2.23 GBS, MG

Question 1

syndrome

Answer 1

multitude of s/s that we haven’t been able to link to a single cause

Question 2

What causes GBS?

Answer 2

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

Question 3

How is GBS diagnosed?

Answer 3

diagnosis by elimination (rule out everything else)

Question 4

GBS phases

Answer 4

• acute phase (2-4 weeks)
• plateau phase (2-4 weeks)
• recovery phase (months to a year)

Question 5

some GBS symptoms

Answer 5

• weakness/paralysis
• bowel/bladder
• sensory loss (acute)

Question 6

GBS and acute sensory loss

Answer 6

• starts glove and stocking sensory and motor loss
• course is distal to proximal
• vast majority recover from this

Question 7

ANS demyelination and GBS

Answer 7

ANS demyelination is very rare (HR, breathing, etc.)

Question 8

pace of GBS demyelination

Answer 8

nerves are demyelinated quickly, both in somatic and autonomic

Question 9

progression of GBS

Answer 9

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

Question 10

Why can’t you push a GBS pt too hard? What is the PT focus and timing?

Answer 10

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

Question 11

What should be done if GBS has reached the trunk?

Answer 11

breathing will need to be checked if it has reached their trunk

Question 12

GBS bottoming out

Answer 12

• once they bottom, they hit a plateau

- myelin starts coming back

Question 13

treatment for acute GBS

Answer 13

medical team may perform plasmapheresis

• plasma has immunoglobulins in it
• healthy plasma can slow or stop acute phase if caught early enough

Question 14

What is happening in the plateau phase of GBS?

Answer 14

• demyelination has stopped

- slowly remyelinating proximal to distal

Question 15

PT during plateau phase

Answer 15

• 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)

Question 16

recovery phase of GBS

Answer 16

• slow progression
• takes months to a year to regain full strength
• remember to stop once they get fatigue

Question 17

What is myasthenia gravis?

Answer 17

• grave muscle weakness

- autoimmune disorder

Question 18

Why does MG happen?

Answer 18

• antibodies decide to start blocking ACh receptor site at a NM junction for muscle contraction
• As time goes on, antibodies destroy receptor sites

Question 19

What happens when antibodies block receptor sites initially?

Answer 19

• initially have some muscle activity

- repetitive use of the muscle » decreased ACH in receptor site » fatigue/weakness

Question 20

diagnosing MG

Answer 20

• often takes a long time for a pt to be diagnosed

- may have waxing and waning presentation

Question 21

MG: What happens once antibodies destroy receptor sites?

Answer 21

get downregulation due to disuse

Question 22

Which muscles will be most affected by MG?

Answer 22

• harder to see a noticeable change in larger muscles (more NMJ, more ACH)
• easier to see this in the face or eyelids

Question 23

How might a PT diagnose MG?

Answer 23

• have them hold a tight contraction for a period, will get eyelid droop
• muscles can’t fire anymore

Question 24

What are other ways to test for MG?

Answer 24

• blood panel to test for MG: antibodies

- may be able to test EMN/NCV

Question 25

Is MG a something that PTs can treat?

Answer 25

No. NMJ problem, not PT

Question 26

How is MG treated?

Answer 26

• they are put on cholinesterase inhibitors to prevent breakdown of ACH in the NMJ
• meds: mestinon, prostigmin
• meds become less effective over time
• for some pts, thymectomy will get rid of MG