A neurological syndrome usually resulting from deficiency of the neurotransmitter dopamine as the consequence of degenerative, vascular, or inflammatory changes in the basal ganglia; characterized by rhythmical muscular tremors, rigidity of movement, festination, droopy posture, masklike facies, akinesia or bradykinesia, postural instability, shuffling gait, postural instability, and loss of automatic movement.
A syndrome similar to parkinsonism appearing as a side effect of certain antipsychotic drugs.
It is due to loss of dopamine containing substantia nigra cells.
It appears that about 50% of cells need to be lost before symptoms appear.
Although Parkinsons can be clearly traced to genetic factors, viruses, stroke or toxins such as pesticides in a few individuals, for the most part the cause of Parkinson's in any particular case is unknown (this is called sporadic PD).
There are different types of parkinsonism, the most common condition today is the one first recognized in 1817 by James Parkinson.
The differential diagnosis or list of potential causes for this disease includes: Parkinson's disease (and variations such as Parkinson's with Alzheimer's, vascular Parkinson's, etc.), multiple system atrophy, progressive supranuclear palsy, medications (e.g. antipsychotics, metoclopramide), diffuse Lewy body disease, corticobasal degeneration, and overexposure to substances such as manganese and MPTP.
At present there is no cure, but treatments do exist and are available.
While experts agree symptoms are due to a deficiency of the brain chemical, dopamine, they are uncertain as to why the nerve cells containing dopamine die.
Parkinson's disease is not contagious.
Parkinson's is uncommon in patients less than 40 years of age. It is found in about 1% of those greater than 50 and 3% of those aged 95 or greater and about 10% of 70 year olds show evidence of subclinical disease.
It is not a regular feature, intellectual impairment may occur in the later stages of the disease.
Parkinson's disease affects both men and women across all ethnic groups and is a serious health problem.
Prevalence varies greatly throughout the world, ranging from 14/100,000 in China to 328/100,000 in Bombay, India.
INCIDENCE & PREVALENCE
Slowness of movement (bradykinesia)
SYMPTOMS AND APPEARANCE
Associated symptoms often include
Orthostatic hypotension may occur associated with the disease or as a complication of medication. It is reported to be due to sympathetic denervation. The lesion involves postganglionic catecholaminergic but not cholinergic nerves
Ocular symptoms include
Decreased color discrimination and contrast sensitivity
Other problems with eyelid movement, and multistep saccades
The healthcare provider may be able to diagnose secondary parkinsonism based on the patient's history, symptoms, and physical examination.
However, the symptoms may be difficult to assess, particularly in the elderly.
For example, the tremor may not appear when the person is sitting quietly with the arms in the lap. The posture changes may be similar to those caused by osteoporosis or other changes associated with aging. The lack of facial expression may be a sign of depression.
SIGNS AND TESTS
Examination may show increased muscle tone, tremors of the Parkinson's type, and difficulty initiating or completing voluntary movements. Reflexes are usually normal.
Tests are not usually specific for secondary parkinsonism but may be used to confirm or rule out other disorders that may cause similar symptoms.
Diagnosis is mainly clinical and is based on the clinical findings.
There are many conditions which may be mistaken for parkinsonism.
Among the most common are side effects of drugs (mainly the major tranquilizers such as haloperidol), strokes involving the basal ganglia, degenerative disorders such as progressive supranuclear palsy (PSP), corticobasal ganglionic degeneration, olivopontocerebellar degeneration, multiple system atrophy, and Huntington's disease.
The pathological hallmark of Parkinson's disease are Lewy bodies, which are intracytoplasmic inclusion bodies in affected neurons of the substantia nigra.
Recently, alpha-synuclein has been identified as the main component of Lewy bodies in sporadic Parkinsonism. Lewy bodies are not found in progressive supranuclear palsy in abnormal numbers, although they are found in Alzheimer's disease.
Lewy bodies, in large numbers, can cause dementia.
They are also associated with medication intolerance and visual hallucinations.
There is presently no cure or prevention of Parkinson's disease.
However, the symptoms can be substantially or sometimes completely alleviated with medications, especially during the earlier stages.
Patients need to establish a strong relationship with their physician to maintain effective and comfortable levels of medication.
No treatment may be necessary for some patients with mild symptoms associated with the early stages of the disease.
HOW IS THE DISEASE TREATED?
Treatment with carbidopa-levodopa (Sinemet (TM)) is the single most helpful medication.
Levodopa has enabled patients with Parkinsonism to live normal life spans, and greatly ameliorates symptoms in most patients.
There is presently considerable controversy as to the value of adjunctive agents to levodopa.
As a summary, it seems prudent to recommend an approach which incorporates levodopa, direct dopamine agonists, and potential neuroprotective agents such as seligiline.
Patients with significant deficits which cannot be adequately treated with drugs may be suitable candidates for surgical approaches.
Unilateral thalamotomy -- can be used to reduce tremor.
Unilateral Pallidotomy is an effective technique for reducing contralateral levodopa induced dyskinesias.
Unilateral deep brain stimulation of the thalamus for tremor may also be of benefit for tremor.
Neural transplantation is no longer felt to be effective treatment.
Gamma knife -- thallamotomy or pallidotomy can be performed with focussed radiation.
Physical therapy is helpful in Parkinsonsm. It maintains muscle tone, flexibility, improves posture and gait.
Speech therapy and occupational therapy may help promote function and independence, and may help maintain skills and positive attitude and minimize depression.
Simple aids such as railings or banisters placed in commonly used areas of the house, special eating utensils or other devices may be of great benefit to the person experiencing some difficulties with daily living activities.
Social work or other counseling services may help in coping with the disorder, and obtaining assistance as appropriate (such as safety equipment, Meals-on-Wheels, volunteer services or other assistance).
Emotional support may help in coping with the changes caused by the disease.
The outcome varies and depends on the cause.
If the disorder is caused by medications, it is potentially treatable.
All other causes are not reversible and, to a greater or lesser degree, progressive.
The treatment of conditions that may cause secondary parkinsonism may decrease the risk of its development.
Medication use should only be under the supervision of the health care provider and people with conditions that require long-term use of antipsychotics, like schizophrenia, should be carefully monitored to avoid development of irreversible secondary parkinsonism.
Newer antipsychotic medications are less likely to cause secondary parkinsonism.
Surprisingly, coffee drinking reduces the risk of Parkinsonism.
Also, living in a rural area, drinking well water, farming, and exposure to pesticides may be risk factors for developing PD.
Smoking may also be protective in some situations.