Acquired slow-channel syndrome

We report the case of a 37-year-old man with clinical and electrophysiological features of hereditary slow-channel syndrome (SCS) and antibodies against acetylcholine receptors (AChR-Abs). He presented with weakness of shoulder and hand muscles. A supramaximal single stimulus to the motor nerves disclosed a double compound muscle action potential (CMAP). Repetitive stimulation of ulnar, suprascapular, and median nerves showed a CMAP decrement greater than 10%. The patient responded to pyridostigmine. This report confirms the importance of AChR-Ab titers in suspected cases of hereditary SCS because patients with positive AChR-Abs may have a better response to available treatments. (C) 2000 John Wiley & Sons, Inc.