MS – TN 2014

A chronic inflammatory dz of CNS characterized by relapsing remitting, or progressive neurologic symptoms due to inflammation, demyelination and axonal degeneration

Clinical features

1. Relapsing remitting (RRMS) 85% (0.4-0.6 relapses /yr, highest in the 1st year) – most go on to become SPMS
   • Relapse: acute/subacute onset of clinical dysfunction that peaks from days(>24hr) to weeks, followed by remission with variable symptom resolution
2. Primary progressive (PPMS) 10%
   • poor prognosis, higer rates of disability, poor response to therapy
3. Progressive relapsing (PRMS) 5%
4. Secondary progressive (SPMS)
5. Onset: 17-35; 3F:1M

Etiology

• Genetic – polygenetic
• Environmental:
  • More common in regions with less sun exposure & lower stores of Vit D
  • Linked to certain viruses (EBV)

Dx: Revised McDonald criteria

1. Dissemination in time: ≥ 2 attacks, new gadolinium enhancing lesion 3 mo later, or new T2 lesions >1 mo after first attack
2. Dissemination in space: clinical evidence of ≥ 2 lesions

Clinical features: Most symptoms in MS are due to cord, brainstem, and optic nerve lesions

• Numbness, visual disturbance (optic neuritis), diplopia (INO), weakness, spasticity, impaired gait, vertigo, bladder dysfunction
• Lhermitte’s sign: flexion of neck causes electric shock sensation down back into limbs (cervical cord lesion)
• Uhthoff’s phenomenon: worsening of symptoms (classically optic neuritis) in heat
• SPMS: weakness of legs in pyramidal distribution paired with cerebellar findings of arms (intention tremor)
• NOT commonly found in MS: visual field defects, aphasia, apraxia, progressive hemiparesis
• EDSS – Expanded Disability Status Scale – measure disability progression (0-10)

Ix

• MRI: dymyelinating plaques – hyperdense lesions on T2
• CSF: oligoclonal bands in 90%, increased IgG [ ]
• Evoked potential (visual / auditory / somatosensory): delayed but wel-preserved wave forms

Tx

1. Acute Tx: methylprednisolone 1g IV daily x 3-7 days – plasma exchange if poor response
2. Disease modifying therapy (DMT)
   • Goals: ↓ relapse rate, progression of disability, slow accumulation of MRI lesions
   • 1st line: interferon-B (early Tx may delay potential second attack)
   • reduce RRMS rate of relapse by ~30%
   • No proven efficacy in PPMS / SPMS
3. Education & counseling: MS society, support groups, psychosocial issues
4. Symptomatic Tx
   • Spasticity: baclofen / BZD / botox
   • Bladder dysfunction: oxybutynin
   • Pain: TCA, gabapentin, carbamazepine
   • Fatigue: amantidine, methylphenidate
   • Depression: SSRI / Li
   • Constipation: high fibre, stool softner, laxatives
   • Sexual dysfunction: sildenafil

Good Prognostic indicators:

• female, young
• RRMS, presenting with optic neuritis
• low burden of dz on initial MRI
• low rate of relapse early in dz

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References:

• TN 2014