MS package Flashcards
Myelin is a proteolipid sheath which covers most of the axons which conduct nerve signals. In the CNS, myelin is made by cells called
Oligodendrocytes
This term is used to describe any process which resultsin myelin sheaths being lost or destroyed
demyelination
This is the name given to the characteristic lesion of MS. When the disease is active, myelin destruction occur in localized patches. The stripped sections appear as greyish-coloured spots in the white matter.
Plaque
This is (1) the major supporting and structural cells in CNS tissue, migrate to the site. Their role is to react to the injury by congregating together and synthesizing fiber processes to form a living scar known as (2)
(1)Astrocytes; (2) gliosis
How long do the symptoms of a flare-up last for?
The symptoms last for 6-8 weeks, then gradually resolve over 2-3 months. Depending on the severity of the disease, the remission may return the person to normal or near normal function, or there may be considerable dysfunction
There is a theory that at some point the person’s BBB was breached, allowing immune cells which are normally excluded to enter the CNS tissue environment. It is believed that a component of myelin called ____________ is the target of the attack.
Myelin Basic Protein
What is the cause of MS?
MS appears to be an autoimmune disease precipitated in a genetically susceptible individual by exposure to something in the environment, likely a virus
There are 3 factors believed to be linked to MS which are
1) Genetic/Inheritance
2) Geography
3) Viral
Schumacher Criteria for definite MS
1) Two seperate CNS symptons
2) Two seperate attacks (separated by at least 1 month)
3) Symptoms must involve the white matter
4) Age 10-50, although usually 20-40
5) Objective deficits are present on meurological examination
6) No other medical problem exists to explain patients condition
Factors that are predictive of a milder MS course
1) Early age of onset (first symptons prior to 40)
2) Sensory, as opposed to motor, symptoms at onset
3) Pattern of exacerbations and remissions as opposed to chronic progressive symptoms at onset
4) Female (males often experience more severe progression)
Despite the unpredictability of onset of MS there are some commonalities that often seen
Symptoms usually appear sooner in the lower limbs and remain more severe and the limbs typically progress in asymmetrical unilateral patterns, so that each limb will likely presents differently.
Optic Neuritis is a common visual symptom that often occurs unilaterally. The resulting impairment is usually a central blind spot in the visual field called
Scotoma
Blurred vision and double vision is known as
Diplopia
Eyes moving rapidly back and forth, usually horizontally, when attempting to focus on an object
Nystagmus
Visual impairment experienced as jumping images
Oscillopsia
Unilateral or bilateral, full or partial, failure of one eye to adduct while the other abducts
Internuclear opthalmoplegia
Indicating dorsal column involvement, it is tingling sensation down the back (and sometimes the extremities) when the head is flexed forward. While usually parathetic, it can also be dysesthetic (shooting pain or electric shock feelings instead of tingling).
Lhermitte’s Sign
While hearing impairments are uncommon, episodes of transitory hearing loss and ringing in the ear can occur this is also known as
Tinnitus
Rapid intermittent tonic contractions, either discretely or as part of a spastic response is common, especially at the ankle this is known as
Clonus
Movement hallucination, is a common experience and reflects abnormalities of cerebellar/brainstem pathways
Vertigo
An involuntary rapid flickering movement of the facial muscles, is fairly typical known as
Facial Myokymia
A facial muscle paralysis from loss of function in cranial nerve VII.
Bell’s Palsy
Speech impairment is very common in MS. There are two primary manifestations
1) Dysarthria - which is a problem with control (often because of spasticity) of the muscles involved in speaking;
2) Scanning speech - each word or syllable receives equal emphasis, giving the speech a mono-tonal disconnected quality.
Fatigue is considered one of the most disabling symptoms of MS due to the decline in conductivity of nerve fibers in the CNS also known as
Nerve Fiber Fatigue
Another fatigue impairment which is a related problem which stems from the need to consciously work on functions which are normally automatic
Cognitive Tiring
a sustained state of cheerfulness, happiness, and ease not based in the person’s reality, is reasonably common in more advanced cases. It is a permanent change in personality and frame of mind , as though the person has become disassociated from objective knowledge.
Euphoria
