Parkinson’s disease falls in the class of conditions referred to as motor system disorders. These disorders are due to loss of nerve cells that produce dopamine in the brain. It is manifested by having tremors, lack of coordination, stiffness, instability of posture and slow movements. It occurs mostly in persons over 50 years of age (National Institute of Neurological Disorders and Stroke, Para. 1). Primary Parkinson’s disease is as a result of trauma to nerve cells which produce dopamine. Secondary Parkinson’s disease is due to trauma in the substantia nigra.
If it is damaged, it leads to the symptoms such as tremors. The other subtypes of Parkinson’s disease include juvenile Parkinson’s disease, iatrogenic (drug induced) Parkinsonism and post-encephalitic Parkinson’s disease (Duvoisin and Sage, pp 5). Etiology Parkinsonism is a condition caused as a result of a dysfunction in the brain specifically known as substancia nigra (Duvoisin and Sage, pp 1). This area consists of long and thin fibers of nerve cells which extend into the gray matter (known as corpus striatum) that is found in the cerebral hemispheres.
Dopamine is made in the substantia nigra and transmitted to the corpus striatum through these fibers. Dopamine therefore transmits signals to this region of the brain. However, in cases where the nerve cells in the substantia nigra are traumatized or they have become inefficient in the production and storage of dopamine, dopamine deficiency will occur. This is the basis of the symptoms that are seen in Parkinsonism (Duvoisin and Sage, pp 2). The trauma to the nerve cells (primary Parkinsonism) may be due to a number of causes such as chemical agents, tumors, stroke and viral encephalitis.
Dopamine deficiency may be due to certain drugs which either block dopamine action in the striatum hence transmission of signals is impaired. The most common form of Parkinsonism is known as Parkinson’s disease. It has been classified as neural degeneration since it involves specific nerve cells in the brain. It is believed to be due to Lewy bodies which are found in these cells. The specific etiology of Parkinson’s disease is not known (Duvoisin and Sage, pp 3). Symptoms Patients suffering from this disease will show three major symptoms namely; tremors, rigidity and bradykinesia.
The first and most common symptom is tremors which affects the hands and the foot. The shaking of the affected parts occurs at rest and these types of tremors are referred to as “pill rolling. ” These tremors occur intermittently and there frequency is enhanced when the person is nervous or stressed. The tremors are also experienced in other parts of the body such as the abdomen, tongue, jaws, lips, heart and diaphragm. Therefore, the person experiences a difficulty in talking and the voice is shaky (Duvoisin and Sage, pp 23).
Rigidity affects the muscles such as biceps and triceps. The reciprocal action of these muscles is affected in that when the arm is bent, the triceps fail to relax whereas on straightening the arms, the biceps do not relax. The rigidity impairs both the active and passive movement of the person. This rigidity is the basis for bradykinesia (slow movement) that is seen in such patients. However, there are cases whereby bradykinesia occur even without rigidity (Duvoisin and Sage, pp 27).