Multiple Sclerosis Flashcards
What is multiple sclerosis?
a chronic and progressive autoimmune condition involving demyelination in the central nervous system
Does MS affect the central or peripheral nervous system?
Central
Is MS more common in men or women?
Women x3
What cells provide myelin to the CNS?
Oligodendrocytes
What cells provide myelin to the PNS?
Schwann cells
Describe the pathophysiology of multiple sclerosis: (2)
1) the immune system attacks the myelinated sheath of CNS myelinated neurons
2) the immune cell infiltration affects electrical signals moving across the neurons
True or false: re-myelination can occur in the early stages of MS
True
What phrase is used to describe the varying lesion patterns of MS?
disseminated in time and space
Give 5 potential causes of MS:
1) genetics
2) Epstein-Barr virus
3) low vitamin D
4) smoking
5) obesity
What is the most common presentation associated with multiple sclerosis?
optic neuritis
What is optic neuritis?
demyelination of the optic nerve, presenting with unilateral reduced vision developing over hours to days
Give 4 clinical findings associated with optic neuritis:
1) central scotoma
2) pain with eye movement
3) impaired colour vision
4) relative afferent pupillary defect
What is a central scotoma?
a large central blind spot
What is a relative afferent pupillary defect?
where the pupil in the affected eye constricts more when shining a light in the contralateral eye than when shining in the affected eye
What drug class is used to treat optic neuritis?
Steroids
Give 5 eye movement abnormalities associated with optic neuritis:
1) diplopia
2) nystagmus
3) oscillopsia
4) internuclear ophthlamoplegia
5) conjugate lateral gaze disorder
Eye movement abnormalities indicate lesions in which nerves? (3)
1) oculomotor nerve
2) trochlear nerve
3) abducens nerve
What is oscillopsia?
the visual sensation of the environment moving and being unable to create a stable image
How does internuclear ophthalmoplegia present? (2)
1) impaired adduction in the ipsilateral eye
2) nystagmus
A lesion to which structure causes internuclear ophthalmoplegia?
medial longitudinal fasciculus
Explain why a lesion to the medial longitudinal fasciculus causes eye movement abnormalities:
the medial longitudinal fasciculus connects the cranial nerve nuclei of CN III, IV and VI which allows coordination of eye movement
How does conjugate lateral gaze disorder present?
1) both eyes drift laterally
2) when looking laterally in the direction of the affected eye, the affected eye will not be able to adduct
Conjugate lateral gaze disorder indicates an MS lesion to which nerve?
abducens nerve
Give 8 general neurological symptoms that may be seen in MS:
1) incontinence
2) Horner syndrome
3) facial nerve palsy
4) limb paralysis
5) trigeminal neuralgia
6) numbness
7) paraesthesia
8) Lhermitte’s sign
