Parkinson’s Diseases is a slowly progressive neurodegenerative disorder. It results from dopamine depletion caused by degeneration of dopaminergic nigrostriatal system, leading to a neurotransmitter imbalance between dopamine and acetylecholine in corpus striatum part of the brain. It is expressed in the form of symptoms and signs that include akinesia (loss or impairment of the power of voluntary movement), tremor, rigidity (inflexibility or stiffness) and unstable posture. Following is the view of 6 different dimensions of Parkinson’s Disease.
1. Etiology Or Cause of Parkinson’s Disease:
No specific cause is known for Parkinson’s disease however broadly speaking both genetic and environmental factors are considered to be responsible for its development.
A. Primary Idiopathic Parkinson’s Disease:
A multifactorial cause is considered to contribute towards the development of primary idiopathic Parkinson’s disease. This means that when the suspected environmental factors affect the person with genetic predisposition, it leads to destruction of neurons that produce dopamine.
B. Secondary Parkinson’s Disease:
I. Relatively Frequent Causes:
A variety of factors can cause secondary Parkinson’s disease. These include traumatic brain injury, anoxic (lack of oxygen) brain injury, tumor, hydrocephalus and cerebrovascular accident of the brain (stroke) both in the form of an infarct and intracranial bleed.
Certain drugs, which are antagonists of dopamine, can not only precipitate Parkinson’s disease in susceptible individuals but also can aggravate existing Parkinson’s disease. These drugs include neuroleptics such as haloperidol, thioridazine, fluphenazine and other dopamine receptor antagonists such as metoclopramide.
Then there are infections that have a role in the development of Parkinson’s disease. The prominent infections causing this include acquired immunodeficiency syndrome (AIDS), St. Louis encephalitis, von Economo’s and other influenza related encephalitis.
2. Parts of The Brain Affected by Parkinson’s Disease:
Various interconnected and interrelated parts of the brain are affected by Parkinson’s disease. These include cortical and sub-cortical structures that are responsible for the modulation of movements. Disruption of their function results in various motor and movement disorders, which are a hallmark of Parkinson’s disease. These structures include pyramidal and extrapyramidal or motor and premotor cortices along with basal ganglia. Basal ganglia have many nuclei that are affected by the disease. These include striatum (caudate and putamen), subthalamic nucleus, globus pallidus and substantia nigra.
Parkinson’s disease is a result of dopamine depletion due to degeneration of dopaminergic nigrostriatal system. This dopamine depletion causes imbalance between dopamine and acetylecholine, which are the neurotransmitters that are normally present in corpus striatum. This imbalance of the neurotransmitters leads to development of characteristic movement disorders of the Parkinson’s disease. This mechanism of development of the disease guides the treatment for it. The treatment is aimed at correcting this imbalance of neurotransmitters by blocking acetylecholine with anticholinergic drugs or by administering levodopa, which is a precursor of dopamine.