DEVELOPMENT OF DIAGNOSTIC TESTS OF ALZHEIMER’S DISEASE: MONITORING THE CSF
Many of the diseases that afflict mankind can be diagnosed with relative ease by examining the blood for abnormal changes or looking for specific diagnostic indicators in other body fluids, for example the urine and, particularly for diseases that affect the nervous system, the cerebrospinal fluid (CSF). There are currently many studies seeking such ‘peripheral’ markers of the presence and severity of Alzheimer’s disease. If identified, not only might they help with diagnosis, but they might also assist in monitoring the effectiveness of treatment when this becomes available.
Some of the earliest attempts at isolating diagnostic markers involved examining the CSF for changes in its biochemistry that would reflect the biochemical abnormalities that we know occur in the brain. Although there have been some reports of differences between people with Alzheimer’s disease and normal people of the same age without any intellectual deficit, there has been too much overlap between the two groups to enable the biochemical differences in question to indicate reliably the presence or absence of the disease. Similar attempts have been made to examine the changes in the blood and again the results have been disappointing.
More recently, and in many ways more hopefully, researchers have been trying to identify changes in the CSF and the blood that relate not to the biochemical changes within the brain, but to the structural abnormalities that develop in Alzheimer’s disease. Attempts are in hand to try to make the diagnosis by proving that the blood or CSF contains substances which indicate that the brain, in its turn, contains more senile plaques or neurofibrillary tangles than it should. At the time of writing this seems a much more logical approach and several tests have arrived at the point of clinical trial. It will probably be a year or two, however, before we know whether they are going to live up to expectations.
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General Health
UNTREATABLE CAUSES OF DEMENTIA: CEREBRAL TUMOURS
A cerebral tumour can cause dementia. Such tumours can be divided into two types – primary and secondary. Primary cerebral tumours are those that arise within the brain itself whereas secondary tumours spread there from a site somewhere else in the body, usually arriving via the bloodstream. Secondary tumours arise when a few cells from a tumour, say a cancer of the breast, are taken by the bloodstream and planted as seeds in the brain, where they grow and destroy brain tissue. Sometimes there are many small secondary deposits. They may cause all sorts of other symptoms and side-effects and don’t always cause dementia.
Since most brain tumours are unsuitable for X-ray therapy or surgical removal, it is usually only possible to treat the symptoms, such as headache. However, some primary tumours, especially one called a meningioma, can often be completely and safely removed. A meningioma can grow to a very large size and still be removed. It is therefore another of the treatable conditions that can be diagnosed from a brain scan. In most tumours, unfortunately, although treatment can be given to improve the quality of life of the person concerned, the tumour will eventually be responsible for the patient’s death.
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General Health
