Multiple Sclerosis (8.7)

Question 1

Outline the clinical features of MS

Answer 1

Progressive inflammatory demyelinating disease of the CNS causing the development of neurological symptoms. Clinically defined by 2 episodes of neurological dysfunction, separated in time and space.

Classic presentation: Female 20-40 y/o, with temporary visual (1 eye) or sensory loss (peculiar sensory phenomena)

• Hemi-sensory and motor disturbance
• Visual disturbance: Optic neuritis (decreased visual acuitiy and colour vision)
• Speech and balance disturbance (cerebellum)
• Diplopia, vertigo, dyspahgia, ataxia, nystagmus, internuclear ophthalmoplegia (brain stem)

ALSO:

Transverse myelitis - Inflammation of the spinal cord (typically cervical). Symptoms include weakness, sensory disturbance and bladder/bowel/sexual dysfunction. If multiple episodes are experienced then can be defined as MS.

Clinically isolated syndrome (CIS): Suggestive of MS

Question 2

Outline the diagnosis of MS

Answer 2

Transient visual, cerebellar, sensory, motor or gait disturbance for 48 hours in the absence of fever or intercurrent illness

Relapsing-remitting MS:

• Diagnosis may be made on clinical grounds alone or via integration of imaging and clinical findings
• Must be evidence of 2 or more ‘attacks’ and the attacks must be occurred at different times (oligoclonal bands)

Secondary progressive MS:

-

Primary progressive MS:

• Insidious neurological progression in the absence of relapse for 6-12 months
• Difficult to diagnose

Question 3

Describe the pathogenesis of MS

Answer 3

Autoimmune inflammatory demyelinating condition in which autoimmune T cells cross the BBB and damage the myelin covering of neurones. Inflammatory cytokines activate immune cells whilst also causing direct neurotoxicity. Plasma cells are also activated, allowing for the production of anti-myelin Igs - which opsonise myelin. Plaques form within the CNS.

In relapsing-remitting MS oligodendrocytes have the ability to perform demyelination, allowing for remission.

In secondary and primary progressive there is no remyelination and axonal loss/damage is seen, causing neurones to become sparse.

Question 4

Outline the treatments available for MS

Answer 4

1. Disease-modifying treatments: Modulates the activity of the immune system to decrease the occurrence of demyelination
2. Steroids: Reduce inflammation
3. Treatment of symptoms: For PP and SP
   
   • Spasticity: Physiotherapy; FES; baclofen; botulinum toxin
   • Neuropathic pain: Gabapentin; amytriptyline; pregabalin
   • Neurogenic bladder: Parasympathetic supply still active - leads to detrusor muscle overactivity

Question 5

Outline the aetiology of MS

Answer 5

☆MULTIFACTORIAL☆

Viral: Inflammatory demyelination e.g. EBV

Genetic factors: HLA alleles

Environmental factors: Geographical variation linked to Vitamin D deficiency