Parkinson’s Disease and Parkinsonism: Summary
1. Parkinsonism is a syndrome with bradykinesia (slowness), tremor, rigidity, and postural
instability. It can be caused by Parkinson’s disease (PD) or other disorders. 2. All parkinsonian
disorders involve loss of dopamine neurons in the substantia nigra. 3. Main Types: - Parkinson’s
Disease (PD): α-synuclein builds up in neurons (Lewy bodies). Symptoms: tremor, rigidity, slow
movements. Good response to levodopa. - Multiple System Atrophy (MSA): α-synuclein builds in
glial cells. Causes parkinsonism plus autonomic failure and cerebellar problems. Poor levodopa
response. - Progressive Supranuclear Palsy (PSP): tau protein builds up in neurons & glia.
Symptoms: early falls, eye movement problems, speech issues, dementia. 4. Other forms:
Corticobasal Degeneration, Chronic Traumatic Encephalopathy, Guam Parkinson-Dementia, and
TDP-43 related parkinsonism. 5. Progression (Braak Staging): Pathology starts in olfactory
bulb/brainstem → substantia nigra → cortex. Explains early non-motor signs (sleep problems,
constipation, loss of smell). 6. Conclusion: Parkinsonism is not just PD, but a group of disorders
classified by molecular pathology (α-synuclein, tau, TDP-43). All share dopamine neuron
degeneration.