Improving the Diagnostic Accuracy in Parkinsonism
Improving the Diagnostic Accuracy in Parkinsonism
This can occur in both PD and AP. Focal dystonia can develop in patients with PD, especially in those with young-onset PD or one of the recessive forms of parkinsonism. This mainly involves dystonia of the foot, and can be dopamine-responsive (hence the frequent occurrence early in the morning during a deep 'off' phase). Different forms of dystonia occur in patients with AP. Focal dystonia of the neck muscles (retrocollis) or the eyelid muscles (blepharospasm) occurs in PSP. Focal dystonia of the neck muscles also occurs in MSA, but now in the form of a mixed antecollis-laterocollis (often fixed and painful). MSA can also present with focal dystonia of the vocal cords (spasmodic dysphonia), or a segmental dystonia of trunk muscles, causing lateroflexion (Pisa sign) or anteroflexion (camptocormia) of the trunk. Note that a Pisa sign or camptocormia can also occur in PD or as a side-effect of drugs (mainly neuroleptics). A full differential diagnosis is presented in Table 5. The presence of early, fixed limb dystonia suggests a diagnosis CBD.
Dystonia
This can occur in both PD and AP. Focal dystonia can develop in patients with PD, especially in those with young-onset PD or one of the recessive forms of parkinsonism. This mainly involves dystonia of the foot, and can be dopamine-responsive (hence the frequent occurrence early in the morning during a deep 'off' phase). Different forms of dystonia occur in patients with AP. Focal dystonia of the neck muscles (retrocollis) or the eyelid muscles (blepharospasm) occurs in PSP. Focal dystonia of the neck muscles also occurs in MSA, but now in the form of a mixed antecollis-laterocollis (often fixed and painful). MSA can also present with focal dystonia of the vocal cords (spasmodic dysphonia), or a segmental dystonia of trunk muscles, causing lateroflexion (Pisa sign) or anteroflexion (camptocormia) of the trunk. Note that a Pisa sign or camptocormia can also occur in PD or as a side-effect of drugs (mainly neuroleptics). A full differential diagnosis is presented in Table 5. The presence of early, fixed limb dystonia suggests a diagnosis CBD.
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