Parkinson's Disease

Parkinson's disease (PD) is a common neurodegenerative disease. Early concepts looking at PD as purely a motor disorder have led the way to seeing it as a much more widespread neurological disease with affective, cognitive, and autonomic manifestations.The etiology of PD is still unknown, but important steps have been made to understand its pathogenesis. To a large extent, these derived from the identification of genetic variants of PD. Mutations in several genes have been discovered that cause monogenic PD, while GWAS has identified other loci associated with sporadic disease.Several drugs are now available for the treatment of PD patients. These include drugs specifically aimed at motor symptomatology (levodopa, dopamine agonists, monooxidase B inhibitors, and amantadine) and agents for treatment of cognitive, affective, and autonomic manifestations. Levodopa is undoubtedly the most efficacious known agent to treat the motor dysfunction, but it has short-term and long-term adverse effects, limiting its use. Therefore, treatment of the initial stages of PD usually starts with dopamine agonists or with monoamine oxidase inhibitors. Anticholinergic drugs, once the mainstay therapy of PD, are now rarely used, except for the control of tremor.As the motor symptoms are relatively efficiently controlled, the nonmotor symptoms of PD become the main problem in the management of PD patients. Therapy for cognitive impairment and for depression is available, but there is need to develop newer and more efficacious therapies.