory impairment. There are three principle variants or atypical forms of Alzheimer’s disease: (1) posterior cortical atrophy, (2) logopenic aphasia, and (3) frontal Alzheimer’s disease. Each of these syndromes has a characteristic phenotype that can be identified clinically. Each of the phenotypes can be caused by other neurological disorders besides Alzheimer’s disease and differential diagnosis is an important part of the approach to neurological care. Mixed dementias are common, particularly the association of Alzheimer’s disease with cerebrovascular disease. Mixed dementia may also occur with Alzheimer’s disease in combination with Lewy body pathology and TDP-43 protein inclusions. Amyloid angiopathy is a vascular disorder with amyloid accumulation in the blood vessels and usually presenting with lobar hemorrhage. When there is prominent inflammation, patients may improve with treatment with steroids or anti-metabolites.