Parkinson's disease
What is Parkinson's disease?
Parkinson's Disease (PD) is a gradual, progressive neurological condition classically characterized by a tremor (usually at first in the hand), rigidity and slowness of movement; these symptoms initially occur on one side of the body. The disease becomes more common with age, particularly beyond the age of 60. It can though rarely present much earlier (before the age of 30), which is suggestive of an inherited form of disease.
What are the causes?
It is thought that PD is the result of both genetic (it does tend to run in families) and environmental factors. With respect to the latter, studies suggest that exposure to certain metals or toxins increases the susceptibility to PD. There is a decreased risk of PD in those who drink coffee and smoke cigarettes. Although the disease process is not completely understood, it is known that there is a decrease in one of the chemicals found in the brain, dopamine. Current treatments are aimed at addressing this deficiency.
What are the symptoms?
Parkinson's disease is thought to affect over six million people worldwide, and is slightly more common in men than in women. Up to 10% of sufferers are diagnosed before the age of 50.
How is the diagnosis made?
The diagnosis continues to be a clinical one. Imaging such as CT scans or MRI do not contribute to the diagnosis, nor are there any blood tests that are helpful.
What is the treatment?
There is no cure for Parkinson's disease. Treatment at this time is based on addressing the symptoms. There are six types of medication available: anticholinergics, amantidine, L-dopa, dopamine agonists, MAOI (monoamine oxidase inhibitors) and COMT-I (catechol-O-methyltransferase inhibitors). L-dopa is the precursor of dopamine, the brain chemical deficient in Parkinson's disease. Though still the mainstay of Parkinson's therapy, it is not without its own problems; long-term complications include fluctuations in effectiveness, abnormal movements ('dyskinesias') and psychiatric manifestations such as hallucinations. It is common practice at this time for younger patients to be tried on dopamine agonists first, on account of the fact that they have shown to delay the onset of early dyskinsias and fluctuations. As they have also been shown to be less effective and less well tolerated than L-dopa, older and less healthy patients are started on L-dopa at the onset.