PARKINSON’S DISEASE
In 1817, British Physician Dr. James Parkinson published a case series describing six patients afflicted with the “shaking palsy” (paralysis agitans), a chronic and progressive neurologic disorder called Parkinsonism i.e. loss of control of movement. Parkinson’s occurs when certain nerve cells in a part of the brain called the substantia nigra die or become impaired. Normally, these cells produce a vital chemical known as dopamine. Dopamine allows smooth, coordinated function of the body’s muscles and movement. When approximately 70% of the dopamine producing cells is damaged, the symptoms of Parkinson disease appear. Parkinson disease (PD) is recognized as one of the most common neurologic disorders, affecting approximately 1% of individuals older than 60 years. It is a progressive movement disorder marked by tremors, rigidity, slow movement (bradykinesia), and posture instability.
The motor symptoms of parkinson's disease result from the death of dopamine- generating cells in the substantia nigra, a region of the midbrain; the cause of this cell death is unknown. Sometimes it is genetic, but most cases do not seem to run in families. Exposure to chemicals in the environment might play a role.
It usually begin in a person's late fifties or early sixties. Parkinson disease causes progressive decline in movement controls, affecting the ability to control initiation, speed and smoothness of motion. Symptoms of parkinson's disease are seen in 15% of the people in the age 65-74 and almost 30% of people in age 75-84.
Most cases of parkinson's disease are sporadic. In that, there is a spontaneous and permanent change in nucleotide sequences. Sporadic mutations also involve unknown environmental factors in combination with genetic defects.
Causes
The immediate cause of PD is degeneration of brain cells in the area known as the substantia nigra, one of the movement control centers of the brain. Damage to this area leads to the cluster of symptoms known as "Parkinsonism".
Genetic: Researchers have identified specific genetic mutations such as α–synuclein and parkin, that can cause Parkinson's disease, but these are uncommon except in rare cases with many family members affected by Parkinson's disease
The presence of Lewy bodies: Clumps of specific substances within brain cells are microscopic markers of Parkinson's disease. These are called Lewy bodies, and researchers believe these Lewy bodies hold an important clue to the cause of Parkinson's disease.
A synuclein is found within Lewy bodies: Although many substances are found within Lewy bodies, scientists believe the most important of these is the natural and widespread protein called α-synuclein. It is found in all Lewy bodies in a clumped form that cells cannot break down. This is currently an important focus among Parkinson's disease researchers.
Risk Factors
Age: Young adults rarely experience Parkinson's disease. It ordinarily begins in middle or late life, and the risk increases with age. People usually develop the disease around age 60 or older.
Heredity: Having a close relative with Parkinson's disease increases the chances to develop the disease. However, risks are still small unless many relatives in family with Parkinson's disease.
Pathophysiology
• Loss of pigmented dopaminergic neurons of the substantia nigra pars compacta.
• The presence of Lewy bodies and Lewy neurites.
The loss of dopamine neurons occurs
most prominently in the ventral lateral substantia nigra. Approximately 60-80% of dopaminergic neurons are lost before the motor signs of parkinson's disease emerge.
Symptoms
Parkinson's signs and symptoms may include:
Tremors: Usually begins in a limb, often hand or fingers. The classic tremor of parkinson's disease is called as “Pill-rolling tremor”, because the movement resembles rolling a pill between the thumb and fore finger. This tremor occurs at a frequency of about three per second.
Slowed movement (Bradykinesia): It may involve slowing down or stopping in the middle of familiar tasks such as walking, eating or shaving, this may include freezing in place during movements (akinesia).
Rigid muscle: Muscle rigidity or stiffness, occuring with jerky movements replacing smooth motion. The stiff muscles can limit range of motion and cause pain.
Impaired posture and balance:
Postural instability or balance difficulty occurs. This may lead to a rapid, shuffling gait (festination) to prevent falling.
Loss of automatic movements: In Parkinson's disease, ability to perform unconscious movements, including blinking, smiling or swinging arms when walking may decrease.
Writing changes: Handwriting changes, with letters becoming smaller across the page (micrographia) and become difficult. Progressive problems with intellectual function (dementia).
Bladder problems: Parkinson's disease may cause bladder problems, including being unable to control urine or having difficulty urinating.
Constipation: Many people with Parkinson's disease develop constipation, mainly due to a slower digestive tract.
Smell dysfunction: Problems with sense of smell, may have difficulty identifying certain odours or the difference between odours.
Fatigue: Many people with Parkinson's disease lose energy and experience fatigue, and the cause is not always known.
Prevention
Because the cause of Parkinson's is unknown, there is no known way to prevent Parkinson’s disease. However, some research has shown that caffeine found in coffee, tea and cola may reduce the risk of developing
Parkinson's disease. Green tea also may reduce the risk of developing Parkinson's disease. Some research has shown that regular aerobic exercise may reduce the risk of Parkinson's disease.