Parkinson’s Disease is an age-related chronic, progressive neurodegenerative disorder that primarily affects movement is the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (midbrain). which is responsible for controlling movement and coordination. This condition is best known for how it affects muscle control, balance and movement, it can also cause a wide range of other effects on your senses, thinking ability, mental health and more..This leads to:
Formation of Lewy bodies, abnormal intracellular aggregates made of the protein alpha-synuclein, which are toxic to neurons.
Dopamine depletion in the striatum, a key component of the basal ganglia, which regulates voluntary motor control.
Parkinson’s disease
Major Pathological Processes:
Pathology
Mitochondrial dysfunction – Impaired complex I of ETC.
Protein aggregation – Due to dysfunctional autophagy and lysosomal path
What is the difference between Parkinson’s disease vs. parkinsonism?
“Parkinsonism” is an umbrella term that describes Parkinson’s disease and conditions with similar symptoms. It can refer not only to Parkinson’s disease but also to other conditions like multiple system atrophy or corticobasal degeneration.
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Parkinson’s disease
Definition
A specific neurodegenerative disease caused primarily by dopamine deficiency in the substantia nigra.
Cause
Idiopathic (unknown exact cause), often linked to loss of dopaminergic neurons and Lewy body formation.
Underlying Pathology
Alpha-synuclein aggregation (Lewy bodies), dopamine neuron loss in substantia nigra.
Typically shows good improvement, especially early in disease.
Disease Progression
Slowly progressive, over many years.
Non-Motor Symptoms
Present (e.g., loss of smell, depression, REM sleep behavior disorder).
Examples
Idiopathic Parkinson’s Disease (only one type).
Neuroimaging
DaTscan: Decreased dopamine transporter uptake.
Treatment
Levodopa, dopamine agonists, MAO-B inhibitors, DBS in later stages.
Prognosis
Generally better, long-term management possible.
Parkinsonism (Parkinsonian Syndromes)
Definition
A broad clinical syndrome with signs similar to PD (e.g., tremor, rigidity), but can have many different causes.
Cause
Can be due to: <ul><li>Other neurodegenerative diseases (atypical Parkinsonism)</li><li>Medications (drug-induced)</li><li>Stroke, trauma, toxins</li></ul>
Underlying Pathology
Depends on cause: <ul><li>No Lewy bodies in drug-induced forms</li><li>Different proteinopathies in atypical types (e.g., tau in PSP)</li></ul>
Motor Symptoms
Similar motor signs, but often: <ul><li>More symmetric</li><li>More rapid progression</li><li>Less tremor</li></ul>
Response to Levodopa
Poor or minimal response in most forms of secondary or atypical Parkinsonism.
Disease Progression
Often faster progression (especially atypical forms like PSP or MSA).
Non-Motor Symptoms
May be less common or more rapidly developing cognitive/neurological issues.