Key Points ÎParkinson disease is a progressive neurodegenerative disorder characterized by:
> Loss of dopaminergic neurons in the substantia nigra, as well as other dopaminergic and nondopaminergic areas of the brain;
> Cardinal motor symptoms of tremor, bradykinesia, and rigidity; > Significant disability and impaired quality of life due to motor complications.
ÎParkinson disease is primarily a clinical differential diagnosis from alternative parkinsonian syndromes; e.g., cerebrovascular disease, corticobasal degeneration, dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy.
ÎFeatures supportive of a diagnosis of Parkinson disease include:
> Unilateral onset with persistent asymmetry of motor signs, mostly affecting the side of onset;
> Progressive signs/symptoms, with falls occurring later as disease progresses; > Significant loss of smell (differentiates from progressive supranuclear palsy and corticobasal degeneration but not from multiple system atrophy); > Clinical course of ≥10 years with response to levodopa.
ÎPresumptive diagnosis of Parkinson disease can be confirmed by excellent patient response to levodopa or apomorphine challenge.
ÎAntiparkinsonian medications are only symptomatic, not neuroprotective. An MAO-B inhibitor can be used as initial treatment for mild symptomatic relief before instituting dopaminergic therapy. Initial dopaminergic therapy is dopamine agonists or levodopa. Dopamine agonists, COMT inhibitors, and MAO-B inhibitors are used as adjunctive therapies to levodopa.
ÎLong-term treatment with dopaminergic therapies are eventually complicated by:
> Off time (periods of return of symptoms when effect of medications wears off) > Dyskinesia (medication-induced involuntary movements, including chorea and dystonia).
ÎDeep brain stimulation is a surgical option in appropriate patients to:
> Improve motor function; > Reduce motor fluctuations, dyskinesia, and antiparkinsonian medication usage.
ÎDisease onset at older age and rigidity/hypokinesia as initial symptom can be predictive of:
> More rapid rate of motor progression; > Earlier development of cognitive decline and dementia.
