Myasthenia Gravis (MG)

Etiology

  • Autoimmune w/ab targeting ACh receptor
  • 10% will have thymoma

Risk Factors

  • 20-30y female
  • 50-70y male

Symptoms

  • Painless
  • Subacute
  • Progressive
  • Worse w/repetitive movement, end of day
  • Ocular form: double vision, drooping eyelids, other cranial nerve palsies; may fluctuate
  • Generalized form: systemic weakness affecting neck, extremities, other muscles→ asymmetric and prox > distal fashion

Physical Exam Findings

  • No atrophy
  • Nasal speech
  • Reflexes preserved
  • No sensory findings
  • Ptosis (eyelid covering at least part of pupil)
  • Eye muscle weakness
  • Other CN palsies
  • Weakness in other muscles→ worse w/use
  • Can cause systemic weakness affecting neck, extremities, other muscles→ asymmetric, prox > distal

Links