MS & Treatment Flashcards
(33 cards)
What is MS?
Multiple episodes of the same or different neurological symptoms separated by periods of remission.
MS follows a very unpredictable and variable disease course
from relatively benign forms to rapidly progressive forms.
Although neurological recovery does occur during the early
stages, the majority of MS cases develop chronic
progressive symptoms eventually.
What is the incidence & prevalence of MS?
3-7 new cases per year per 100,000 population
100-120 per 100,000 are living with MS
= 50 - 60,000 people in England and Wales
Disease course
- Relapsing/remitting MS
– 80% of people at onset - Secondary progressive MS
– about 50% of those with relapsing/remitting MS develop secondary
progressive MS during the first 10 years of their illness - Primary progressive MS
– 10–15% of people at onset
What are the diverse symptoms of MS?
Blind areas in L eye
Weakness / paralysis in legs
Numbness in L hand
Loss of senses of balance and taste
Hot baths: “a nightmare, everything goes haywire”
Constant tingling / fizzing in feet
With eyes shut, sees dots / sparks of light
Eye movement: brighter, bigger flashes
Bending neck causes electric shock from waist to toes
“I used to have a relapse and get back to normal, but
now I don’t get back to normal”
What causes symptoms of MS?
- Demyelination
- Loss of myelin sheaths (‘demyelination’)
- Inflammation
- Inflammation in the brain and spinal cord
- Degeneration
- Axonal damage and neuronal loss
Consequences:
a) acute loss of function
b) repairable damage
c) chronic damage
Demyelination
Most characteristic feature of MS pathology is the demyelinated plaque.
Sharply demarcated lesions are suggestive of chronic MS.
Usually centred around one or more blood vessels.
Myelin sheaths are completely lost in the plaques.
CNS lesion in MS is the demyelinated plaque which can be identified at post-mortem & can occur at any site where myelin sheaths are
present.
How does demyelination cause MS?
A conduction block meaning that nerve impulses cannot propagate along the axon of the nerve cell
What is remyelination?
Restoration of the conduction (remylination= can take days to occur)
In the early stages of MS, rapid and extensive remyelination occurs, to the point complete remyelination of lesions can occur.
In MS remyelination is relatively common but eventually fails.
If remyelination is effective during the early stages of MS why then
does it fail as the disease progresses?
Repair strategies could try to repopulate the CNS with cells that can
produce myelin (oligodendrocytes).
Restoration of conduction= AKA remission
What is remission?
Restoration of conduction
This can take days usually to occur. As sodium channel expression also needs to occur
Clinical feature, primary cause, pathology
Clinical Feature: Relapse, Remission, Positive Phenomena (Uhtoff’s Lhermitte’s), Progression.
Causes & Pathology:
Relapse-> Conduction block -> Demyelination & inflammation
Remission-> Restoration of conduction -> Remylination & Inflammation
Positive phenomena -> Hyperexcitability (ectopic impulses/ mochanosensitivity)-> Demyelination
Progression -> Persistent loss of conduction -> Demyelination & Axonal loss
How does inflammation cause acute MS?
- Initial lesion induces release of cytokines & chemokines (2,3) which attract:
– T cells (myelin antigen specific)
– B cells
– Macrophages (4) - Cells can’t leave the site of lesion (adhere)
Inflammation & MS
Inflammatory infiltrates mainly consist of lymphocytes & macrophages
Active MS plaques characterised by lymphocyte infiltration.
Active plaques also contain numerous macrophages containing myelin at various stages of degradation.
myelin whorls
myelin proteins
neutral lipids
inflammation alone may be sufficient to cause significant clinical deficits without demyelination
How does Axonal degeneration cause acute MS?
