Multiple Sclerosis

Question 1

What is multiple sclerosis?

Answer 1

• Idiopathic inflammatory demyelinating disease of the CNS
• To be classified as MS lesions are disseminated in time and space
• Acute episodes of inflammation are associated with focal neurological deficits
• Demyelination results in loss of neurological function (i.e. weak leg, visual loss, urinary incontinence)
• Deficits develop gradually, last for more than 24hrs and may gradually improve over days to weeks
• Later in untreated disease patients may become progressively more disabled

Question 2

What syndromes can develop into MS?

Answer 2

• Optic neuritis (painful visual loss, reduced colour vision - red desaturation, pain on eye movement and enlarged blind spot)
• Clinically isolated syndromes (single episode of neurological disability due to focal CNS inflammation)
• Transverse myelitis (inflammatin of the spinal cord, weakness, sensory loss, incontinence)
• Radiologically isolated syndromes (found on MRI)

Question 3

What are the symptoms of MS? (bold most common)

Answer 3

• Central (fatigue, cognitive impairment, depression, unstable mood)
• Visual (nystagmus, optic neuritis, diplopia - 6th nerve palsy)
• Speech (dysarthria)
• Throat (dysphagia)
• MSK (weakness, spasms, ataxia - sensory or cerebellar)
• Sensation (pain, hypoesthesias, parasthesias)
• Bowel (incontinence, diarrhoea or constipation)
• Urinary (incontinence, frequency or retention)

Question 4

How is MS diagnosed?

Answer 4

• Evidence of 2 or more episodes of demyelination disseminated in space and time
• MRI (with gadolinium contrast, evidence of demyelination in 2 regions)
• LP (CSG oligoclonal bands with matched blood sample)
• Bloods (B12/folate, serum ACE, lyme serology, ESR/CRP, ANA/ANCA/Rheumatoid factor, aquaporin-4 antibodies)
• Visual evoked potentials (slower conduction if optic neuritis in the past)
• For optic neuritis:
  
  • Central scotoma (enlarged blind spot)
  • Pain on eye movement
  • Impaired colour vision
  • RAPD

Question 5

What are the different subtypes of MS?

Answer 5

• Clinically isolated syndrome (single episode - cannot be diagnosed as MS)
• Relapsing remitting (attacks followed by remission)
• Secondary progressive (intial attacks and remission then periods with no remission)
• Primary progressive (steady increase in disability)
• Progressive relapsing (steady decline since onset with superimposed attacks)
• Benign MS (fit diagnostic criteria but no disability)

NB - Can be active, not active, worsening, not worsening, progressive and not progressive.

Question 6

How is MS relapse treated?

Answer 6

• Managed by MDT
• Steroids spped up recovery from attacks (methylprednisolone IV)
• Disease modifying drugs can be given (alemtuzumab, natalizumab, fingolimod, dimethyl fumarate)
• Symptomatic treatments
  
  • Exercise for muscle strength
  • Medication for neurpathic pain (i.e. amitriptyline)
  • Antidepressants for depression
  • Anticholinergic medications for urge incontinence
  • Medication for spasticity (i.e. baclofen, gabapentin)

Question 7

Pathophysiology of MS

Answer 7

• Myelin covers axons in the CNS and helps electrical impulse move faster along the axon
• Myelin provided by cells called Schwann cells (PNS) and oligodendrocytes (CNS)
• MS only affects CNS
• Inflamnmation around myelin and infiltration of immune cells damages the myelin

Question 8

Causes of MS

Answer 8

• Cause unclear but influenced by:
  
  • Multiple genes
  • EBV
  • Low vitamin D
  • Smoking
  • Obesity