Neurodegenerative diseases Flashcards
Neurodegenerative diseases
What is multiple sclerosis?
A chronic inflammatory multifocal, demyelinating disease of the CNS with unknown cause, leading to loss of myelin, and oligodendroglial and axonal pathology
(autoimmune disease attacking myelin)
What are the symptoms of MS?
Optic neuritis- blurred vision
Motor weakness
Sensory disturbances
Fatigue
Depends on the location of demyelination
What are the signs of MS?
Retrobulbar neuritis Papillitis Diplopia Nystagmus Internuclear ophthalmoplegia Intention tremor/ataxia/dysmetria Lhermitte's sign
What are the features of retrobulbar neuritis?
Pt reports blindness
Fundoscopy shows no abnormality
(Pt sees nothing, Dr sees nothing)
What are the features of papillitis?
Hyperaemia and oedema of the optic disc
What are the features of internuclear ophthalmoplegia
The affected eye has an inability to adduct and the contralateral eye can abduct, but with nystagmus
Pt will complain of horizontal diplopia
What is Lhermitte’s sign?
Shock radiating down spine upon neck flexion
What is the epidemiology of MS?
Latitude effect (more prevalent in higher latitude)
What are the risk factors of MS?
Psoriasis/AI conditions
HLA DLR B1*15
What are the types of MS?
Relapsing-remitting MS
Primary progressive MS
Secondary progressive MS
What is relapsing-remitting MS?
The patient will have symptomatic episodes of MS, whilst feeling fine between relapses
What is primary progressive MS?
There is a constant progression of worsening symptoms
What is secondary progressive MS?
The Pt starts off as RRMS, but developings into PPMS
What are the investigations for MS?
Diagnosis is based off of:
- Clinical Hx/Exam
- MRI
- CSF
- VEPs- visual evoked potential is delayed
How is MS diagnosed?- key features
Clinical diagnosis. No one specific test.
Need to tick the following:
- absence of alternative diagnosis
- disseminated in time- If you have one flare of MS- 1x CT showing demyelinating plaques, isn’t diagnostic. Need =>2 events.
- disseminated in space- affects different parts of the body
Which contrast is beneficial for an MRI scan of a MS Pt?
Gadolinium- light up areas of active inflammation
Shows active flares of MS- white shows acute
What should you expect to find in the CSF for MS?
Oligoclonal bands in the CSF, but not in the serum
Autoimmune so B cells involved in pathophysiology - secrete immunoglobulins which destroy myelin
- If found in serum = infection
- If only found in CSF = MS
What is myasthenia gravis? What causes it
Weakness in muscles through repeated use
Antibodies in the NMJ block ACh receptors, preventing the binding of ACh to its receptor –> can’t stimulate them after short amount of use
What are the 2 common types of myasthenia gravis antibodies?
AChR antibody
MuSK antibody
What are the signs of myasthenia gravis?
Muscles fatigue with use - Ptosis - Diplopia - Dysarthria - Dysphagia - SOB Muscles get fatigued so neuro exam may be normal at first but if muscles used repeatedly then they become abnormal
What are the signs of myasthenia gravis?
Fatiguable muscles
Normal reflexes
What is the epidemiology of myasthenia gravis?
Common in women<40 and men>60
What are the investigations of myasthenia gravis?
Bloods: anti-AChR, anti-MuSK
EMG- shows reducing amplitude of response
CT/MRI - check thymus
What are the associations of myasthenia gravis?
Thymic hyperplasia- 70%
Thyoma- 10%
What is Lambert-Eaton Myasthenic Syndrome?
Muscle weakness with improvement on use
Don’t work well at start but as axons increasingly fire more VGCCs open and the muscle is eventually stimulated
Affects VGCCs- antibodies bind and block so inhibit acetylcholine release and muscle contraction
What are the symptoms of LEMS?
Difficulty walking
Weakness in upper arm/shoulder
Similar to MG symptoms
Dry mouth, constipation, incontinence (autonomic)
What are the signs of LEMS?
Muscles get better with use
Hyporeflexia
What pathologies are associated with LEMS?
- Small cell lung cancer- LEMS can be a paraneoplastic syndrome
- Autoimmune conditions
What are the investigations for LEMS?
Bloods: anti-VGCC
EMG
CT/MRI
What is motor neurone disease (AKA amyotrophic lateral sclerosis)?
Chronic neurodegenerative condition causing muscle wasting, paralysis, and death
What are the symptoms of MND?
Progressive muscle weakness –> wheelchair-bound
Impaired swallowing and speech (bulbar signs)
Spastic weakness and paralysis in skeletal muscle
Respiratory failure (weak intercostals)- cause of death usually muscle in chest wall
Sparing of the oculomotor, sensory, and autonomic function (aka bowel, bladder, sexual function intact)
Does MND present with UMN or LMN signs?
Both UMN and LMN signs
What are the signs of MND?
UMN + LMN signs- classic combination
Wasting of thenar muscles
Wasting of bulbar muscles of the tongue
What is the cause of MND?
Ubiquinated proteins in the motor neurons kills the cells- accumulation of misfolded proteins –> apoptosis
Leads to death of corticospinal tracts
97% of Pts have ubiquitin inclusions positive for TDP-43
What are the investigations for MND?
Clinical diagnosis
Can do the following: EMG- see fasciculations CT/MRI B12/folate HIV Lyme disease seroloy
These are done to rule out other causes
What are the 4 types of MND?
Progressive muscular atrophy (LMN)
Progressive bulbar palsy (CN)
Pseudobulbar palsy (UMN)
Primary lateral sclerosis (UMN)
Which nerves are affected in progressive muscular atrophy and what is the typical presentation?
LMN only
LMN signs only- flail arm/foot syndrome
Which nerves are affected in progressive bulbar palsy
and what is the typical presentation?
CN XI-XII
Flacid fasciculations of tongue
Absent jaw jerk
Nasal voice (Donald Duck)