Degenerative Diseases of the CNS Flashcards
What are some common features of neurodegenerative diseases?
- Aetiology often unknown
- Usually late onset
- Gradual progression
- Neuronal loss
What is dementia?
A neurodegenerative disease resulting in progressive impairment of MULTIPLE domains of cognitive functioning - resulting in LOSS OF ACQUIRED SKILLS and interference in occupational and social role
What are the main causes of dementia?
- Alzheimers
- Vascular
- Lewy body (old patients)
- Frontotemporal (younger patients)
- Creutzfeldt-Jakob Disease
- If dementia is young onset (<65yrs), other causes such as alcohol and genetics account for a higher percentage of cases
What are some of the treatable causes of dementia?
- Vitamin B12 deficiency
- Endocrine: thyroid disease
- Infection: HIV, syphilis
Important patient history questions for dementia diagnosis? Clinical examinations?
History:
- Type of deficit
- Progression
- FH / risk factors
Examination:
- Cognitive function
- Neurological / vascular
Investigations for suspected dementia?
- Routine: bloods / CT / MRI (rule out hydrocephalus / haematoma)
- others: CSF, EEG, functional imaging, genetics
What are some of the domains of cognitive functions that may be affected by dementia?
- Memory
- Attention
- Language
- Visuospatial
- Behaviour
- Emotion
- Executive function
- Apraxias (ability to plan movement)
- Agnosias (processing sensory info)
What screening tests are used to help diagnose dementia?
- Mini-mental (MMSE)
- Montreal (MOCA)
What are some signs that help with determining which of the different causes of dementia a patient is suffering from?
Speed of progression
- Rapid (CJD)
- Stepwise (vascular)
Other neurological signs:
- Abnormal movements (Huntingtons)
- Parkinsonism (Lewy Body)
- Myoclonus (CJD)
What is the most common cause of dementia?
- Alzheimer’s disease
Risk factors for developing Alzheimer’s?
- Genetic
- Smoking
- Diet
- Alcohol
- Exercise
Signs of frontotemporal dementia?
- Early change in personality / behaviour
- Change in eating habits
- Early dysphasia
- Memory / visuospatial ability relatively preserved
Signs of vascular dementia?
- Mixed picture symptoms-wise (motor + cognitive)
- Stepwise progression of disease
Treatment of dementia? (broad)
Non-pharma:
- Occupational therapy / social work
Pharmacological:
- Insomnia meds
- Behavior (antipsychotics)
- Antidepressants
Alzheimer’s (+/- Lewy Body) dementia specific treatment?
- Cholinesterase inhibitors (Donepezil / Rivastigmine)
- NMDA antagonist
Specific treatment of frontotemporal / Vascular dementia?
Frontotemporal:
- None
Vascular:
- None supported by robust evidence
What is Parkinsonism?
A clinical syndrome with two or more of:
- Bradykinesia (slow movement)
- Rigidity
- Tremors
- Postural instability
Pathophysiology of Parkinsons?
- Degeneration of dopaminergic neurones of the basal ganglia (esp. substantia nigra)
Causes of Parkinsons?
- Idiopathic (dementia with Lewy Bodies)
- Drug induced (eg. dopamine antagonists)
- Vascular Parkinsons
Clinical signs indicating Parkinsons?
Bradykinesia + tremor / rigidity / postural instability
- Supported by asymmetric rest tremor and a good response to dopamine replacement therapy
What are some signs that would NOT SUPPORT a Parkinson’s diagnosis?
- Rapid progression
- Symmetrical (tremors etc.)
- Poor response to dopamine replacement therapy
- Early falls
- Early dementia
What investigation can be good for diagnosing / staging Parkinsons? What does it measure?
- Dopamine Transporter SPECT (Single-photon emission computed tomography)
- Measures the efficiency of dopamine transporters in the presynaptic cleft that bring in dopamine for re-use or degradation (best seen at caudate and putamen)
Treatment of early Parkinson’s disease?
Increase amount of available dopamine (inhibit breakdown enzymes):
- COMT inhibitors
- MAO-B inhibitors
Dopamine agonists
- Ropinirole / Pramipexole
What are some late complications that can occur with Parkinson’s disease?
Drug induced:
- Motor Fluctuations (levodopa wears off)
- Dyskinesias (involuntary movements - levodopa)
- Psychiatric (hallucinations / impulse control)
Non-drug induced:
- Depression
- Dementia
- Speech / swallow / balance issues
