Also found in: Dictionary, Thesaurus.
Lam·bert-Ea·ton myasthenic syn·drome (LEMS),(lam'bert ē'tŏn),
a generalized disorder of neuromuscular transmission caused by a defect in the release of acetylcholine quanta from the presynaptic nerve terminals; often associated with small cell carcinoma of the lung, particularly in elderly men with a long history of cigarette smoking. In contrast to myasthenia gravis, weakness tends to affect solely axial muscles, girdle muscles, and less often the limb muscles; autonomic disturbances, for example, dry mouth and impotence, are common; the deep tendon reflexes are unelicitable; on motor conduction studies, responses on initial stimulation are quite low in amplitude, but they show marked posttetanic facilitation after a few seconds of exercise. Lambert-Eaton syndrome is due to loss of voltage-sensitive calcium channels located on the presynaptic motor nerve terminal. See: myasthenic syndrome.
myasthenic syndromeLambert-Eaton syndrome, see there.
my·as·then·ic syn·drome(mī-as-then'ik sin'drōm)
A disorder of neuromuscular transmission marked primarily by limb and girdle weakness, absent deep tendon reflexes, dry mouth, and impotence; due to an immunologic disorder; often, especially in males, a paraneoplastic syndrome linked to small cell carcinoma of the lung.