Lambert-Eaton syndrome (Q41419)

Lambert-Eaton myasthenic syndrome, 20 times as rare as acetylcholine receptor positive myasthenia gravis with a prevalence of 3.42 per million, is an immune-mediated disease of the neuromuscular junction. Clinically the disease is characterised by proximal weakness of the legs. In most patients, the weakness extends to other muscles including the oculobulbar ones. Autonomic symptoms (dry mouth, erectile dysfunction, constipation) are frequent. Tendon reflexes are reduced. Repetitive nerve stimulation shows low compound muscle action potentials, decrement > 10% at low frequency and increment > 100% after maximum voluntary contraction at high frequency.