Pns and Bell’s palsy Flashcards
Disorder of pns
Affecting cell body of alpha motor neuron in SC or BS, axon from peripheral nerve, motor end plate of nerve and muscle fibers that the motor nerve innervates
S/s of peripheral nerve (LMN)
Decreased/absent muscle tone Decreased/absent reflexes Ipsi paresis or paralysis Muscle fibrillations and fasciulations Neurogenic atrophy
UMN signs
Disturbance of selective movement control
- Abnormal mass synergies
- Hyperreflexia
- Spasticity
- Clonus
- Paresis
Neurapraxia
Reduction/complete blockage of condition across segment of nerve while axonal continuity is maintained and nerve condition is preserved
Compression
Axonotmesis
Interruption of axon w/ preservation of surrounding CT around axon
Stretch injury
Neurotmesis
Both nerve and sheath disrupted
Neurapraxia repsonse to injury
Rapid demyelination by Schwann cells
Shorter intermodal distance - nerve conduction does not return to normal
Axonotmesis or neurotemsis recovery
Wallerian degeneration and anterograde degeneration of axon
-
Nerve healing events
- Sensory nerve body cells in dorsal root canglia produce axoplasm to fill endometrial tubes
- Size important
- Smallest C fibers regenerate fastest=pain perception first
- Proximal section must grow across lesion site before demyelination occurs
Average speed of regeneration for nerves
1 mm per day
Or 1 in per month
Bell’s palsy
Common condition where facial nerve unilaterally affected
Common age for Bell’s palsy
15-45
DM and pregnant have increased incidence
prior to onset of Bell’s palsy
Severe pain in mastoid or sensation of fullness may be present
Bell’s palsy inflammation creates
Compression of facial nerve in auditory canal resulting in demyelination
Bell’s palsy EMG most effective
After 1 weeks
LMN vs UMN facial weakness
UMN close eye and wrinkle forehead, no smile
LMN unable to close eye, wrinkle forehead or smile
UMN vs LMN forehead
In UMN voluntary control of muscles of forehead spared
Left CVA will cause
Right sided lower face weakness
Damage to right facial nerve
Bell’s palsy
Right sided upper and lower face weakness
Bell’s palsy clinical manifestation
Sensory and autonomic fibers innervates for
Taste
Lacrimation
Salivation
I flexion proximal to where fibers of chorda tympani enter facial nerve
Pt will have loss of taste on affected side
Bell’s palsy clinical s/s
Unilateral facial paralysis that develops rapidly Corner of mouth droops Eyelid does not close Dry eye, lacking of tearing Loss of taste on affected side Reduced/thicker saliva on affected side
Corticosteroids and Bell’s palsy
No later than 10 days after onset of symptoms
Administered for 5 days
Antiviral may be helpful as well secondary to herpes
100% recovery obtained if tx began
W/in 3 days
If tx delayed until day 4
Prognosis dropped to 86%
Bell’s palsy -protection of
Cornea critical
Eye patch or classes
Artificial tears
For incomplete involvement recovery is usually complete and occurs in
3 weeks
For complete involvement recovery is
Longer
75% recover normal motor function
Factors associated w/ poorer outcome
Age >60
Systemic disease like DM, HTN
Lesions w/ autonomic involvement
Bell’s palsy and PT
Facial neuromuscular re-ed.
Estim can be disruptive to reinnervation
Max effort facial activation exercise can lead to synkinesis or mass action
Synkinesis
Abnormal synchronization of multiple facial movements
- thought to occur when facial nerve fibers implant into incorrect muscles as healing occurs
- crocodile tears when facial nerve crosses autonomic branch of superior pterosaurs nerve, when face contracts, tears appear
Bell’s palsy PT initiation
Drooped resting posture, minimal movement, marked functional problems
Tx w/ AAROM (position w/ fingers then attempt to hold)
3-4 x /day
Bell’s palsy pt facilitation
Minimal droop at rest, mild to mod weakness
AROM and resistive- maintain symmetry avoid synkinesis
High reps 1-2x/day
Bell’s palsy pt Movement control
Demonstrating synkinesis and continued mild to moderate facial weakness
Isolated and matched movements
Quality not quantity w/ high frequency
Bell’s palsy pt relaxation
Resting facial tension, twitches/spasms
Massage and stretching
Low to mod reps performed as needed
Surface EMG biofeedback in Bell’s palsy
Can be used to record and display small changes in muscle activity that cannot be seen in a mirror
Work on abnormal movement patterns or synkinesis
