Miscellaneous Neurological Disorders Flashcards
What is the most common acquired disease of myelin?
multiple sclerosis
What is the main job of the myelin sheath?
The main job of a myelin layer (or sheath) is to increase the speed at which impulses propagate along the myelinated fiber.
- What is the problem in the pathophysiology of MS?
- What does this result in?
2
- Body mistakenly directs antibodies and white blood cells against proteins in the myelin sheath.
- Results in inflammation and injury to the sheath and ultimately to the nerves that it surrounds.
-The result may be multiple areas of scarring (sclerosis).
- These areas of demyelination are found scattered in the? 3
- Eventually, damage can slow or block the nerve signals that control what? 4
- Initiating cause is what?
- white matter of the brain,
- spinal cord and
- optic nerve (off up to disc ratio/afferent pupillary defect)
- muscle coordination,
- strength,
- sensation and
- vision.
- unknown!!
Pathogenesis of MS involves what?
2
- autoimmune-mediated inflammatory demyelination
2. axonal injury
Pathogenesis involves autoimmune-mediated inflammatory demyelination and axonal injury: Specifically what happens at the microscopic level?
3
- Peri-vascular infiltrates by lymphocytes and monocytes
- MHC (major histocompatibility complex) antigen expression.
- HLA-DR2 – increases risk
What is MS characterized by?
2 (early and late)
Is characterized by
- relapses, followed in most cases by some degrees of recovery.
- Relapsing-remitting
Eventually progresses to continual disease
MS: Areas commonly affected (and what they control)?
7
- Optic nerve
- Corticobulbar tracts (speech & swallowing)
- Corticospinal tracts (muscle strength)
- Cerebellar tracts (gait & coordination)
- Spinocerebellar tracts (balance)
- Longitudinal fasciculus (conjugate gaze, EOM’s)
- Posterior cell columns of the spinal cord
- –(position and vibratory sense)
MS occurs in what ages?
Usually occurs between ages 15-50
Geographically what is the risk?
Geographical factors:
More common in countries with temperate climates, including Europe, southern Canada, northern United States, and southeastern Australia. The reason is unknown.
Northern latitude populations have a very high incidence.
No population with a high risk for MS exists between latitudes 40N and 40S.
Potential environmental factors?
1
- Many viruses and bacteria have been suspected of causing MS, most recently the Epstein-Barr virus.
Some studies have suggested that developing infection at a critical period of exposure may lead to conditions conducive to the development of MS a decade or more later.
MS symtpoms?
10
- Weakness, numbness, tingling or unsteadiness in a limb
- –“Lhermitte’s symptom’s” - Unilateral visual impairment
- Fatigue
- Spastic paraparesis (what’s paraparesis??)
- Diplopia
- Disequilibrium
- Muscle weakness
- Sphincter disturbance such as urinary urgency or hesitancy
- Dysarthria
- Mental disturbance
MS signs?
7
- Optic neuritis (can often be the initial episode for a patient who develops MS)
- Opthalmoplegia
- Nystagmus
- Spasticity or hyperreflexia
- Babinski sign
- Absent abdominal reflexes
- Labile or changed mood
MS Younger patients Subacute or acute onset of focal neurologic symptoms and signs reflecting? 5 (signs)5
- Optic nerve
- Pyramidal tracts
- Posterior columns
- Cerebellum
- Central vestibular system
MS
Older patients
Insidiously progressive myelopathy?
(signs) 3
- Spastic leg weakness
- Axial instability
- Bladder impairment