Lambert-Eaton syndrome

A generalised defect of ACh release from the presynaptic terminals (antibodies to the voltage gated calcium channels)

Tends to affect men with small cell lung cancer who've smoked for a long time (also breast... and 50% are idiopathic)

It differs from myasthenia gravis in that the muscles tend to be axial and girdle. Autonomic disturbances are found and the deep tendon reflexes are absent (though they return after exercise) - so EMG with repetition shows an improvement in response