Lambert-Eaton Myasthenic Syndrome - pathophysiology, signs and symptoms and treatment

Lambert- Eaton Myasthenic Syndrome (LEMS) is a neuromuscular junction disorder that was described by Lambert, Eaton and Rooke in the 1950s. It is a disorder of calcium voltage gated channels in the preysynaptic motor neurons. The motor neurons supply the skeletal muscles. The voltage gated calcium channel do not allow calcium influx causing reduced Acetylcholine release into the synaptic cleft and thus reduced muscle contraction. LEMS causes muscle weakness which interestingly improves with activity unlike the other neuromuscular junction disorder myasthenia gravis which manifests as muscle fatigability. Lambert Eaton syndrome is a paraneoplastic syndrome because of its close association with small cell lung cancer. Paraneoplastic syndromes are symptoms that occur at sites distant from a tumour or its metastasis.