Clinical Lewy body syndromes.

Lewy bodies are spherical, intracytoplasmic, eosinophilic, neuronal inclusions comprising abnormally truncated and phosphorylated intermediate neurofilament proteins, alpha-synuclein, ubiquitin, and associated enzymes. The clinical presentation of LB disease varies according to the site of LB formation and associated neuronal loss. Three main clinicopathological syndromes have been described--movement disorder, autonomic failure, and dementia. Parkinsonism is the most common presentation of LB disease developing in middle life. In older patients, a mixture of cognitive, autonomic, and motor dysfunction is more common. Dementia with LB (DLB) is a relatively recently described clinicopathological syndrome that accounts for up to 20% of all cases of dementia in old age. Patients, typically in their seventh and eighth decades, have LB pathology in cortical neurons as well as in the brain stem. LB disease should be considered in the differential diagnosis of a wide range of clinical presentations including episodic disturbances of consciousness, syncope, sleep disorders, and unexplained delirium.