Parkinson's Disease Term Paper

Excerpt from Term Paper :

Parkinson's disease is a neurological disorder which is primarily diagnosed in people aged 50 and above. This degenerative disease affects the muscular movement, creates tremor and increases posture rigidity. First explained in 1817 by James Parkinson, this disease is prevalent throughout the world. In the United States as well as the UK around 2% of the elderly population is afflicted by this neurological disorder. In the U.S. alone there are around 1 million patients and every year 50,000 new cases are diagnosed with Parkinsonism and as a nation with a high percentage of elderly and aging population the figures may increase rapidly in the near future. A brief overview of the etiology, symptoms, treatment, patient care and education, would help us better understand the disease condition and its management.

Pathophysiology of Parkinson's Disease

Parkinson's disease is a disorder of the motor structures in the basal ganglia region of the brain. One of the observed features of this disease is the degeneration of the neurons in the 'substantia nigra' which are responsible for the production of dopamine. Dopamine is one of the important neurotransmitters of the body which plays a critical role in controlling the physical movements. A balance between acetylcholine (another neurotransmitter) and dopamine is essential for maintaining the normal motor functions of the body. So a decrease in dopamine producing neurons creates an imbalance in dopamine - acetylcholine ratio resulting in the manifestation of symptoms. The loss of pigmentation in the 'substantia nigra' region indicates the damage to the dopaminergic neurons. However the existence of lewy bodies and damage to other neuronal regions are also observed. [Jeff Blackmer]


The exact cause for the onset of Parkinson's disease has not yet been clearly established though a combination of factors have been identified as being responsible for the disease condition. Various theories are put forward to explain the etiology of the disease such as 'Accelerated Aging', 'Oxidative Stress', 'Environmental and Neurotoxins' and finally the theory of 'Genetic Predisposition'. It is generally observed that with increasing age there is a gradual decline in the dopaminergic neurons in the substantia nigra region of the brain. Experts suspect that in subjects with Parkinson's disease this normal aging process is accelerated in combination with some kind of stress related ischemic insult to the brain.

The currently widely accepted factor however is the oxidative theory which explains the role of the free radicals in the destruction of the neuronic cells. Dopamine is metabolized in the presynaptic neuron by the enzyme monoamine oxidase resulting in the production of Hydrogen peroxide which further reacts (with iron) to form the harmful hydroxyl free radicals which can inflict damage to the neuronic cells. Environmental toxins such as cyanide, methanol, organic solvents and industrial metals like zinc, manganese, etc. have also been identified to have neurotoxic effect. Synthetic meperidine also known as MPTP which is used as an alternative to heroin is now well-known for its neurotoxic effect. Genetic predisposition is greater in families with a history of the disease. Studies have confirmed a greater incidence of around 16% as against 4% in other control groups. [Jeff Blackmer]

Symptoms and Complications

The typical symptoms of Parkinson's disease include tremor, stooping posture, muscular rigidity. All voluntary movements get slowed down and the patient becomes bradykinetic. In advanced stages of the disease patients may experience frequent falls due to the postural imbalance. One common symptom is the 'resting tremor' which is observed in 70 to 80% of the patients. Micrographia or the pattern of small handwriting is also identified in patients with Parkinson's disease. Constipation is a common feature of this disease. The thinking process is also affected significantly and many patients experience slowness of thought or what is called in the medical parlance as 'bradyphrenia'. There is a general loss or gradual impairment of cognitive abilities and in advanced stages of the disease dementia manifests in one third of the patients. [David Nicholl]

Autonomic dysfunction, Depression and 'Cardio-pulmonary impairment' are the potential complications in patients with Parkinson's disease. 'Orthostatic hypotension' or the condition of 'low blood pressure when standing' is observed in advanced stages. The stooped posture of patients will severely restrict the lung capacity leading to breathing complications. Left unattended pulmonary function can be severely affected due to kyphosis. (bent back) Urinary incontinence and intestinal…

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