2.23 GBS, MG Flashcards
syndrome
multitude of s/s that we haven’t been able to link to a single cause
What causes GBS?
We don’t know what causes it, but 25-40% of people have had a viral infection prior to their diagnosis
- often cytomegalovirus or epstein barr virus
How is GBS diagnosed?
diagnosis by elimination (rule out everything else)
GBS phases
- acute phase (2-4 weeks)
- plateau phase (2-4 weeks)
- recovery phase (months to a year)
some GBS symptoms
- weakness/paralysis
- bowel/bladder
- sensory loss (acute)
GBS and acute sensory loss
- starts glove and stocking sensory and motor loss
- course is distal to proximal
- vast majority recover from this
ANS demyelination and GBS
ANS demyelination is very rare (HR, breathing, etc.)
pace of GBS demyelination
nerves are demyelinated quickly, both in somatic and autonomic
progression of GBS
we don’t know when it’s going to stop
- typically within the 2-4 week range is where most people hit the peak of weakness
- they’ll be in the hospital by then
Why can’t you push a GBS pt too hard? What is the PT focus and timing?
to avoid damaging unmyelinated nerves
- PT focused on positioning, PROM, education
- will need PT at least once a day, esp if there’s trunk weakness
What should be done if GBS has reached the trunk?
breathing will need to be checked if it has reached their trunk
GBS bottoming out
- once they bottom, they hit a plateau
- myelin starts coming back
treatment for acute GBS
medical team may perform plasmapheresis
- plasma has immunoglobulins in it
- healthy plasma can slow or stop acute phase if caught early enough
What is happening in the plateau phase of GBS?
- demyelination has stopped
- slowly remyelinating proximal to distal
PT during plateau phase
- start acclimating to upright postures again
- ROM
- make sure they’re not having pressure issues
- can’t overexert them (depending on level of demyelination, may have 0-1/5 strength)
recovery phase of GBS
- slow progression
- takes months to a year to regain full strength
- remember to stop once they get fatigue
What is myasthenia gravis?
- grave muscle weakness
- autoimmune disorder
Why does MG happen?
- antibodies decide to start blocking ACh receptor site at a NM junction for muscle contraction
- As time goes on, antibodies destroy receptor sites
What happens when antibodies block receptor sites initially?
- initially have some muscle activity
- repetitive use of the muscle » decreased ACH in receptor site » fatigue/weakness
diagnosing MG
- often takes a long time for a pt to be diagnosed
- may have waxing and waning presentation
MG: What happens once antibodies destroy receptor sites?
get downregulation due to disuse
Which muscles will be most affected by MG?
- harder to see a noticeable change in larger muscles (more NMJ, more ACH)
- easier to see this in the face or eyelids
How might a PT diagnose MG?
- have them hold a tight contraction for a period, will get eyelid droop
- muscles can’t fire anymore
What are other ways to test for MG?
- blood panel to test for MG: antibodies
- may be able to test EMN/NCV
