Timely diagnosis is vital in the treatment of Parkinson’s disease
Parkinson’s disease – A landmark paper from the UK Parkinson’s Brain Bank over 25 years ago looked at patients who had died with a condition that was thought at the time to be Parkinson’s disease (PD).
Pathologically, a total of 24 per cent of them did not have PD. Thus, they were misdiagnosed until the end of the illness. At the beginning of the disease, the misdiagnosis rate was probably even higher, said Prof Niall Quinn, Emeritus Professor of Clinical Neurology at the Institute of Neurology, University College London.
Around the same time, the UK Brain Bank diagnostic criteria for PD were published, and subsequently it was shown that if those criteria were applied strictly, the misdiagnosis figure came down to 10 per cent. The two degenerative conditions most likely to be misdiagnosed as PD are multiple system atrophy (MSA) and progressive supranuclear palsy (PSP).
People also present in clinics with cerebrovascular disease (stroke-like illness) and these too may superficially resemble Parkinson’s patients. Cases of essential tremor are also misdiagnosed – here, however, the other key features of Parkinsonism (slowness, rigidity, fatigue, etc) are absent.
Some of these conditions have much more significant implications for survival than PD, which reduces life expectancy by a small amount (quality of life is the main concern). Thus, on average, MSA or PSP patients die within seven years. Moreover, they tend not to respond significantly to the medications that are so effective in PD.
Over decades, a holy grail in research has been to identify a therapy that will modify PD or is neuro-protective. If this were available, it would be important to identify, and treat, patients with pre-motor or pre-symptomatic phases of the disease as early as possible.
Rapid eye movement behaviour disorder (RBD) is a condition where people are, unusually, able to act out their dreams whilst asleep. In one study, over 30 per cent of people with RBD went on to develop Parkinson’s and the RBD started a mean of 13 years before the Parkinson’s diagnosis.
The pathology of Parkinson’s thus starts to develop many years before the first motor symptoms. Cell loss spreads through the brain progressively, ultimately affecting the cortex.
“If we could get in at the earliest point and stop the underlying process of cell sickness and death, that would be fantastic,” said Prof Quinn, on a visit to Ireland recently. “Even in the early motor stages of PD, if we could block the spread of pathology in the brain – preventing the additional late stage Parkinson’s problems – that would be a huge advance.”
(Source: IMT)
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