How is CJD diagnosed?
At present there is no single test for CJD. If CJD is suspected, the first course of action is to discount any other possible diseases which could account for the symptoms and may be treatable, such as chronic meningitis or dementia. To determine this, a neurological exam would take place, and other physicians may be consulted to reach a conclusion. Diagnostic tests may be carried out in order to discount other, more common causes of dementia, which may involve testing spinal fluid (a spinal tap) or an EEG (electroencephalogram) which records the electrical patterns of the brain and can show abnormalities. The latter test can be particularly helpful as CJD can create a specific kind of abnormality which can sometimes be seen on an EEG. By carrying out tests on brain activity and functions it is possible to discount other causes of the patient’s symptoms, such as a brain tumour or a stroke. An MRI scan, (Magnetic
Resonance Imaging) can show patterns of degeneration in the brain which can also help to diagnose CJD.
CJD can only be confirmed by autopsy or brain biopsy. Through an autopsy the entire brain is examined, and therefore the characteristic ‘spongiform’ aspect of CJD infected brain tissue can be confirmed. A brain biopsy involves a surgeon removing a tiny amount of brain tissue from the patient which can then be examined to confirm the presence of CJD. This procedure does put the patient at some risk, and there is the possibility that the tissue removed will not be from an infected area of the brain. There is also a small risk that the surgeon may accidentally become infected with the disease if present. As a positive diagnosis of CJD does not actually help the patient in the long term, the biopsy is ordinarily discouraged as a course of action.