Degenerative Diseases with Parkinsonism
<DL
Corticobasal degeneration (CBD) is classified as an akinetic rigid
movement disorder classically consisting of progessive asymmetric
rigidity and apraxia with late development of cognitive decline.
However, a wider clinical spectrum, including dementia as an early
finding, is possible. Postmortem gross features include asymmetrical
cortical atrophy of the posterior frontal, parietal, and the peri-Rolandic
cortex contralateral to the limbs most severly affected in life. Histologic
findings include focal/asymmetric neocortical atrophy, which
predominantly involves the frontoparietal region in most cases, and
ballooned achromatic neurons. Basal ganglia and nigral degeneration
are often but not always present. The etiology is unknown but
molecular studies indicate glial and neuronal accumulation of the tau
protein in affected areas. There is substantial pathological and clinical
overlap with other neurodegenerative disorders such as CreutzfeldJakob disease, progessive supranuclear palsy, Alzheimer disease, and
Pick disease. This can make unequivocal diagnosis difficult. (Boeve,
2007)
Multiple system atrophy (MSA) has features that overlap striatonigral
degeneration, olivopontocerebellar atrophy, and Shy-Drager syndrome.
Most patients with MSA exhibit symptoms similar to Parkinson disease.
The clinical appearance is that of a sporadic, progressive, adult-onset
disorder with autonomic dysfunction (orthostatic hypotension or urinary
incontinence/retention, parkinsonism cerebellar dysfunction, and
corticospinal tract signs. MSA is characterized microscopically by the
appearance of glial cytoplasmic inclusions. (Boeve, 2007)
Progressive supranuclear palsy (PSP) is classically marked by a
supranuclear gaze palsy along with rigidity, but patients with this
disorder may present with dementia that appears similar to Alzheimer
disease. Clinical features include a gradually progressive onset at age
40 or later along with vertical supranuclear palsy and prominent
postural instability with falls in the first year of disease onset, and no
evidence of other diseases that could explain the foregoing features, as
indicated by mandatory exclusion criteria. The pathologic diagnosis is
made by the microscopic findings of globose neurofibrillary tangles and
variable neuron loss with gliosis of the globus pallidus, subthalamic
nucleus, periaqueductal grey matter of pons, and substantia nigra.
Mutant tau protein has been found in association with PSP. (Boeve,
2007)