Lambert-Eaton myasthenic syndrome

Lambert-Eaton myasthenic syndrome is a rare disorder that affects the nervous system, specifically the connection between nerves and muscles. It causes muscle weakness, especially in the legs and hips, making activities like walking or climbing stairs difficult. This condition happens because the body's immune system mistakenly attacks the nerves that tell muscles to move. People with this syndrome may also experience dry mouth and difficulty with eye movements. The symptoms often improve temporarily with activity but worsen after rest. It mainly affects adults and can be associated with certain types of cancer.

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder characterized by impaired presynaptic calcium channel function at the neuromuscular junction due to autoantibodies against P/Q-type voltage-gated calcium channels (VGCCs). This leads to reduced acetylcholine release and subsequent muscle weakness, predominantly affecting proximal limb muscles. LEMS is often a paraneoplastic syndrome, most commonly associated with small cell lung carcinoma, but can also occur as a primary autoimmune disorder. Clinically, it presents with proximal muscle weakness, autonomic symptoms such as dry mouth, and diminished or absent deep tendon reflexes that may transiently improve with repeated muscle use. Diagnosis and management require recognition of these features and confirmation by electrophysiological and serological testing.