Parkinson's Flashcards
What is Parkinson’s disease (PD) definition?
Parkinson’s Disease (PD) is a neurodegenerative disorder characterised by loss of dopaminergic neurones within the substantia nigra pars compacta (SNPC) of the basal ganglia (nigrostriatal pathway).
Epidemiology of PD
- Parkinson’s Disease is the second most common neurodegenerative disease (after Alzheimer’s Disease)
- It’s progressive, adult-onset disease, and it gets more common with age
- Prevalence of 1% in those aged 60-70 and up to 1-3% in those ≥80 years old
- M>F
- 3% > 65 yr.
RFs for PD
- Age:prevalence of 1% in those aged 60-70 and up to 1-3% in those ≥80 years old
- Gender:males are 1.5 times more likely than females to develop PD
- Family History
What is PD?
- Parkinson’s disease is a condition where there is a progressive reduction of dopamine in the basal ganglia of the brain, leading to disorders of movement.
Key genes involved in Parkinson’s ?
Those which code for α-synuclein and the ubiquitin-protease system.
the result is a loss of transmission between the basal ganglia, thalamus, and motor cortex, resulting in unimpaired control of voluntary movements.
What is the histological hallmark of PD?
eosinophilic inclusion bodies consisting of misfolded α-synuclein in the dopaminergic neurones of the SNPC called Lewy bodies.
What are the significance of these inclusion bodies
misfolded α-synuclein may spread to neighbouring brain regions in a prion-like fashion.
What is the basic pathophysiology of PDs
There is diminished substantia nigra
Susceptibility factors + Inherited factors + Parkinsons Genes > Cell loss in substantia Nigra < Risk Factors + Environmental factors + Toxin induced
‘Parkinsonism’ symptoms
- Bradykinesia
- Tremor (at rest, maybe unilateral)
- Rigidity (Pain, problems with turning in bed)
- Postural instability
- non motor brain functions
What other conditions is Parkinsons associated with?
- lewy body dementia
- multiple system atrophy
- progressive supranuclear palsy
- corticobasal degeneration
What do PD symptoms usually start and then later become?
Start unilaterally
Then become bilateral later in the disease course
Bradykinesia symptoms
- Slow movements
- Difficulty initiating movement
- Shuffling gait with reduced arm swing
- Problems with doing up buttons, keyboard etc
- Writing smaller
- Walking deteriorated: Small stepped, dragging one foot etc
Tremor symptoms
- Resting ‘pill-rolling’ (4-6 Hz) tremor
- At rest - better with voluntary movement
- May be unilateral
Rigidity symptoms
Cogwheel rigidity occurs due to a tremor superimposed on a rigid movement
Lead- pipe rigidity describes stiffness throughout the entire movement
Pain
Problems with turning in bed
Other features of motor symptoms
- Micrographia - (abnormally small, cramped handwriting)
- Hypomimia (reduced degree of facial expression)
- Postural instability
Non motor symptoms of PD
- Anosmia (smell blindness)
- Sleep disturbance: REM sleep is impaired
- Psychiatric symptoms
- Depression
- Anxiety
- Dementia: usually develops after motor symptoms, unlike in Lewy-body dementia
- Constipation
- Increased urinary frequency
- Urinary incontinence not typical
What does the increased pressure of the hydrocephalus in PD cause?
Magnetic gait
Incontinece
Dementia
What symptoms are not found in PD?
- Incontinence
- Dementia
- Symmetry
- Early falls
These especially not found in early PD
PD investigations
- PD is a clinical diagnosis: it should be suspected in a patient who has bradykinesia and atleastoneofthe following:
- Tremor
- Rigidity
- Postural instability
What investigations can you consider for PD
- MRI brain:may help exclude other causes of neurological disease but should not be used to diagnose PD
- SPECT (DaT scan):single-photon emission computed tomography (SPECT) will show reduced dopamine uptake in the basal ganglia
DDs FOR Parkinson
Benign Essential Tremor
Benign Essential Tremor - Treatment
- Take it seriously!
- 1/3 of pat have to re-train!
- Beta-blockers
Up to 100 mg bd
Contraindicated in pat with asthma or diabetes - Primidone
Start off with low doses - Others
Gabapentin, clonazepam
1st line management for PDs
Motor symptoms affecting quality of life
-
Levodopa + decarboxylase inhibitor
- Co-benyldopa (levodopa and benserazide)
- Co-careldopa (levodopa and carbidopa)
- Boosts dopamine levels and decarboxylase inhibitor prevents levodopa breakdown before it reaches the brain
1st line medications for motor symptoms not affecting quality of life
A choice of one of the following:
-
Dopamine agonist(non-ergot derived)
- Pramipexole, ropinirole
- Ergot derived medications (e.g. bromocriptine) should be avoided as they are associated with cardiac and pulmonary fibrosis
-
Monoamine oxidase B inhibitor
- Selegiline, rasagiline
- Stop breakdown of circulating dopamine
- Levodopa + decarboxylase inhibitor
