Juvenile parkinsonism: epidemiology, diagnosis and treatment.

Juvenile parkinsonism, with onset prior to age 21 years, is a relatively rare syndrome. It is caused by a group of heterogeneous entities that can present with a clinical picture similar to idiopathic Parkinson's disease or manifest parkinsonism as part of a spectrum of other signs. Diagnostic testing is guided by the presenting symptoms and aimed at uncovering potentially reversible and/or treatable causes. If an underlying condition is found, treatment is tailored accordingly. Otherwise, treatment is symptomatic and relies on medications commonly employed to treat idiopathic Parkinson's disease. Juvenile parkinsonism patients tend to be plagued by treatment-induced complications, so caution must be employed.