[Parkinsonism. The differential diagnosis].
Considering the high prevalence of parkinsonism in people over the age of 50 and the impact of this syndrome on the patients' lives, it is important that physicians dealing with elderly people are familiar with the difficult differential diagnosis of Idiopathic Parkinson's disease (IPD). The diagnosis of IPD is entirely clinical. For a diagnosis of parkinsonism, bradykinesia must be present, and at least one of the following signs, muscular rigidity, rest tremor or postural instability. The most common cause of parkinsonism is Parkinson's disease. The two conditions that are most commonly misdiagnosed as Parkinson's disease, are essential tremor and arteriosclerotic pseudoparkinsonism. By using the proposed clinical criteria misdiagnosis can be reduced. Magnetic resonance imaging (MRI), 123I-iodobenzamide single photon emission computed tomography (IBZM-SPECT) scan and sphincter electromyogram may help in recognising alternative causes of parkinsonism.