parkinsonism

Almost half of all movement disorders is Parkinsonism. This is manifested by any combination of 4 cardinal features: resting tremor, bradykinesia (slowness in movement), rigidity (stiffness) and gait/postural instability. At least 2 of these features need to be present with one being resting tremor or bradykinesia before the diagnosis of parkinsonism is made.

There are several causes of parkinsonism: primary, secondary, parkinson-plus, and heredo-degenerative disorders. Primary parkinsonism (Parkinson’s disease) refers to a progressive disorder of unclear etiology and the diagnosis is often made by excluding other causes of parkinsonism. For this reason, it is also called “idiopathic” PD. It is probably the most common type of parkinsonism encountered by a neurologist.

Secondary parkinsonism refers to disorders with an identifiable cause such as drug-induced parkinsonism (from intake of dopamine receptor blocking agents such as antipsychotic and anti-emetic drugs), or parkinsonism resulting from a stroke, infection, or tumor in and area of the basal ganglia.
Parkinson-plus syndromes are also progressive neurodegenerative disorders with parkinsonism as their main but not the only feature. Examples of parkinson-plus disorders are: progressive supranuclear palsy (with early dementia, vertical gaze palsy and early, frequent falls), multiple systems atrophy (with lack of tremor, more prominent cerebellar features such as ataxia and incoordination, significant autonomic dysfunction such as urinary incontinence, erectile dysfunction or orthostatic hypotension) and cortico-basal-ganglionic degeneration or cortico-basal-degeneration (presenting with early dementia, limb dystonia and “alien limb phenomenon”—where the limb performs autonomous movements). Finally, other neurodegenerative disorders can also present with parkinsonism. The main difference between this group (compared to the parkinson-plus) of disorders is that parkinsonism is not their most prominent feature. For example, Alzheimer’s disease is primarily a neurodegenerative disorder of memory dysfunction but parkinsonism can occur at the later stages of the illness.