6 - clinical diagnosis of MS Flashcards
what is MS?
- acute localised, and chronic diffuse, inflammation of the CNS and subsequent demyelination of neurones, following the infiltration of immune cells across the BBB
what is the prevalence of MS in england?
1:500
briefly describe the steps leading to BBB destruction
initial insult — macrophage — cellular recruitment — chemokines — more recruitment — BBB destroyed
how does demyelination affect the impulse in nerves?
either delayed/variable or blocked — nerve may be sectioned or die = permanent disability
nerves a prone to variable conductivity with what?
temperature
how does optic neuritis present?
pain on eye movement, blurring of vision, red colour saturation
what is Uhtoff’s phenomenon?
the temporary worsening of MS symptoms caused by an increase in temperature — usually applied to optic neuritis
what brainstem symptoms are there in MS?
- vertigo
- slurred speech
- ataxia
- in coordination
- double vision
what is ataxia?
a term for a group of disorders that affect co-ordination, balance and speech
what spinal cord symptoms are there in MS?
- sensory — Lhermitte’s phenomenon
- motor — upper and/or lower limb weakness
- autonomic dysfunction — bladder, bowels, sexual dysfunction
what is Lhermitte’s phenomenon?
shooting pain down spinal cord on bending leg forward
dysarthria vs dysphagia
- dysarthria = difficulty speaking
- dysphagia = difficulty swallowing
describe the upper motor neurone signs seen in MS
- minimal muscle atrophy
- no fasciculations
- +ve Babinski sign
- hypertonia
- hyperreflexia
- clonus
is clonus present in UMN lesion or LMN?
UMN
what is the most important investigation in MS?
MRI
what are common sites of demyelination in MS?
- corpus callosum
- optic nerve
- cerebellum
- brainstem
- spinal
what is MRI used for in MS?
diagnose AND monitor disease activity
1/___ plaques causes a symptom or sign
only 1 in 10 to 15 — majority of lesions are asymptomatic
what % of MS patients have oligoclonal bands in CSF?
80%
visual evoked potentials in MS?
delayed in demyelination in the anterior visual pathways
what do somatosensory evoked potentials assess?
assesses the posterior column of the spinal cord, the brainstem and the cerebral cortex
any single investigation needs to be taken in the context of what?
patient’s age, history, examination findings, other illnesses and other investigations
what is required to diagnose MS?
TWO different relapses (space) at TWO different times (time)
—> DISSEMINATION IN SPACE AND TIME
what is an indication the disease has been going on for some time?
+ve oligoclonal bands
what are good and poor prognostic features in early MS?
what are the different types of MS?
what is considered a clinical relapse?
‘patient reported symptoms or objectively observed signs typical of an acute inflammatory demyelinating event in the CNS, current or historical, with duration of at least 24 hours, in the absence of fever or infection’
what is used to treat a relapse initially?
high dose corticosteroids either orally or iv (ie 1gml methyl prednisolone iv daily for 3 days) can accelerate recovery by reducing inflammatory activity/stabilising the BBB
what is progressive multi focal leukoenceophalopathy (PML)?
= a disease of the white matter of the brain, caused by a virus infection that targets cells that make myelin
- caused by JC virus
- 50% of population have antibodies
- 0.5-1% annual infection rate
- virus stays latent in various organs including kidneys. ling, spleen, bone marrow, B cells and tonsils
what 2 disease modifying agents (DMTs) have a 30% reduction in relapse rate?
beta interferon and glatiramer acetate
what 2 drugs have a 80% reduction in relapse rate?
alemtuzumab and natalizumab
how does alemtuzumab work?
monoclonal
targets B and T cells resulting in cell lysis
what do 1/600 patients taking natalizumab suffer from?
progressive multi focal leukoenceophalopathy
how odes natalizumab work?
monoclonal
prevents lymphocyte migration across the BBB
which DMTs are safe in pregnancy?
- interferons
- glatiramer
- natalizumab — but can cause thrombocytopenia in newborns
alemtuzumab is not safe for 4 months after treatment
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