Multiple Sclerosis Notes

Multiple Sclerosis

Demyelination of the CNS causing relapsing and remitting neurological disturbance

Epidemiology

• Commoner in temperate areas

• Lifetime UK risk 1:1000

• F>M 2:1

• Mean age of onset is 30 years

Aetiology/Pathogenesis

• Genetic susceptibility + environmental trigger

• Myelin is lost from the brain + spinal cord (throughout the CNS, but not peripheral nerves)

• Leads initially to a relapsing (demyelination) and remitting (remyelination) neurological disturbance but ultimately in all but a few patients to a permanent and progressive disability as a result of loss of axons

Clinical features

• Presentation is usually monosymptomatic

  • Unilateral optic neuritis

    • Pain on eye movement and rapid deterioration in central vision

  • Numbness and tingling in limbs

  • Leg weakness

  • Brainstem/cerebellar symptoms e.g diplopia/ataxia

• Symptoms may worsen with heat or exercise

• Possible features

  • Optic neuritis:

    • Acute phase – central visual field defect, worse on eye movement, often normal fundoscopy, usually recovers in 10-20 days

    • Chronic phase – fundoscopy shows optic atrophy (pale disc), visual loss often minor (i.e reduced colour vision)

  • Motor weakness

    • Due to pyramidal tract damage (UMN)

    • Weakness – arm extension/leg flexion

    • Spasticity – increased tone, “claspknife” pattern

    • Increased reflexes +/- clonus +/- upgoing plantars

  • Sensory loss

    • Altered sensation

    • Can occur anywhere

    • If isolated symptom, differential = hyperventilation, peripheral neuropathy

  • Cerebellar signs often prominent e.g ataxia, intention tremor, scanning speech

  • Brainstem involvement

    • Internuclear opthalmoplegia casing a dysconjugate eye gaze

    • Trigeminal neuralgia-like syndrome

    • Recurrent facial nerve palsy

  • Spinal cord damage

    • Gradual onset spastic para-or tetraparesis

    • Acute transverse myelitis – leads to flaccid paralysis in acute phase, spasticity in chronic phase

    • Dorsal column damage – abnormal gaite ‘sensory ataxia’ due to loss of proprioception

  • Intellectual loss in longstanding MS – dementia

  • Fatigue, reduced cognition, reduced memory

  • Depression, mania

Patterns of disease

• Relapsing and remitting

  • Initially the patient presents with episodes of monophasic neurological disturbance

  • Returns to normal function between these episodes

  • Thereafter patient may not return to normality, so there is a background of progressive dysfunction with superimposed relapses (termed secondary progressive MS)

• Relapsing progressive

  • Progressive course with superimposed relapses but no recovery between episodes

• ...

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