Parkinson disease

[Rihanna]

Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or postural instability. Diagnosis is clinical. Treatment aims to restore dopaminergic function in the brain with levodopa plus carbidopa and/or other drugs (eg, dopamine agonists, monoamine oxidase type B [MAO-B] inhibitors, amantadine ). For refractory, disabling symptoms in patients without dementia, stereotactic deep brain stimulation or lesional surgery and levodopa and an apomorphine pump may help.
(See also Overview of Movement and Cerebellar Disorders.)
Parkinson disease affects about

0.4% of people gt; 40 years
1% of people ≥ 65 years
10% of people ≥ 80 years

The mean age at onset is about 57 years.
Parkinson disease is usually idiopathic.
Juvenile parkinsonism, which is rare, begins during childhood or adolescence. Onset between ages 21 and 40 years is sometimes called young or early-onset Parkinson disease. Genetic causes are more likely in juvenile and early-onset Parkinson disease; these forms may differ from later-onset Parkinson disease because

They progress more slowly.
They are very sensitive to dopaminergic treatments.
Most disability results from nonmotor symptoms such as depression, anxiety, and pain.

Secondary parkinsonism is brain dysfunction that is characterized by basal ganglia dopaminergic blockade and that is similar to Parkinson disease, but it is caused by something other than Parkinson disease (eg, drugs, cerebrovascular disease, trauma, postencephalitic changes).
Atypical parkinsonism refers to a group of neurodegenerative disorders that have some features similar to those of Parkinson disease but have some different clinical features, a worse prognosis, a modest or no response to levodopa , and a different pathology (eg, neurodegenerative disorders such as multiple system atrophy, progressive supranuclear palsy, dementia with Lewy bodies, and corticobasal ganglionic degeneration).