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Multiple Sclerosis

Study guide:

Definition: A T-cell mediated autoimmune demyelinating disease affecting the CNS

myelin and oligodendrocytes.

  • Recurrent episodes of neurological dysfunctions separated in space and time.


Epidemiology:

  • Most common type CNS diseases in young adults (20-30 Y/O).

  • More common in women (M: F ratio is 1:2).

  • High prevalence in temperate climate and in North Europe (away from the equator).


​​​Risk factors and Causes:

Pathophysiology:

  • Th1 and Th17 will react against self-antigen myelin ➔Type IV hypersensitivity reaction.

    • Th1 ➔ secretes γ-IFN ➔ TNF-α.

    • Th17 ➔ release cytokines to recruit neutrophils and monocytes.

  • Activated leukocytes and TNF-α are responsible for causing the demyelination (mainly in the periventricular area).

  • Other studies reveal the role of auto-reactive B-cells in the demyelination process (type II hypersensitivity reaction).

  • After the demyelination, gliosis takes place, causing shrinkage in the grey matter.

  • Inflammatory mediators released during an attack (NO particularly) initiate axonal damage ➔ progressive and persistent disability.  

 

Types:

Clinical Presentation:

  • Characteristic presentation:

    • Optic Neuritis:

      • Inflammation of the optic nerves and its most common cause is MS.

    • Brain demyelination symptoms:

      • Bilateral intranuclear ophthalmoplagia, which is demyelination of the medial longitudinal fasciculus (Hallmark of MS).

      • Vertigo and scanning speech (alcohol intoxication).

    • Spinal cord lesion:

      • Asymmetrical paraparesis.

      • Difficulty in walking.

      • Unilateral loss of sensation.

  • Others:

    • Autonomic dysfunction: bowel, bladder, and sexual dysfunction.

    • Mentation is intact (dementia is rare).

Triggers of the  acute attack: infections, physical and emotional stress, and metabolic upset.

Diagnosis:

  • McDonald’s Criteria

    • Lesions should be disseminated in time and space, either by history or by MRI and CSF. 

  • ​Clinically Definite MS:

    • 2 episodes of symptoms.

    • 2 white matter lesions (Clinically or on imaging).

MRI

  • Lesions in periventricular areas, corpus callosum and juxtacortical white matter in the brain.

  • Initial and most accurate test.

CSF

  • Increased lymphocytes.

  • Increased immunoglobulins 
    with oligoclonal IgG bands.

  • Myelin basic protein.

Management:

  • Acute exacerbation treatment:

    • I.V methylprednisolone (corticosteroids).

  • Disease-modifying treatment:

    • Beta-interferon and glatiramer acetate (Immunomodulatory therapy).

  • Symptomatic supportive treatment:

    • Baclofen/Dantrolene ➔ muscle spasticity

    • Carbamazepine/Gabapentin ➔ neuropathic pain

    • Treat depression if present.

 

Prognosis:

  • Good prognostic factors:

    1. Optic neuritis (pure sensory).

    2. RRMS type.

    3. Complete recovery from the first attack.

  • Only 5% will die within 5 years from the disease onset.

​

References:

  • Agabegi, Steven S, Elizabeth D Agabegi, and Adam C Ring. Step-Up To Medicine. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins, 2013. Print.

  • Kumar, Parveen J, and Michael L Clark. Kumar & Clark's Clinical Medicine. Print.

  • Hauser, Stephen, and Scott Josephson. Harrison's Neurology In Clinical Medicine. 3rd ed. McGraw Hill. Print.

  • Yogarajah, Mahinda. Neurology. Edinburgh: Mosby/Elsevier, 2014. Print.

  • Sattar, Husain A. Fundamentals Of Pathology. Chicago: Pathoma.com, 2011. Print.

  • Le, Tao, Vikas Bhushan, and Herman Singh Bagga. First Aid For The USMLE Step 2 CK. New York: McGraw-Hill Medical, 2010. Print.

  • Le, Tao et al. First Aid For The® USMLE. Print.

  • (MS), Multiple. 'Multiple Sclerosis (MS) - Neurologic Disorders'. Merck Manuals Professional Edition. N.p., 2015. Web. 24 Sept. 2015.

  • Goljan, Edward F. Rapid Review Pathology. Philadelphia, PA: Saunders/Elsevier, 2014. Print.

  • Walker, Brian R et al. Davidson's Principles And Practice Of Medicine. Print.

  • Emedicine.medscape.com,. 'Brain Imaging In Multiple Sclerosis: Overview, Computed Tomography, Magnetic Resonance Imaging'. N.p., 2015. Web. 24 Sept. 2015. (Figure 1).

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First author:             Roaa Amer
Second Authors:      Abdullah AlAsaad           
                                Lama AlLuhaidan 
Reviewers:                Bayan Alzomaili
Format Editor :         Adel Yasky 

Website Publisher:   Bayan Alzomaili

Audio recording:
- ​Read by: Bothainah AlAqeel
- Directed by: Rana Alzahrani
- Audio production: Bayan Alzomaili

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