Parkinson’s Disease is a degenerative condition that affects the central nervous system. Dopamine containing cells in a region of the midbrain called the substantia nigra die off for reason or reasons that are currently not known. Dopamine cannot be administered to compensate for the lack of production as it does not cross the blood-brain barrier so cannot influence the central nervous system. The chemical l-dopa, the precursor to dopamine is often prescribed for Parkinson’s disease patients as this can cross the blood-brain barrier. A stage is reached though, where too few dopamine containing and manufacturing cells survive to be able to convert the i-dopa. This is why the treatment is ineffective for the later stages of the disease.
Diagnosis is usually by means of patient history and neurological exam. There is no test that confirms the presence of the disease with any degree of accuracy so it is a matter of ruling other possibilities out. L-dopa is often prescribed and if there is a marked improvement in symptoms Parkinson’s is likely.
Early symptoms of the disease are primarily related to movement and include rigidity, shaking, slowness of movement and difficulty with walking. Cognitive and behavioral problems usually appear later but it is not uncommon for them to surface during the early stages or even prior to a definite diagnosis. A Parkinson’s disease patient is six times more likely to suffer from dementia in later life than is normal. There is a roughly one third chance that the Parkinson’s patient will develop dementia.
The exact cause or causes of Parkinson’s Disease are not known but environmental toxins such as paraquet, Agent Orange and rotenone have all been implicated. Heavy metals exposure and subsequent accumulation in the substantia nigra part of the midbrain may be a factor but the evidence is inconclusive.