MS and other demyelinating disorders Flashcards
MS is presumed to an an _______ disorder causing _____ (what is it doing to the NS) of the _____ nervous system.
Affects at least ____ americans
Generally affects: M or F? ethnicities? age? location?
Increasing risk factors?
MS is presumed to an an AUTOIMMUNE disorder causing DEMYELINATION of the CENTRAL nervous system.
Affects at least 400 K americans
Generally affects: YOUNGER FEMALES (20-50s), of NORTHERN EUROPEAN descent
Risk: INC w/increasing distance from the equator (low Vitamin D?), some genetic contribution but NOT a genetic disease (HLA markers, and SNPs increase risk); Viral exposures (EBV! esp pediatric population, canine distemper virus), tobacco exposure
Charcot’s Triad of MS consists of:
Nystagmus, intention tremor, scanning speech
“Pathogenesis” of MS
______ cells, possible traveling from the cranial vault, present some signal and activate primed autoreactive _____-cells residing @_____.
Activated _____ cells leave the lymph nodes and enter the peripheral blood stream looking for that target -( preasumbaly found in the CNS)
These cells attach to, breakdown and cross the ________.
How?
“Pathogenesis” of MS
APC cells, possible traveling from the cranial vault, present some signal and activate primed autoreactive T-cells residing @ LYMPH NODES.
Activated T-cells leave the lymph nodes and enter the peripheral blood stream looking for that target -( preasumbaly found in the CNS)
These cells attach to, breakdown and cross the BLOOD-BRAIN-BARRIER
By: releasing interleukins that cause inflammatory respones and disrupt the BBB; secrete pro-inflammatory cytokines –> myelin destruction and neuronal death
(cell may become “chronically” activate within the CNS over time leading to progressive neurodegeneration)
Can the nerve restore the demyelination?
The disease is characterized by type of pathogenesis?
What is the frequency of relapse?
Over time, the nerve can myelinate but not as well, and chronic demyelination of the axon may not be reversible. Conduction is semi-resotred by increasing the sodium channels in the areas of demyelination
The disease is characterized by clinical relapses = new neurological signs/symptoms lasting > 24 hours, due to CNS demyelination followed by remission (complete/partial improvement of symptoms)
The frequency of relapse varies, but on average one every 1-2 years for the first 5-10 years of illness after disease onset; over time pt develope progressive symptoms withouth clear clinical relapse/new lesions
What syndromes are highly suggestive of MS?
Optic neuritis
Brainstem syndromes- internuclear opthalmoplegia, oculomotor dysfunction, ataxia, trigemianal neuralgia, facial nerve palsy, CST/upper motor neuron involvement
Spinal Cord Syndrome
Romberg sign
silent symptoms of MS: fatigue, bladder dysfunction, sexual dysfunction, spasticity, pain, cognitive impairment, bowel dysfunction
Ocular Neuritis-
What symptoms is this associated with?
What clinical test/responds (2) are suggestive?
–fuzzy, absent/impaired vision –
Decreased mononuclear vision
Pain with eye movement
Decreased red/green color
Swollen/blurred disc
Associations:
AFFERENT PUPILLARY DEFECT, APD = MARCUS-GUNN PUPIL
UHTHOFF PHENOMEON (heat intolerance/hot bath test- myelin and axon is temp dependent so if they overheat they won’t work as well and APD will be more prevalent)
What is this suggestive of?
Brainstem syndrome associated with MS
MS likes to be around the pineal surface
Classic MS lesion, bring white spot, right in the back, against the pineal (see image) - MS lesions tend to hug the periphery of the brainstem vs vascular lesions (stroke) tend to be internal
What is this suggestive of?
Internuclear opthalmoplegia
Pt with MS, tend to have white matter lesions in the back of the brain near the 6th nuclei.
MLF is a long axon thus MS likes to attack it
**intranuclear opthalmoplegia is almost pathoneumonic for MS**
What is the new criteral for MS diagnosis
- diagnosis rests on the objective demonstration of CNS white matter lesions - based on CLINICAL and RADIOGRAPHIC grounds, that are disseminated in time and space for which there is no better alternative diagnosisi*
- There is NO single test that confirms MS*
What does it mean by dissemination in space?
What does it mean by dissemination in time?
Dissemination in space: at least ONE T2 LESION that is characteristic in appearance for MS, in at least TWO out of FOUR locations characteristic for MS
Disseminatino in time: a NEW T2 lesion and/or GdE lesion on follow up MRI irrespective of the timing of the baseline MRI; can diagnose off of a single MRI
What are the four locations considered characteristic for MS?
Juxtacortical, periventricular, infratentorial, spinal cord
What do these images represent?
- left to right*
- Juxtacortical, periventricular, infratentorial, GdE lesion*
What are the typical lesions of MS in a MRI?
Lesions > 3mm
Corpus callosum lesions
Optic radiation lesions
Braintstem lesions abutting the 4th ventricl or aqueduct
Incomplete/partial enhancement
T1 “black holes”
What does the image represent?
Dawson’s fingers
Perpendicular oriented periventricular lesions
sagittal flare
Virtually pathognomonic for MS
What is characterisitic of spinal cord lesions associated with MS?
typically small <1-2 vertebral levels
located in the cord peripheral, especially the dorsal colums
Lesion begin at the pial surface, very few other neurological disease (esp stroke) cause discrete spinal cord lesions and brain lesions
*Brain + spain cord lesions –> think: MS*
