Lambert Eaton Myasthenic Syndrome (LEMS)

Etiology

  • Auto-antibody against presynaptic side of nmj

Risk Factors

  • Male>female
  • RA, vasculitis
  • Rare, 50% assoc w/malignancy→ in particular lung
  • Can also occur w/other autoimmune dz→ thyroid
  • Age ~60 if cancer, 30s & 60s if no malignancy

Symptoms

  • Fatigue
  • No numbness
  • Progressive weakness over mos
  • Proximal muscles > distal
  • Progresses caudal to cranial
  • Eye & facial muscles not typically affected
  • Autonomic dysfxn→ dry mouth, constipation, orthostatic lightheadedness, etc.

Physical Exam Findings

  • Proximal weakness
  • Diminished or absent reflexes