Lewy body disorder

Figure 7.1 Differential diagnosis of dementia (AD = Alzheeners disease, DLBD dementia with Lewy body disorder, DLB = dementia with Lewy bodies)...

Dementia with Lewy bodies (DLB) is considered the second most common cause of dementia after AD. The disorder is characterized by progressive fluctuating cognitive impairment, visual hallucinations and motor features of Parkinsonism. Neocoitical cholinergic activity is more severely depleted in DLB than in AD, and DLB also affects the caudate nucleus, the thalamus and the brain stem. Tolerability of ChEI in DLB appears similar to AD, with some gastrointestinal effects and muscle cramps. 

Turner R., DAmato C., Chervin R., (2000). Blaivas M. The pathology of REM-sleep behavior disorder with comorbid Lewy body dementia. Neurology 55, 1730-2. 

TABLE 45-1 a-Synuclein diseases Idiopathic Parkinson s disease Dementia with Lewy bodies Pure autonomic failure REM sleep behavior disorder Lewy body dysphagia Incidental Lewy body disease Inherited Lewy body diseases Multiple system atrophy... 

The new work has established that a neurodegenerative pathway leading from soluble to insoluble, filamentous a-synuclein is central to Lewy body diseases and multiple system atrophy. The development of experimental models of a-synucleinopathies has opened the way to the identification of the detailed mechanisms by which the formation of inclusions causes disease. These model systems have also made it possible to identify disease modifiers that may well lead to the development of the first mechanism-based therapies for these diseases. At a conceptual level, it will be important to understand whether a-synuclein has a role to play in disorders, such as autosomal-recessive juvenile forms of parkinsonism caused by mutations in the Parkin, DJ-1 and PINK-1 genes, or whether there are entirely separate mechanisms by which the dopaminergic nerve cells of the substantia nigra degenerate in Parkinson s disease and in inherited disorders with parkinsonism. 

Dementia with Lewy bodies A disorder of consciousness 265... 

Wesnes KA, McKeith IG, Ferrara R, et al Effects of rivastigmine on cognitive function in dementia with Lewy bodies a randomized placebo-controlled international study using the cognitive research computerized assessment system. Dement Geriatr Cogn Disord 13 183-192, 2002... 

Schizophrenia is certainly not the only disorder with such impairments in cognition. Autism, poststroke dementia, Alzheimer s disease, and many other organic dementias (parkinsonian/Lewy body dementia, frontotemporal/Pick s dementia, etc.) are also associated with some cognitive dysfunctions similar to those seen in schizophrenia (Fig. 10—4). 

Regarding the NE system, loss of neurons in the LC and the existence of Lewy bodies have been shown by analysis of post mortem brains of PD patients (Zarow et ah, 2003) (Hoogendijk et ah, 1995) (Jellinger, 1991) (Chan-Palay and Asan, 1989). Reduced levels of NE in addition to disturbances in other related neurotransmitter system like the serotonergic may account for clinically relevant symptoms like depression, dementia, sleep disorders and autonomic dysfunction seen in PD. 

Research indicates that typical and atypical neuroleptic drugs increase the vulnerability of neurons to cell death and even kill brain cells and that the risk increases in patients already suffering from brain disorders such as Alzheimer s (chapter 5). Consistent with this, Sechi et al. (2000) reported on a case of NMS following exposure of a patient with familial dementia with Lewy bodies to low doses of risperidone. 

Lanctot KL, Herrmann N. Donepezil for behavioural disorders associated with Lewy bodies a case series. Int J Geriatr Psychiatry 2000 15(4) 338-45. 

---