Neuromuscular Junction Disorders in the Elderly

Abstract

The neuromuscular junction (NMJ) is unusually susceptible to disease in aging humans. Both primary autoimmune and paraneoplastic disease target the presynaptic and postsynaptic portions of the NMJ, leading to well-defined syndromes, including Lambert-Eaton myasthenic syndrome and myasthenia gravis. Primary immune disease has a bifid incidence peak, with both diseases found in younger individuals with a predilection for females and in older individuals with less or no gender specificity. Their paraneoplastic counterparts, classically identified in patients with small-cell lung carcinoma and thymomas, respectively, are much more common in older individuals. Almost 90% have onset after age 50, with 60+% of paraneoplastic disease patients being male. Although diseases of the NMJ are also diagnosed in young individuals, the lifespan of those individuals has been lengthened with available treatments, leading to specific challenges for older patients with myasthenic syndromes.