- In primary progressive MS, 5% of the spinal cord cross sectional area can be lost annually
- Chronic lesions in paralysed MS patients show an average loss of 68% (45-84%) of axons
- Axonal degeneration is a major cause of irreversible deficit with no
effective therapy
MS probably has a silent stage of axonal degeneration, which lasts for 10-12 years in relapsing-remitting patients. Because inflammatory attacks occur during this period it should be possible to start neuroprotective therapies early enough
Therapeutic opportunities in MS
- Inflammation in the brain and spinal cord - STOPPABLE
- Loss of myelin sheaths (‘demyelination’)- REPAIRABLE
- Axonal damage & neuronal loss- IRREPAIRABLE BUT PREVENTABLE
MS symptoms
- Spasticity/spasms
- Bladder/bowel symptoms (incontinence)
- Pain
- Cognitive symptoms
- Emotionalism
- Depression
- Anxiety
- Fatigue
- Walking
MS symptoms
- Spasticity/spasms
- Bladder/bowel symptoms (incontinence)
- Pain
- Cognitive symptoms
- Emotionalism
- Depression
- Anxiety
- Fatigue
- Walking
Management of MS
- Recommended
– Exercise
– Offer amantadine to treat fatigue, mindfulness
– Consider baclofen or gabapentin as first line treatment to treat spasticity
– Consider amitriptyline to treat emotional lability
– Neuropathic pain management
Current treatments for MS
- Acute episode:
– First choice: high dose corticosteroid - Oral methylprednisolone, 500 mg daily, 5 days
– Risks with steroids?
– If considering iv steroid, then some of the DMARDs may be used
instead.
Past treatments for MS (No longer recommended)
Relapsing-remitting and secondary progressive MS:
– linoleic acid 17-23g/day (sunflower, corn, soya, safflower oils)
– azathioprine (immunosuppressant)
– mitoxantrone (antineoplastic agent), may extend the time between
relapses
– intravenous immunoglobulin
– plasma exchange
– intermittent (4-monthly) short (1–9 days) courses of high dose
methylprednisolone.
Disease-modifying treatments
- Alemtuzamab
- Beta interferons & glatiramer acetate
- Cladribine
- Dimethyl fumarate
- Fingolimod
- Natalizumab
- Ocrelizumab
- Teriflunomide
- Back to management if they don’t work
Alemtuzumab (Lemtrada)
– Monoclonal antibody, binds CD52, a protein found on lymphocytes
– Approved in Sept 2013 as a first line treatment
– 12 mg/day by iv infusion for 2 treatment courses
* 5 consecutive days
* 12 months later 2nd course of 3 consecutive days
– £7045 per 12 mg vial (£56,360 over 2 years)
– Significant complications possible, include susceptibility to viral, bacterial & fungal infections due to immunosuppressant properties.
Interferons
- normally produced by fibroblasts as part of the immunological
response to viral and non-viral antigens - pro-inflammatory factor, activating cytokine and chemokine
production, by activating macrophages and natural killer
lymphocytes. Enhancing MHC classes I and II. - however acts as an anti-inflammatory and immunosuppressant
agent in some circumstances, e.g. MS, where it Induces the
production of anti-inflammatory factors - mechanism of action poorly understood but considered to reduce
inflammation (& possibly promote remyelination) - reduces the rate of relapse of MS.
- Clinically effective
Glatiramer acetate
- Synthetic amino acid/peptide mixture
– Glutamate, Alanine, Lysine, Tyrosine - unknown mechanism of action
– myelin decoy? - Proposed to be an immunomodulatory drug.
– Shifts T-cell population from pro-inflammatory Th1 to regulatory
Th2 that suppresses inflammatory response - Clinically effective
NICE TA527 covers interferons and glatiramer
– interferon beta-1a (Avonex and Rebif) – recommended
– Interferon beta-1b (Extavia) – recommended option for severe MS
– interferon beta-1b (Betaferon) –not recommended (too expensive
for benefits)
– Glatiramer acetate (Copaxone) – recommended
– Licensed in UK under commercial arrangements of the companies
with NHS, i.e. discount.
– Patients originally on betaferon are not prevented from staying on
this medication
