Multiple Sclerosis Flashcards
Briefly describe MS
An immune mediated inflammatory condition. Plaques of demyelination occur in the CNS that are disseminated in space and time (ie occurring at multiple sites and with 30 days between attacks)
Recurrent episodes of demyelination can lead to what?
Degeneration of nerves and permanent deficit
Is MS more common in men or women?
3 times more common in women
Between what age group is it most commonly diagnosed?
20-40
Is MS more common in higher or lower latitudes?
Higher
What is the cause of MS?
Unknown - likely combination of genetic and environmental
Likely abnormal immune response to environmental triggers in genetically predisposed.
Genetic: female, genes encoding for HLA-DR2 (a specific immune molecule)- used to identify and bind to foreign molecules
Environmental: infections, vit d deficiency
What are the 3 main patterns of presentation?
Relapsing and remitting
Secondary progressive
Primary progressive
Which form of MS is most common?
Relapsing and remitting
Accounts for approximately 85%
Describe relapsing and remitting MS
Acute attacks lasting 1-2 months followed by periods of remission.
Symptoms experienced previously may come back, or new symptoms
Describe secondary progressive MS
With time, remission becomes incomplete, so disability accumulates
Signs and symptoms between relapses
Around 65% of people with relapsing remitting disease go on to develop secondary progressive within 15 years
Describe primary progressive disease
Progressive deterioration from onset
More common in elderly
Accounts for 10%
How does MS commonly present?
Usually monosymptomatic - approximately 20% present with unilateral optic neuritis
Corticospinal tract and bladder involvement are common
How does optic neuritis present?
Unilateral
Pain on eye movement
Sudden loss in vision, partial or complete (usually central visual loss)
Sudden blurring or foggy vision
Loss of colour vision - colours appearing washed out, particularly red (red desaturation)
Reduced contrast sensitivity
Transient worsening of vision with increase in body temperature (Uhthoff’s phenomenon)
Pupil afferent defect
What do symptoms worsen with?
Heat e.g hot bath or exercise
What is a common non specific feature of MS
Significant lethargy
What sensory features are seen in MS?
Pins and needles
Numbness
Reduced vibration sense
Trigeminal neuralgia
Patchy sensory loss
What motor symptoms are seen in MS?
Spastic weakness - most commonly in legs
Myelitis
UMN signs predominate - weakness, spasticity, brisk reflexes
What cerebellar signs are seen in MS?
Ataxia - falls
Intention tremor
Scanning speech ie monotonous
Nystagmus
What sexual/GU symptoms are seen?
Erectile dysfunction
Anorgasmia
Urine retention
Incontinence
Constipation
Swallowing disorders
Other than optic neuritis, what other eye pathology is seen?
Diplopia - eyes not moving in a coordinated way
Hemianopia
Pupil defects (RAPD)
Bilateral internuclear opthalmoplegia - a condition affecting movement of eyes that is characteristic of MS. When covering one eye unilateral movements will be normal. But when together, the adducting eye will not move past midline (may affect one or both eyes). Due to a lesion in the medial longitudinal fasciculus - a heavily myelinated tract that connects optic brainstem nuclei on either side of brainstem (so conjugate movement but not unilateral movement is affected)
Is cognitive decline seen in MS?
Yes
Also visuospatial decline
How is MS diagnosed?
Clinically based on McDonald criteria and after alternative diagnosis excluded.
Early diagnosis reduces relapse rates and disability
What investigations should be done?
MRI of brain and spinal cord - demonstrate demyelination plaques. This is sensitive but not specific.
- helps to rule out other causes e.g cord compression
Immunoelectrophoresis of CSF - shows oligoclonal bands of IgG (suggests CNS inflammation)
Visual Evoked Potentials - can detect lesions in visual pathway - patient has EEG probes on skull to measure brain response to visual stimuli (if response delayed, suggests lesion)
- can also do auditory and somatosensory evoked potentials