L5 Demyelinating Diseases Flashcards
Peripheral Nerve Demyelinating Diseases
spectrum of diseases that all result in disruption in axon and glial cells, particularly schwann cell function, and result in peripheral nerve demyelination
Causes of demyelination diseases
infectious agents
genetic predisposition
immune-related mechanisms
Guillain-Barre Syndrome
acute idiopathic autoimmune demyelinating disease of PNS
rare, incidence of .8-1.9/100,000
incidence increases with age
no difference in incidence by race
Cause of GBS
cause is unknown
most cases are preceded by GI or upper respiratory tract infections
some cases are caused by trauma, surgical interventions, treatment with monclonal antibodies and vaccination
Variants of GBS
acute inflammatory demyelinating polyradiculopathy (AIDP)
acute motor axonal neuropathy (AMAN)
AIDP
myelin is the primary target for autoimmune injury, axons can be secondarily injured
more common variant in north america and europe
AMAN
axons are the primary target for autoimmune injury
more common in asia
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)
similar to GBS, but its clinical course is chronic with relapses
onset is insidious and occurs more in older adults
treatment includes glucocorticosteroids, plasmapheresis, IVIg
Charcot Marie Tooth Disease
-rare, inherited form of neuropathy
-gene abnormalities disrupt the structure and functions of schwann cell and peripheral nerve axons
-can affect motor or sensory nerves
-no cure
S/S of CMT
Symptoms don’t become noticeable until adulthood
foot drop, pes cavus, hammer toes
Treatment of CMT
managing functional deficits with rehab and orthotics
surgery to stabilize ankle/foot
management of neuropathic pain
AIDP Disease course
-can be mild to severe in clinical symptoms
-mortality is 3-10%
-disease reaches its low point by 4 weeks; symptoms plateau and recovery begins
-recovery can begin earlier with administration of plasmapheresis or immunoglobin
CIDP disease course
cyclical relapse of symptoms, with progressive worsening in severity of symptoms over time because PN cannot fully repair
Charcot Marie Tooth disease course
no symptoms until adulthood and then progressive degeneration of PN causes worsening symptoms
CP of AIDP
-symmetric paralysis and paresthesia start distally and ascend proximally over the course of hours to days
artificial ventilation may be needed, severe pain is common, and autonomic dysfunction can happen
Management of AIDP
- assisted respiratory ventilation
- manage immobility (pressure ulcers, thrombosis, etc)
- management of pain
- monitoring for autonomic dysfunction
- plasma exchange and IV immunoglobulin to improve recovery time
Axonal regeneration
occurs slower than peripheral nerve remyelination
speed is limited by the axonal transport, which is very slow, only about 1-3 mm a day
Peripheral Nerve Recovery
PN remyelination is functionally effective process with good prognosis for recovery
can see 5/5 muscle strength within 6 months
Prognosis of AIDP
-most pts experience functional recovery within 12 months after disease onset
-few patients have residual impairments
-rehab is key to optimizing functional outcomes for all patients
Poor prognosis for AIDP has been linked to
> 40 years old
preceding diarrhea/ C jejuni infection
high disability after nadir
-2% of pts may develop CIDP
-20% of pts with GB won’t walk unaided 6 months after onset
GBS and exercise research
insufficient high quality literature
cannot make conclusions about the physical outcomes after exercise interventions
Muscle fibers and GBS
when myelin is damaged, the impusle is not as efficient, decreasing the number of muscle fibers that can be recruited to perform voluntary movement
Overwork weakness
a decrease in absolute force production and endurace of a muscle that is prolonged because of excessive activity
partially denervated muscles are at risk for OW which may lead to further motor unit damage that may not be reversible
How to avoid overwork weakness
- avoid eccentric exercises throughout all stages of recovery
- monitor for pain/stiffness, increased paresthesia, DOMS
- Provide adequate rest between sets
- Reduce workload intensity
If muscle strength <3/5 (acute phase)
intensity = AAROM to submaximal. exercise is non-fatiguing
mode = functional task training
frequency = <3 days a week
consider braces/orthosis for joint protection
Muscle strength is ≥ 3/5 but fatigues (sub-acute phase)
Intensity = >1 set of 10-15 reps at 60-70% 1 ROM
Progression = 2-5% increase once pt can lift 2 sets of 15 reps without signs of OW for 2 consecutive sessions
Mode = functional, low resistance band, light free weights, aquatic
Frequency = 2-3 times/wk for each major muscle group
Muscle strength >3/5 with minimal to no signs of overwork weakness (recovery phase)
progress to ACSM strengthening guidelines
intensity = 60-80$ of 1 RM
mode = free weight, machine, band
frequency = 2-3 wk
Recovery of strength…
occurs in a descending patter, with distal muscles recovering slowest
