Parkinson’s Disease was first described in 1817 by James Parkinson. It is a common disorder of the brain. In Parkinson’s Disease, certain brain cells called neurons deteriorate. The exact reason for this process is not known. These neurons are important because they produce a substance called dopamine. Dopamine is a chemical “messenger” in the brain that helps the nervous system control muscle activity. When these neurons are destroyed dopamine is not produced at the normal rate.
Parkinson’s Disease belongs to a group of conditions called Motor System
Disorders. An abnormally low supply of dopamine causes Parkinson’s symptoms to appear.
- the commonest symptoms are involutary tremors (shaking) and slowness of movement.The tremor activity is usually decreased by action and increased by emotion. These tremors are usually occur on both sides or can be more prominent on one side of the body. The characteristic of slowness and decrease of voluntary movement can be attributed to the neuronal degeneration from unknown causes.
- Rigidity is result of stiffness to the limbs, referred to as “lead-pipe” rigidity which is usually prominent on one side. The phenomenon ‘cogwheeling’ results from stimultaneous movement of the opposite limb increasing the tone of the tremor casuing a jerky resistance to passive movement.
- Facial features are expressionless and stoney, conveying the patients cold lifeless emotions. Speech is altered to a hurried monotonous slurring. Dribbling is uncontrolled, due to the diffculity in swallowing that occurs as the disease progresses.
- Postual changes occur, causing a characteristic stooped position and a shuffling gait. This type of postual change is reffered to as ‘simian’, which describes the forward flex of the spine, immobility of the arms and facial features. Balance is impaired and sitting position is characterised by the torso bent forward and motionless.
- Additional symptoms include constipation, urinary difficulties, skin is oily, sweating is excessive and dementia is common in the later stages.
In Summary the primary and secondary symptoms:
The primary symptoms include:
– stiffness of limbs and trunk,
– tremor of hands, arms, legs, jaw and face
– slowness and poverty of movement
– difficulty with balance,
– and difficulty in walking.
Secondary symptoms of include:
– postural deformity,
– and difficulty in speaking.
There are some other neurological disorders which may have both primary and secondary parkinsonian symptoms. When this occurs, the condition may be referred to as Parkinson’s Syndrome, or Atypical Parkinson’s. For example, parkinsonian symptoms can be caused by tumors in the brain, repeated head trauma, prolonged use of tranquilizing drugs and with manganese and carbon monoxide poisoning. Even the commonly used drug, metaclopramide (Reglan), for stomach upset can cause parkinsonism.
The disease is both chronic, meaning it persists over a long period of time, and progressive, meaning its symptoms grow worse over time. It is not contagious nor is it usually inherited.
What Causes the Disease?
Parkinson’s Disease occurs when certain nerve cells, or neurons, in an area of the brain known as the Substantia Nigra become impaired or die. Dopamine is the normal chemical product produced by these neurons and acts as a chemical messenger responsible for transmitting signals between the Substantia Nigra and the next “relay station” of the brain, the Corpus Striatum. The Corpus Striatum acts to produce muscle activity. Loss of dopamine causes the nerve cells of the Striatum to fire out of control, leaving patients unable to direct or control their movements in a normal manner.
There are many theories to what causes cell death or impairment but the exact cause is still unknown.