|
Dementia with Lew bodies (DLB) is now widely recognized as the second most common form of degenerative dementia after Alzheimer’s disease (AD), accounting for up to 20% of cases. It is clinically and neuropathologically distinct from AD, and consensus clinical and pathologic diagnostic criteria have been proposed. Core clinical features include the triad of fluctuating cognitive impairment, recurrent visual hallucination, and spontaneous parkinsonism. Pathologically, alpha-synuclein and ubiquitin positive, neuronal inclusion Lewy bodies, and Lewy neuritis are found in the neocortex, limbic cortex, subcortical nuclei and brainstem. Neurochemical features of DLB include a marked deficiency in the activitiy of the choline acetyltransferase. Simultaneously to the depletion of cortical acetylcholine, a reduction of dopamine level in the striatum, related to the substantia nigra neuronal loss, is also described. In the blood flow SPECT studies, a subtle difference in perfusion pattern with a greater degree of occipital hypoperfusion has been reported. Accurate diagnosis of DLB is clinically important as the management of psychosis and behavioral disturbance is complicated by sensitivity to neuroleptics. There is accumulating evidence to suggest to that DLB may be particularly amenable to cholinergic enhancers.
|