Lee Reese, Pharm.
Most cases are of unknown etiology and are referred to as idiopathic parkinsonims.
Men and women are affected equally. The prevalence of PD is about 100 per 100,000 population and the incidence is estimated at 20 per 100,000 people annually. The symptoms of PD develop insidiously and progress over time such that total immobility develops within 10-20 years despite drug therapy. Death is usually due to complications of immobility like aspiration pneumonia rather than PD itself. There are many theories but the exact etiology of PD is not known.