Multiple Sclerosis
Study guide:
Definition: A T-cell mediated autoimmune demyelinating disease affecting the CNS
myelin and oligodendrocytes.
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Recurrent episodes of neurological dysfunctions separated in space and time.
Epidemiology:
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Most common type CNS diseases in young adults (20-30 Y/O).
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More common in women (M: F ratio is 1:2).
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High prevalence in temperate climate and in North Europe (away from the equator).
Risk factors and Causes:

Pathophysiology:
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Th1 and Th17 will react against self-antigen myelin ➔Type IV hypersensitivity reaction.
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Th1 ➔ secretes γ-IFN ➔ TNF-α.
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Th17 ➔ release cytokines to recruit neutrophils and monocytes.
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Activated leukocytes and TNF-α are responsible for causing the demyelination (mainly in the periventricular area).
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Other studies reveal the role of auto-reactive B-cells in the demyelination process (type II hypersensitivity reaction).
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After the demyelination, gliosis takes place, causing shrinkage in the grey matter.
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Inflammatory mediators released during an attack (NO particularly) initiate axonal damage ➔ progressive and persistent disability.
Types:
Clinical Presentation:
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Characteristic presentation:
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Optic Neuritis:
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Inflammation of the optic nerves and its most common cause is MS.
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Brain demyelination symptoms:
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Bilateral intranuclear ophthalmoplagia, which is demyelination of the medial longitudinal fasciculus (Hallmark of MS).
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Vertigo and scanning speech (alcohol intoxication).
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Spinal cord lesion:
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Asymmetrical paraparesis.
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Difficulty in walking.
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Unilateral loss of sensation.
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Others:
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Autonomic dysfunction: bowel, bladder, and sexual dysfunction.
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Mentation is intact (dementia is rare).
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Triggers of the acute attack: infections, physical and emotional stress, and metabolic upset.
Diagnosis:
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McDonald’s Criteria
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Lesions should be disseminated in time and space, either by history or by MRI and CSF.
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Clinically Definite MS:
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2 episodes of symptoms.
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2 white matter lesions (Clinically or on imaging).
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MRI
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Lesions in periventricular areas, corpus callosum and juxtacortical white matter in the brain.
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Initial and most accurate test.
CSF
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Increased lymphocytes.
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Increased immunoglobulins
with oligoclonal IgG bands. -
Myelin basic protein.
Management:
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Acute exacerbation treatment:
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I.V methylprednisolone (corticosteroids).
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Disease-modifying treatment:
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Beta-interferon and glatiramer acetate (Immunomodulatory therapy).
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Symptomatic supportive treatment:
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Baclofen/Dantrolene ➔ muscle spasticity
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Carbamazepine/Gabapentin ➔ neuropathic pain
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Treat depression if present.
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Prognosis:
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Good prognostic factors:
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Optic neuritis (pure sensory).
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RRMS type.
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Complete recovery from the first attack.
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Only 5% will die within 5 years from the disease onset.
References:
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Agabegi, Steven S, Elizabeth D Agabegi, and Adam C Ring. Step-Up To Medicine. Philadelphia: Wolters Kluwer/Lippincott Williams & Wilkins, 2013. Print.
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Kumar, Parveen J, and Michael L Clark. Kumar & Clark's Clinical Medicine. Print.
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Hauser, Stephen, and Scott Josephson. Harrison's Neurology In Clinical Medicine. 3rd ed. McGraw Hill. Print.
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Yogarajah, Mahinda. Neurology. Edinburgh: Mosby/Elsevier, 2014. Print.
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Sattar, Husain A. Fundamentals Of Pathology. Chicago: Pathoma.com, 2011. Print.
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Le, Tao, Vikas Bhushan, and Herman Singh Bagga. First Aid For The USMLE Step 2 CK. New York: McGraw-Hill Medical, 2010. Print.
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Le, Tao et al. First Aid For The® USMLE. Print.
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(MS), Multiple. 'Multiple Sclerosis (MS) - Neurologic Disorders'. Merck Manuals Professional Edition. N.p., 2015. Web. 24 Sept. 2015.
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Goljan, Edward F. Rapid Review Pathology. Philadelphia, PA: Saunders/Elsevier, 2014. Print.
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Walker, Brian R et al. Davidson's Principles And Practice Of Medicine. Print.
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Emedicine.medscape.com,. 'Brain Imaging In Multiple Sclerosis: Overview, Computed Tomography, Magnetic Resonance Imaging'. N.p., 2015. Web. 24 Sept. 2015. (Figure 1).
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
