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Parkinson's Disease (PD) is a progressive neurological disease involving loss of neurons in a part of the brain called the substantia nigra. This results in a reduction in the amount of the chemical dopamine, a chemical messenger or neurotransmitter. When 80% of dopamine in the brain is depleted, the symptoms of Parkinson's disease develop. The main symptoms are tremor, slowness of movement, stiffness and impairment of balance. It is a highly treatable disease and the life span is not shortened.  The
image to the right presents 2 images of the substantia nigra. The dopamine
containing neurons are in the substantia nigra and appear black in the
pictures. The upper image is from a normal brain, and the lower image
is from an individual with Parkinson's Disease. The loss of dopamine neurons
in the Parkinson's diseased brain is evident by less blackened areas.The loss of dopamine in an area of the brain called the striatum is the main chemical abnormality and there is a correlation between dopamine loss in this area of the brain and the severity of the symptoms. It is thought that exposure to some unidentified environmental toxin in a person who has a certain genetic predisposition causes the person to develop the disease. Inside the dopamine neurons, there are structures called mitochondria which use oxygen to turn food into energy. These mitochondria may be damaged in people with Parkinson's Disease. Who Gets Parkinson's? Parkinson's Disease affects about 0.3% of the general population, but 3% or more of those are older than 60. There are approximately 60,000 people diagnosed with the disease per year. The average age of onset of symptoms is 60, but 5% to 10% of patients have symptoms before the age of 40. The prevalence is expected to triple in the next 50 years. How is Parkinson's Diagnosed? Persons are diagnosed based on the symptoms they have and the physical examination. There are no standard laboratory tests available although testing is often done to exclude other similar diseases. A significant improvement in symptoms related to taking the medication carbidopa/levodopa is helpful in making the diagnosis since all patients with Parkinson's Disease respond to this medication. |
