L5 Demyelinating Diseases

Question 1

Peripheral Nerve Demyelinating Diseases

Answer 1

spectrum of diseases that all result in disruption in axon and glial cells, particularly schwann cell function, and result in peripheral nerve demyelination

Question 2

Causes of demyelination diseases

Answer 2

infectious agents
genetic predisposition
immune-related mechanisms

Question 3

Guillain-Barre Syndrome

Answer 3

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

Question 4

Cause of GBS

Answer 4

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

Question 5

Variants of GBS

Answer 5

acute inflammatory demyelinating polyradiculopathy (AIDP)

acute motor axonal neuropathy (AMAN)

Question 6

AIDP

Answer 6

myelin is the primary target for autoimmune injury, axons can be secondarily injured

more common variant in north america and europe

Question 7

AMAN

Answer 7

axons are the primary target for autoimmune injury
more common in asia

Question 8

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)

Answer 8

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

Question 9

Charcot Marie Tooth Disease

Answer 9

-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

Question 10

S/S of CMT

Answer 10

Symptoms don’t become noticeable until adulthood

foot drop, pes cavus, hammer toes

Question 11

Treatment of CMT

Answer 11

managing functional deficits with rehab and orthotics
surgery to stabilize ankle/foot
management of neuropathic pain

Question 12

AIDP Disease course

Answer 12

-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

Question 13

CIDP disease course

Answer 13

cyclical relapse of symptoms, with progressive worsening in severity of symptoms over time because PN cannot fully repair

Question 14

Charcot Marie Tooth disease course

Answer 14

no symptoms until adulthood and then progressive degeneration of PN causes worsening symptoms

Question 15

CP of AIDP

Answer 15

-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

Question 16

Management of AIDP

Answer 16

1. assisted respiratory ventilation
2. manage immobility (pressure ulcers, thrombosis, etc)
3. management of pain
4. monitoring for autonomic dysfunction
5. plasma exchange and IV immunoglobulin to improve recovery time

Question 17

Axonal regeneration

Answer 17

occurs slower than peripheral nerve remyelination

speed is limited by the axonal transport, which is very slow, only about 1-3 mm a day

Question 18

Peripheral Nerve Recovery

Answer 18

PN remyelination is functionally effective process with good prognosis for recovery

can see 5/5 muscle strength within 6 months

Question 19

Prognosis of AIDP

Answer 19

-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

Question 20

Poor prognosis for AIDP has been linked to

Answer 20

> 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

Question 21

GBS and exercise research

Answer 21

insufficient high quality literature

cannot make conclusions about the physical outcomes after exercise interventions

Question 22

Muscle fibers and GBS

Answer 22

when myelin is damaged, the impusle is not as efficient, decreasing the number of muscle fibers that can be recruited to perform voluntary movement

Question 23

Overwork weakness

Answer 23

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

Question 24

How to avoid overwork weakness

Answer 24

1. avoid eccentric exercises throughout all stages of recovery
2. monitor for pain/stiffness, increased paresthesia, DOMS
3. Provide adequate rest between sets
4. Reduce workload intensity

Question 25

If muscle strength <3/5 (acute phase)

Answer 25

intensity = AAROM to submaximal. exercise is non-fatiguing

mode = functional task training

frequency = <3 days a week

consider braces/orthosis for joint protection

Question 26

Muscle strength is ≥ 3/5 but fatigues (sub-acute phase)

Answer 26

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

Question 27

Muscle strength >3/5 with minimal to no signs of overwork weakness (recovery phase)

Answer 27

progress to ACSM strengthening guidelines

intensity = 60-80$ of 1 RM
mode = free weight, machine, band
frequency = 2-3 wk

Question 28

Recovery of strength…

Answer 28

occurs in a descending patter, with distal muscles recovering slowest