Differential diagnosis of peripheral nervous 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

Guillain-Barré 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 Guillain-Barré 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