MS Flashcards
what is the common group of people affected by MS?
Female: male 3:1
30s and 40s
what is MS?
autoimmune inflammatory demyelinating disorder the central nervous system
what is the structure of MS lesions?
lesions that are a greyish colour, 1mm to several cm in size, present in white matter of the brain and spinal cord
where do MS lesions arise?
adjacent to lateral ventricles, corpus callosum, optic nerves, chiasm, brainstem ascending and descending fibre tracts, cerebellum, spinal cord
lesions lie in close relationship to veins – perivenous distribution
what are the 2 overlapping phases of MS?
Inflammatory
Degenerative
what is the underlying mechanism of MS?
plaques resulting in demyelination, loss of oligodendrocytes and astrogliosis
what are the 3 different types of lesions in MS?
Recent Lesions
Old Lesions
Shadow Plaques
what are the cause of MS?
- Genetics – HLA region
- environmental factors – toxins, viral exposure (EBV), sunlight (VIT D)
- relapses triggered post-natal
- immunodeficiency
- smoking
what do recent MS lesions look like?
Are yellow/brown in colour with an ill-defined edge that blends into white matter
what do old MS lesions look like?
well-demarcated grey/brown lesions in white matter, classically situated around lateral ventricles
what are the microscopic features of recent MS lesions?
myelin destruction, relative axon sparing, perivenous infiltration with mononuclear cells and lymphocytes. interstitial oedema. Breakdown of the BBB which causes myelin destruction. perivascular inflammatory cells, microglia, ongoing demyelination.
what are the microscopic features of old lesions?
relatively acellular, bare axons are surrounded by astrocytes. Gliosis, little remaining myelinated axons, oligodendrocytes and axons reduced in number.
what are the microscopic features of shadow plaques in MS?
may reflect a degree of remyelination, demonstrate thinned out myelin sheaths at the edge of lesions, results in a less well-defined lesion
what process occurs in the inflammatory phase of MS?
T cells enter the CNS via receptors on endothelial cells. Results in a breach in the BBB, causing upregulation of endothelial adhesion molecules and inflammatory cells. T cells produce inflammatory cytokines that cause direct toxicity and attract macrophages that contribute to demyelination.
what is the degenerative process in MS?
Demyelination disrupts axonal support and leads to destabilisation of axonal membrane potentials, which causes distal and retrograde degeneration over time. Inflammatory cells, antibodies, and complement also contribute to axonal injury.
what are the clinical features of MS?
• visual disturbance in one eye • peculiar sensory phenomena • vague symptoms • Pyramidal Dysfunction • Sensory Symptoms • Cerebellar dysfunction • Brain Stem Dysfunction • Internuclear Ophthalmoplegia • Urinary Tract Dysfunction
what are the clinical features associated with visual disturbance in MS?
optic neuritis – painful visual loss, 1-2 weeks, most improve, RAPD
ALSO:
o pale optic disc or non-correctable visual loss
o incorrect responses to Ishihara colour blindness test plates
o abnormal eye movements
what are the vague symptoms associated with MS?
o fatigue
o headache
o depression
o ache in limbs - cramping
what are the clinical features associated with pyramidal dysfunction n MS?
o spasticity/increased muscle tone
o Weakness
o Extensors of upper limbs
o flexors of lower limbs
what are the sensory symptoms associated with MS?
o pain o paraesthesia o dorsal column loss – proprioception & vibration o numbness o trigeminal neuralgia
what are the symptoms of cerebellar dysfunction associated with MS?
o ataxia o intention tremor o nystagmus o past pointing o pendular reflexes o dysdiadokinesis o dysarthria o imbalance/ incoordination o foot dragging
what are the symptoms of brain stem dysfunction in MS?
o diplopia – R VI palsy
o Facial weakness – R VII palsy
what are the symptoms of Internuclear Ophthalmoplegia in MS?
o Medial longitudinal fasciculus o Distortion of binocular vision o Failure of adduction- diplopia o Nystagmus in abducting eye o Lag
what are the symptoms of urinary tract dysfunction associated with MS?
o frequency o nocturia o urgency o urge incontinence o retention
