This is an old revision of this page, as edited by King of Hearts (talk | contribs) at 19:39, 3 August 2006 ({{sprotect-banneduser}}). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.
Revision as of 19:39, 3 August 2006 by King of Hearts (talk | contribs) ({{sprotect-banneduser}})(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff) Medical condition| Parkinson's disease | |
|---|---|
| Specialty | Neurology  |
| Frequency | 0.2% (Canada) |
Parkinson's disease (also known as PD or Parkinson disease) is a degenerative disorder of the central nervous system, that affects the control of muscles, and so may affect movement, speech and posture. Parkinson's disease belongs to a group of conditions called movement disorders. It is often characterized by muscle rigidity, tremor, a slowing of physical movement (bradykinesia), and in extreme cases, a loss of physical movement (akinesia). The primary symptoms are due to excessive muscle contraction, normally caused by the insufficient formation and action of dopamine, which is produced in the dopaminergic neurons of the brain. PD is both chronic, meaning it persists over a long period of time, and progressive.
PD is the most common cause of parkinsonism, a group of similar symptoms. PD is also called "primary parkinsonism" or "idiopathic PD" ("idiopathic" meaning of no known cause). While most forms of parkinsonism are idiopathic, there are some cases where the symptoms may result from toxicity, drugs, genetic mutation, head trauma, or other medical disorders.
History
Symptoms of Parkinson's disease have been known and treated since ancient times. However, it was not formally recognised and its symptoms documented until 1817 in An Essay on the Shaking Palsy by the British physician Dr. James Parkinson. Parkinson's disease was then known as paralysis agitans. The underlying biochemical changes in the brain were identified in the 1950s, due largely to the work of Swedish scientist Arvid Carlsson who later went on to win a Nobel prize. L-dopa entered clinical practice in 1967, and the first study reporting improvements in patients with Parkinson's disease resulting from treatment with L-dopa was published in 1968.
Symptoms
Parkinson disease affects movement (motor symptoms). Typical other symptoms include disorders of mood, behavior, thinking, and sensation (non-motor symptoms). Individual patients' symptoms may be quite dissimilar; progression is also distinctly individual.
There are four major dopamine pathways in the brain; the nigrostriatal pathway, referred to above, mediates movement and is the most conspicuously affected in early Parkinson's disease. The other pathways are the mesocortical, the mesolimbic, and the tuberoinfundibular. These pathways are associated with, respectively: volition and emotional responsiveness; desire, initiative, and reward; and sensory processes and maternal behavior. Reduction in dopamine along the non-striatal pathways is the likely explanation for much of the neuropsychiatric pathology associated with Parkinson's disease.
Motor symptoms
The cardinal symptoms are:
- tremor: normally 4-7Hz tremor, maximal when the limb is at rest, and decreased with voluntary movement. It is typically unilateral at onset. This is the most apparent and well-known symptom. Howeve
- Parkinson J (2002). "An essay on the shaking palsy. 1817" (Reproduced). J Neuropsychiatry Clin Neurosci. 14 (2): 223–36, discussion 222. PMID 11983801.
- Cotzias G (1968). "L-Dopa for Parkinsonism". N Engl J Med. 278 (11): 630. PMID 5637779.