Parkinsonism is a group of neurodegenerative diseases involving the substantia nigra (an area in the basal ganglia).
Etiology and classification
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1. 1ry idiopathic Parkinsonism |
| Parkinson’s disease Juvenile Parkinsonism |
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2. Secondary (aquired, symptomatic) |
| Parkinsonism: Infectious: post-encephalitic Drugs: neuroleptics, reserpine, tetrabenazine, lithium, flunarizine, cinnarizine. Toxins: ethanol, methanol, CO, Hg. Vascular: multi-infarct, hypotensive shock. Trauma: pugilistic encephalopathy. Other: parathyroid abnormalities, hypothyroidism, hepatocerebral degeneration, brain tumour, normal pressure hydrocephalus, syringomesenchephalia. |
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3. Heredodegenerative Parkinsonism |
| Autosomal dominant Lewy body disease. Huntington’s disease. Wilson’s disease. Hallervorden-Spatz disease. Olivopontocerebellar and spinocerebellar degenerations. Familial basal ganglia calcification. Familial Parkinsonism with peripheral neuropathy. Neuroacanthocytosis. |
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4. Multiple system degeneration (Parkinsonism plus) |
| Progressive supranuclear palsy Shy-Drager syndrome Striatonigral degeneration Parkinsonism dementia- ALS complex. Corticobasal ganglionic degeneration. Alzheimer’s disease. Hemi-atrophy Parkinsonism. |
Primary idiopathic Parkinsonism
Parkinson’s disease (paralysis agitans):
Affects patient 40-60 years old, of gradual onset, progressive course. Tremors are more pronounced than rigidity.
There are other idiopathic (of unknown cause) conditions as Parkinson’s disease that may cause Parkinsonism. In these conditions the problem is not the deficient production of dopamine but the inefficient binding of dopamine to its receptors located on globus pallidus.
Parkinson-Plus diseases
There are other disorders that are called Parkinson-Plus diseases. These include Shy-Drager Syndrome (SDS), Progressive Supranuclear Palsy (PSP) and Olivopontocerebellar Atrophy (OPCA which is also called Multiple System Atrophy). Patients often begin with typical Parkinson’s disease symptoms and these Parkinson-Plus diseases can only be diagnosed when other symptoms become apparent after some years. These Parkinson-Plus diseases usually progress more quickly than the typical main illness, and the usual anti-Parkinson’s medications do not work as well at controlling symptoms.
Secondary Parkinsonism
Secondary Parkinsonism (or briefly Parkinsonism) is a term used for a symptom constellation that is similar to that of Parkinson’s disease but is caused by other disorders or medications. Major reasons for secondary Parkinsonism are stroke, encephalitis, narcotics, toxins and carbon monoxide poisoning.
Post-encephalitic Parkinsonism
Affects any age, of acute onset regressive or stationary course. The patients presents with both rigidity and tremors equally.
Associated symptoms occulogyric (sudden spasm of conjugate movement mainly upwards), greasy, sialorrhoea, obesity, impotence / amenorrhea, diabetes insipidus and pyramidal signs if the cause involves extensive involvement of the brain tissues.
Atherosclerosis
Affects those over 60 years of gradual onset with remissions and exacerbations. In atherosclerotic Parkinsonism rigidity is more pronounced than tremors. This is usually associated with hypertension, diabetes, CHD, pyramidal signs.
