segmental zoster paresis

Epidemiology

• 3-5% of patients with cutaneous Herpes zoster

Clinical manifestations

• segmental weakness involving the arm or leg corresponding to distribution of nerve root(s) that give rise to the dermatomal distribution
• weakness starts within 2 weeks of cutaneous eruption
• involves proximal muscles more commonly
• limited to 2-3 myotomes
• pain may hinder examination for weakness

Diagnostic procedures

• nerve conduction studies show reduced amplitudes of action potentials in sensory & compound motor nerves
• needle electromyography 2-3 weeks after onset commonly shows abnormal spontaneous activity in weak muscles, if done later may reveal reinnervation with prolonged & polyphasic motor unit potentials

Management

• intravenous acyclovir with or without glucocorticoids, benefit of antiviral &/or glucocorticoids not established
• prognosis is good
  • generally patients recover most function
  • 50% recover all function

More general terms

• Herpes zoster (shingles)