Multiple Sclerosis Flashcards
What is the epidemiology of MS?
More common the further from the equator you are
Rare in Africa, Asia
Twice as common in women
Mean age of onset 20-45
What is the aetiology and pathophysiology of MS?
Discrete plaques of demyelination occurs at multiple CNS sites from a T cell mediated immune response
Triggers are unknown
Sunlight may have a preventative action - early exposure to sun/vit D is important; UV exposure in those with established disease relates to fewer new lesions on MRI
Normally macrophages cannot easily cross BBB but in Ms they exhibit glycoprotein α4ß1 allowing them to adhere to and cross the endothelium
Antibodies to myelin basic protein can be found early in the disease
Lesions most commonly occur at the optic nerves, periventricular, brainstem and cerebellar connections
Demyelination heals poorly:
Can cause relapsing and remitting symptoms
Conduction loss or blockage is probably to blame for most of the symptoms of MS
Over an extended period → axonal loss and clinically progressive symptoms
What are the 4 types of progression in MS?
Relapsing remitting (most common) - unpredictable attacks whhick may or may not leave permanent deficits followed by periods of remission
Secondary progressive - initial relapsing-remitting then suddenly begins to decline without periods of remission
Primary progressive (10-20%) - steady increase in disability without attacks
Progressive relapsing (<10%) - steady decline since onset with superimposed attacks
How might MS present?
Can be almost any neurological sign - dependent on areas of demyelination
Eye signs, UMN signs, sensory signs, autonomic defects, cerebellar signs, cognitive decline, systemic features
What are some eye signs?
Optic neuropathy:
Usually unilateral
Pain on eye movement
Rapid loss of central vision
Optic disc swelling, pupillary defects, diplopia, hemianopia
What are some UMN signs?
Spasticity Hyperreflexia Hypertonia Positive Babinski Weakness
What are some autonomic signs?
Urinary incontinence
Constipation
Sexual dysfunction
What are some cerebellar signs?
Truncal and limb ataxia Intention tremor Coordination problems Nystagmus Monotonous speech Falls
What are some sensory signs?
Parasthesia - burning/tingling in limbs
Numbness
Reduced vibration sense
Trigeminal neuralgia
What are some cognitive changes?
Amnesia Aphasia Altered mood Personality change Reduced functioning
What are some systemic signs?
Pyrexia
N+V
Seizures
What are some early indications for poor prognosis?
Older Male Motor signs on onset Many early relapses Many MRI lesions Axonal loss
What is Uthoff’s phenomena?
Signs (i.e. vision) worse on hot days/post exercise as heat slows condition in nerve fibres
What is Lhermitte’s sign?
Aka ‘barber chair phenomena’
On voluntary flexing of the head there is an electric shock sensation travelling down the spine to the limbs
How do you diagnose MS?
McDonald criteria for diagnosing MS
Uses number of attacks and objective clinical lesions ± MRI evidence to identify MS and its type:
At least 1 ‘attack’ + multiple plaques on MRI OR
A single attack/progressive MS + multiple plaques on MRI + other evidence (oligoclonal bands, VEPs etc)
(‘Lesions disseminated in time and space’ and unattributable to other causes)
What will MRI show in MS?
85% of cases will show plaques so is best test out there, even though diagnosis still should be combined with a clinical picture
Plaques will be 2-10mm and show up as white (most commonly in the areas mentioned - e.g. optic nerves)
What will VEPs show?
Visual evoked potentials
Can detect lesions in visual pathways
Patient has EEG probes on the skull → measure brain response to visual stimuli by timing the duration between image shown and brain response measured → if delayed = some kind of optic nerve lesion
What are oligocloncal bands?
Bands of IgG in CSF on electrophoresis
If not present in serum, suggest CNS inflammation
What is the non-pharmacological management of MS?
Encourage stress free life if possible (as can reduce chance of new lesions)
Minimize disability – OT, PT, diet, increase vit D exposure/supplement
How are MS relapses managed?
Methylprednisolone
500mg PO OD for 5 days OR
Up to 1 g IV OD for up to 3-5 days
Shortens acute relapses
Use sparingly i.e. <2x/yr
No change to prognosis
Manage any other symptoms as appropriate (e.g. constipation, breathing etc)
What is typically used in the long term management of MS?
Beta interferons – INF-1ß and -1α (given IM or SC) FREQUENCY
Naturally produced by body to reduce inflammation after an immune response
Decreases relapse by 30% in active relapse-remitting MS; decreases lesion accumulation on MRI
What other agents can be used in MS?
Monoclonal antibodies:
Alemtuzumab - acts on T cells in relapsing-remitting MS
Natalizumab – acts on VLA-4 receptors that allow immune cells to cross the BBB; decreases relapse and MRI lesions in relapse-remitting MS
Azathioprine - for relapse-remitting
What else is important in the management of MS?
Treat all infections promptly as they are known to exacerbate
For spasticity – Baclofen, diazepam, dantrolene, tizanidine, Sativex (endocannibinoid modulator)
For tremor – Botulinum toxin type A
For urgency/frequency – teach intermittent self-catheterisation, tolterodine
