Differential diagnosis of peripheral nervous system | 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 stoking/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 nerve interrupting the axon and causing 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 structure and complete loss of function; reinnervation fails without surgical intervention
Entrapment syndrome: Pressure on 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 exacerbation of symptoms progresses to the respiratory system leading to life-threatening weakness.

Interventions for myasthenia gravis

Energy conservation techniques are goal of sessions
- No strength training as patient becomes more fatigued with increased repetition of activity
Attempt to conduct therapy sessions in 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 nerve in 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 face
Drooling from one side
Loss of taste to anterior 2/3 of tongue
Changes in saliva and tear production
Headache
Loss of sensation to anterior two-thirds of 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 eyelid to prevent dry eye due to inability to close eyelid

Gullian-barre syndrome (GBS)

An acute autoimmune disorder in which peripheral nerves are damaged. Typically, occurs after recovery from viral illness causing demyelination to both cranial and peripheral nerves.

Symptoms

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

Interventions for Gullian-barre syndrome

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