Misc neuro disorders Flashcards
1
Q
rundown of MS?
A
- most common acquired disease of myelin. Mainmjob of myelin is to increase speed at which impulses propagate along myelinated fiber
- body mistakenly directs Abs and WBCs (lymphocytes, macrophages, proteolytic enzymes) against proteins in myelin sheath
- results in inflammation and injury to sheath and ultimately to nerves that it surrounds
- the result may be multpile areas of scarring (sclerosis)
- initiating cause is unkown!
2
Q
Where are the areas of demylenation of MS found?
A
- found scattered in white matter of brain, spinal cord and optic nerve
- eventually damage can slow or block nerve signals that control muscle coordination, strength, sensation and vision
3
Q
Pathogenesis of MS? Characterized by?
A
- involves autoimmune mediated inflammatory demyelination and axonal injury:
- peri-vascular infiltrates by lymphocytes and monocytes
- MHC antigen expression
- HLA-DR2 - increases risk
- characterized by relaspses, followed in most cases by some degrees of recovery: relapsing-remitting
- eventually progresses to continual disease
4
Q
Areas commonly affected by MS?
A
- optic nerve
- corticobulbar tracts (speech and swallowing)
- corticospinal tracts (muscle strength)
- cerebellar tracts (gait and coordination)
- spinocerebellar tracts (balance)
- longitudinal fasciculus (conjugate gaze, EOMs)
- posterior cell columns of spinal cord (position and vibratory sense)
5
Q
MS most common in?
A
- in women
- usually occurs b/t ages 15-50
- annual incidence rate is increasing
- genetic link established
- geographical factors: more common in countries with temperate climates, including Europe, southern canada, N US, and SE australia, reason unknown
6
Q
Enviro factors in MS?
A
- many viruses and bacteria have been suspected of causing MS, most recently the EBV
- some studies have suggested that developing infection at critical period of exposure may lead to conditions conducive to development of MS a decade or more later
7
Q
Sxs of MS?
A
- weakness, numbness, tingling, or unsteadiness in limb - “Lhermitte’s sxs)
- unilateral visual impairment
- fatigue
- spastic paraparesis
- diplopia
- disequilibrium
- muscle weakness
- sphincter disturbance such as urinary urgency or hesitancy
- dysarthria
- mental disturbance
8
Q
Signs of MS?
A
- optic neuritis (can often be initial episode for pt who develops MS)
- opthalmoplegia
- nystagmus
- spasticity or hyperreflexia
- babinski sign
- absent abdominal reflexes
- labile or changed mood
9
Q
Diff in MS in younger and older pts?
A
- younger: subacute or acute onset of focal neuro sxs and signs reflecting:
optic nerve, pyramidal tracts, posterior columns, cerebellum, central vestibular system (vertigo) - older: insidiously progressive myelopathy:
spastic leg weakness, axial instability, bladder impairment
10
Q
MS pattern of disease?
A
- majority of pts have resolution of initial sxs then fall into following pattern of relapsing-remitting disease - this is seen in majority of pts, interval of months to year after initial episode b/f new sxs develop or original ones reoccur
- infection, fever, and trauma precipitate or trigger exacerbations
- relapsse are more likely during 2-3 months following pregnancy (immune system is building back up)
- as disease progresses increasing disability with weakness, spasticity, ataxia, impaired vision, and urinary incontinence
11
Q
diff forms of MS?
A
- secondary progressive: clinical course changes so that a steady deterioration occurs, unrelated to acute relapses
- primary progressive disease: less common, steady progression from onset, disability develops at relatively early stage
- benign: no disability, return to normal in b/t attacks
- relapsoing-remitting: never new disaibilty b/t attacks, but after attack - baseline is worse
12
Q
How do you dx MS?
A
- complete hx and physical
- signs and sxs complaints
- neuro exam
- neuroimaging is an adjunct to clinical info:
MRI of head or cervical cord (85% clinically definite in MS pts, IV gadolinium enhances acute lesions) - clinical dx: 2 or more exacerbations greater than 2 months apart, last 24 hrs each but recover
- CT scans are not helpful and not sensitive
- if neg MRI ans suspicious - do LP - can have protein elevations, lymphocytosis, elevated IgG, myelin abs, oligoclonal bands
but tests can be altered in variety of inflamm neuro disorders and aren’t specific for MS
13
Q
Lesions of MS are? Where do they commonly occur?
A
- multifocal
- hyperintense (light up)
- occur predominantly in:
peri-ventricular white matter
corpus callosum
cerebellum
cerebellar peduncles
brainstem
spinal cord
14
Q
Definitive dx of MS?
A
- requires intermittent or progressive CNS sxs supported by evidence of 2 or more CNS white matter lesions occurring in an appropriately aged pt
- clinical picture must indicate involvement from different part of CNS at diff times
15
Q
Probable dx of MS?
A
- multifocal white matter disease but only one clinical attack, or with hx of at least 2 clinical attacks but signs of only one lesion
- preferably a neuro consult when MS suspected or confirmed
- kurtzke expanded disability status scale used to measure disease progression (0-10)
16
Q
Tx basis for MS? Tx for minimally affected pts?
A
- directed at modifying course and managing primary sxs
- minimally affected pts:
reqr no specific tx
encourage to maintain healthy lifestyle:
avoid excessive fatigue, emotional stress, viral infections, extremes of temperatures - physical therapy
17
Q
Pharm tx categories?
A
- tx acute sxs
- modify course of disease
- interrupt progressive disease
- tx continuing sxs
18
Q
What is mainstay of tx for acute exacerbations? How does it help?
A
- corticosteroids
- reduce inflammation
- improve nerve conduction
- long term admin doesn’t alter coruse of disease and can have harmful side effects
19
Q
What drugs are used to modify course of MS?
A
immune modifiers:
interferon 1a
interferon 1b
glatiramer acetate
20
Q
Drugs used for progressive MS?
A
- immunosuppressants: methotrexate (rheumatrex) cyclophosphamide (cytoxan) mitoxantrone (novantrone) azathiprine (imuran)*
21
Q
Tysabri (natalzumab) tx?
A
- lab produced monoclonal ab
- designed to hamper movemetn of potentially damaging immune cells from bloodstream across BBB into brain and spinal cord
- approved in 2006 as monotherapy for tx of relapsing forms of MS
- but it increases risk of progressive multifocal leukocephalopathy (PML - further damages myelin) - only recommended for those who have inadequate response to or can’t tolerate alt MS therapy