Multiple sclerosis Flashcards
Define multiple sclerosis?
Inflammatory demyelinating disease of the CNS – discrete plaques of demyelination occur at multiple CNS sites, from T-cell mediated immune response
summarise the epidemiology of multiple sclerosis?
UK prevalence: 1/1000
2 x as common in FEMALES
Age of presentation: 20-40 yrs
what are the 4 types of multiple sclerosis?
Relapsing-Remitting MS
- COMMONEST form
- Clinical attacks of demyelination with poor healing in between attacks
Clinically Isolated Syndrome
- Single clinical attack of demyelination
- The attack in itself does NOT count as MS
- 10-50% progress to develop MS
Primary Progressive MS
- Steady accumulation of disability with NO relapsing-remitting pattern
Marburg Variant
- Severe fulminant variant of MS leading to advanced disability or death within weeks
what are the risk factors for MS?
Females
EBV exposure
Prenatal vitamin D levels
Smoking
Other AIs
IL7RA and IL2RA associated with increased risk of MS
describe the aetiology of MS
UNKNOWN
Autoimmune basis with potential environmental trigger in genetically susceptible individual
Immune-mediated damage to myelin sheaths results in impaired axonal conduction
Deposition of beta amyloid plaques and tau protein fibres tangles
what is uhtoff’s sign?
worsening of neurological symptoms as the body gets overheated from hot weather, exercise, saunas, hot tubs etc.
what is Lhermitte’s/ Barber seat Sign?
an electrical sensation that runs down the back and into the limbs when the neck is flexed
what are the signs of MS on physical examination?
Optic Neuritis
- Impaired visual acuity (MOST COMMON)
- Loss of coloured vision
Visual Field Testing
- Central scotoma (if optic nerve is affected)
- Scotoma = a blind spot in the normal visual field
- Field defects (if optic radiations are affected)
Relative Afferent Pupillary Defect (RAPD)
Internuclear Ophthalmoplegia
- Lateral horizontal gaze causes failure of adduction of the contralateral eye
- Indicates lesion of the contralateral medial longitudinal fasciculus
Sensory
- Paraesthesia
Motor
- UMN signs
Cerebellar
- Limb ataxia (intention tremor, past-pointing, dysmetria)
- Dysdiadochokinesia
- Ataxic wide-based gait
- Scanning speech
what is the typical presentation of MS?
Different neuro symp (optic neuritis - painful blurred vis - is common) sep by time and oligoclonal bands in CSF which aint in serum
what gives a better prognosis of MS?
- Onset under 25 yrs
- Optic neuritis or sensory symp at first presentation
- Long interval between relapses (>1yr)
- Few lesions on MRI
- Full recovery from previous relapses
- Female
What are the presenting symptoms of MS?
What criteria is the diagnosis of MS based on?
Diagnosis is based on the finding of two or more CNS lesions with corresponding symptoms,separated in time andspace- McDONALD CRITERIA
what are the investigations for MS?
MRI Brain, Cervical and Thoracic Spine (with gadolinium) – shows lesions – some are active and some are older
Do a FBC and blood test to see if met, TSH and vitB is all norm
Lumbar Puncture
- Microscopy - exclude infection/inflammatory causes
- CSF electrophoresis shows unmatched oligoclonal bands – basically present in the CSF and not in the serum
What does CSF electrophoresis show in MS?
unmatched oligoclonal bands – basically present in the CSF and not in the serum
what does the MRI brain, cervical and thoracic spine with gadolinium show?
shows lesions – some are active and some are older
Plaques can be identified
Gadolinium enhancement shows active lesions (but not all lesions are enhanced with Gadolinium for a diagnosis of MS)
dissemination in time requires demonstration of new lesions compared to previous imaging.
During an acute attack, inflammation makes the blood brain barrier leaky-> allows immune cells into the CNS (normally brain is immune privileged). The GAD contrast as it will also cross the barrier during periods of acute inflammation.
This lights up any active lesions, and old lesions remain darker, so can see what’s old and what is new.
After an acute attack the blood brain barrier is leaky for around 2 to 6 weeks, so anything that lights up is at most 6 weeks old.
