sailor girlDementia With Lewy bodies

This text has been compiled with the help of Dr. Graham Lennox

Dementia with Lewy bodies is a preferred term which describes several common disorders causing dementia. In many hospitals this is the second commonest cause of dementia after Alzheimer's disease. The name for the disease comes from the presence of abnormal lumps which develop inside nerve cells called Lewy bodies. Following increasing pathological recognition, core clinical diagnostic features have been identified to allow diagnosis in life.

These diseases have been given a variety of names by different workers.

The main features of these conditions are


Several key areas of the brain undergo degeneration in this form of disease

When the brain from a patient with Lewy body dementia is examined at autopsy loss of nerve cells is seen from the midbrain region where the substantia nigra is located. Shrinkage of the brain is particularly seen in the temporal lobe, and parietal lobe.



The core feature of DLB is a progressive dementia.

A combination of key clinical features has allowed workers in many centres to diagnose this condition and distinguish it from other causes of dementia.


Clinical diagnostic criteria have recently been assembled at a recent Consortium meeting to produce a new set of criteria (McKeith et al, 1996).

  1. The central requirement is progressive cognitive decline of sufficient magnitude to interfere with normal social or occupational function. Prominent or persistent memory impairment may not necessarily occur in the early stages but is usually evident with progression.
  2. Two of the following are required for a probable, and one for a possible diagnosis of dementia with Lewy bodies:
  3. Features supportive of the diagnosis are:
  4. A diagnosis of dementia with Lewy bodies is less likely in the presence of:


There are no specific diagnostic tests for DLB.


In most patients the main diagnostic issue is to distinguish DLB from the commoner Alzheimer's disease (AD).

A more common diagnostic error is to attribute the clinical features of DLB to cerebral vascular disease such as multi-infarct dementia or Binswanger's disease.


There is no specific therapy that can stop the process of neurodegeneration in this form of dementia.

Therapy is limited to managing neuropsychiatric disturbances and the associated movement diosorders.

DLB causes several clinical problems with management. There are conflicting requirements in trying to treat the neuropsychiatric disturbance as well as the parkinsonism such that treatments for hallucinations, delusions and behavioural disturbance tend to make the movement disorder worse and vice versa.

Small scale studies suggest that the newer atypical neuroleptics such as clozapine and olanzapine may be able to treat psychotic symptoms without precipitating excessive parkinsonism.

These drugs may even be successful in treating hallucinations and delusions in patients with Parkinson's disease who are starting to dement. This would be a great advantage, because the traditional management involves the withdrawal of anti-parkinsonian medication, a process which often leaves the patient lucid but immobile. It is still reasonable to try to simplify anti-parkinsonian medication as a first step, particularly withdrawing drugs of lower potency (and particular tendency to cause confusion) such as anticholinergics and selegeline; where possible dopamine agonists should also be withdrawn, leaving most patients on levodopa alone.

Some studies in this area of therapy advise caution.

Neuroleptic sensitivity in dementia with Lewy bodies and Alzheimer's disease. (Lancet Vol 351 4 April 1998 pages 1032-33) Authors: Clive Ballard, Janet Grace, Clive Holmes.

The research letter to the Lancet is from the Newcastle group.

McKeith and colleagues originally reported that about half of all patients with Dementia with Lewy bodies (DLB) exposed to neuroleptic drugs experienced a severe adverse drug reaction which included deterioration in cognitive function, parkinsonism, drowsiness and some features of so-called neuroleptic malignant syndrome. Such patients has a three fold increase in mortality compared to those not exposed to such drugs (McKeith et al BMJ 1992; 305: 673-678). This may also occur in association with atypical neuroleptic drugs (McKeith et al Lancet 1995; 346: 699)

In the study that they now report in the Lancet the group have looked at the incidence if neuroleptic sensitivity in a group of 80 patients, 40 with pathologically confirmed Alzheimer's disease and 40 with pathologically confirmed DLB.

The authors make the following two recommendations:

The pharmaceutical industry is starting to recognise that the cognitive impairment of DLB may, because of its neurochemical differences, be more amenable to drug therapy than Alzheimer's disease.Initial anecdotal experience with cholinergic therpy in DLB has shown some promise.


The cause of this form of neurodegenerative disease is uncertain. There are overlaps between Alzheimer's disease and Parkinson's disease. Genetic studies are making some progress in revelaing a matrix of different genes which may contribute to development of DLB. This appears to be complex but may explain firstly the relationship of DLB to the other primary Lewy body disorders including Parkinson's disease and secondly the association with Alzheimer's disease. It remains to be seen whether genetic testing will be sufficiently simple to help in clinical diagnosis.

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