Peripheral nervous system conditions | Neuromuscular system

Peripheral nerve injuries

Injuries to the peripheral nerves due to trauma, chronic traction, compression, or shear

Definitions

Wallerian degeneration: Degeneration of the axon and myelin sheath distal to the site of an axonal interruption
Neuropathy: Degenerative changes in peripheral nerves that produce loss of motor and sensory function; caused by diabetes, nutritional deficits, or alcohol use
Mononeuropathy: Degeneration of a single nerve
Polyneuropathy: Bilateral, symmetrical involvement of peripheral nerves, typically in stocking/glove distribution
Neuropraxia: Injury to nerve causing sudden loss of function (compression injury); dysfunction can be rapidly reversed or persist for weeks
Axontomesis: Injury to a nerve interrupts the axon and causes loss of function and degeneration distal to the lesion (crush injury); regeneration is possible with or without surgical intervention
Neurotomesis: Cutting the nerve from all structures and complete loss of function; reinnervation fails without surgical intervention
Entrapment syndrome: Pressure on a nerve where it passes through an opening or over a bony prominence

Myasthenia gravis

An autoimmune disorder leading to decreased acetylcholine receptors at the neuromuscular junction, and thus a decrease in muscular contraction with repetition.

Symptoms:

Muscle weakness, especially in the eyes, face, throat, and limbs
Double vision
Drooping eyelids
Difficulty swallowing or speaking
Weakness that worsens with activity and improves with rest

Myasthenia crisis occurs when the exacerbation of symptoms progresses to the respiratory system, leading to life-threatening weakness.

Interventions for myasthenia gravis

Energy conservation techniques are the goal of the sessions
- No strength training as the patient becomes more fatigued with increased repetition of activity
Attempt to conduct therapy sessions in the morning to decrease fatigue
Avoid thermal modalities such as heat packs, whirlpool, etc.

Bell’s palsy

A lower motor neuron lesion involving cranial nerve VII (facial nerve), causing unilateral facial paralysis due to acute inflammation of unknown etiology, resulting in compression of the nerve in the temporal bone. Symptoms are worst within the first few hours or days, leading to symptoms lasting for several weeks or months.

Symptoms

Facial droop on one side of the face
Drooling from one side
Loss of taste to the anterior 2/3 of the tongue
Changes in saliva and tear production
Headache
Loss of sensation to the anterior two-thirds of the tongue
Sensory to face remains intact

Interventions for Bell’s palsy

Spontaneous recovery can occur
Corticosteroid use for inflammation
Electrical stimulation for nerve stimulation
Exercises for facial muscles
Taping of the eyelid to prevent dry eye due to the inability to close the eyelid

Guillain–Barré syndrome (GBS)

An acute autoimmune disorder in which the myelin sheath of peripheral nerves is damaged. Typically, occurs after recovery from a viral illness, causing demyelination to both cranial and peripheral nerves.

Symptoms

Causes motor and mild sensory loss distal to proximal in a symmetrical pattern
Usually begins in the legs and will ascend towards the trunk/UE
Worse prognosis if reaching the lungs and a need for mechanical ventilation
Motor/sensory loss progressively worsens over 4 4-week period and then stabilizes

**Interventions for Guillain–Barré syndrome (GBS)

Sessions focus on compensatory strategies to assist with gait and mobility
Avoidance of overstretching and overuse during acute phases of diagnosis
Strength training is performed once stabilization of the disease process occurs, with progression from isometric to concentric to eccentric activities