Alcohol-related dementias
What are they?
Chronic excessive alcohol use can damage the brain in one of three ways. First, there is an acute disorder in which confusion is combined with neurological symptoms; this can be life-threatening and is called Wernicke's encephalopathy. Then, after recovery from Wernicke's, there often follows a chronic memory deficit, known as Korsakoff psychosis. Lastly, a more generalised dementia may arise with an emphasis on memory disorder and problems with behavioural regulation. In surveys of younger people with dementia causes due to alcohol account for at least 10% of cases.
Who gets it?
People who drink heavily and persistently may suffer any of these three disorders but often there will already be established physical features of alcohol damage such as liver disease and damage to nerves supplying sensation to the limbs (peripheral neuropathy). Wernicke's and Korsakoff's are more likely in people who neglect their diet and are generally run down. The concept of alcoholic dementia has been controversial. Although it is clear that chronic alcohol misuse does damage both the limbic structures (memory banks) and the frontal lobes (responsible for control of behaviour), it is likely that other factors contributed such as age, diet, self-neglect, repeated head injury and alcoholic seizures. Research has shown a high prevalence of vascular brain damage in those with alcoholic dementia. Sometimes people with an established dementia such as fronto-temporal dementia may begin to drink heavily as a result of behavioural dis-inhibition, and this may aggravate the picture.
What are the symptoms?
Wernicke's encephalopathy causes acute confusion, unsteadiness, double vision and squint. Of those who survive a majority develop Korsakoff psychosis. This is not really a psychosis in the modern sense but a memory disorder, especially the ability to retain new information. In alcoholic dementia, the main symptoms are amnesia and problems with behavioural regulation. At one extreme this may result in profound apathy so that the person will not be able to motivate themselves and care for their own or others needs; at the other, dis-inhibition causing social unconcern or socially unacceptable behaviour may lead to difficulties in holding down a job, aggression or inappropriate sexual advances.
How is it diagnosed?
Medical evaluation often shows other features of alcohol excess - old fractures, liver disease or neuropathy. Blood testing may show a characteristic pattern of blood enzymes if liver damage is present and there is often anaemia from dietary deficiency. Neuropsychological testing shows a pattern of memory deficiency, especially for new information, and frontal lobe deficits. Brain scanning shows no specific features although global atrophy (shrinkage) is usual and cerebrovascular changes common.
What is the prognosis?
Wernicke's encephalopathy is a serious acute medical problem with a mortality of around 20%. Of those who develop Korsakoff's, about 25% recover fully, 50% improve and 25% remain the same. It is important to recognise that improvement may continue for up to 2 years and so that rehabilitation should be available. Alcoholic dementia is the only dementia in which improvement may occur, provided abstinence of alcohol is achieved.
Are there any treatments?
At present the treatment of alcoholic dementia involves treating the causes of collateral damage. Stopping drinking is the most important strategy and help may be available from a Community Alcohol Team. Attention to smoking cessation, improved diet, B-group vitamins and treatment of high blood pressure are all important.
Where can I get information?
Most health authorities have a Community Alcohol Team, accessed via primary care services and Alcoholics Anonymous (AA) have branches in most parts of the country ( www.alcoholics-anonymous.org.uk/ ). Specialist psychiatric or neurological services will conduct an assessment and make a diagnosis following referral from the General Practitioner.
Robert C. Baldwin,
Consultant Psychiatrist and Honorary Professor of Old Age Psychiatry,
Manchester Mental Health Partnership,
York House,
Manchester Royal Infirmary,
M13 9WL
England
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