Lambert-Eaton myasthenic syndrome

Background

• Paraneoplastic syndrome of weakness that is associated primarily with small cell lung cancer, other solid cancers, or lymphoproliferative diseases
• Can be non-paraneoplastic (primary autoimmune)
• Pathophysiology is decreased acetylcholine release from the presynaptic nerves

Clinical Manifestations

• Slowly progressive proximal muscle weakness without significant atrophy
• Legs often more than arms
• Recovery of lost DTRs with exercise or muscle activation (postexercise/postactivation facilitation)
• Autonomic dysfunction can include dry mouth, slow pupillary light reflex, and erectile dysfunction
• Can affect cranial nerves
• Can cause respiratory failure late in the course