Parkinson disease and parkinsonism (N87)

Hypokinetic rigid syndrome is a clinical syndrome presenting with any combination of bradykinesia (slowness of movement or speed) with rest tremor, rigidity, and postural instability. The most common form of hypokinetic rigid syndrome is Parkinson disease (PD), a chronic, progressive disorder caused by degenerative loss of dopaminergic neurons in the brain. The diagnosis PD is made by a neurologist and based on distinctive clinical features from the history and neurological examination. At a minimum, bradykinesia plus either (asymmetrical) tremor or rigidity must be present in order to consider the diagnosis of PD. Postural instability usually appears later in the course