title: Distal myasthenia gravis with a decrement, an increment, and denervation.
abstract: We present two patients with distal myasthenia gravis poorly responsive to immunomodulatory therapy. In addition to a typical decrement on slow repetitive nerve stimulation, both had borderline to low compound muscle action potential (CMAP) amplitudes, a large increment in CMAP amplitude and area after exercise, and active denervation in distal muscles. Both had elevated acetylcholine receptor antibody (AChR Ab) levels, but normal voltage-gated calcium channel antibody levels. We hypothesize that these electrophysiological findings represent a more severe form of myasthenia gravis.
authors.affiliation: From the EMG Laboratory and Neuromuscular Disease Center, Department of Neurology, University of Rochester School of Medicine and Dentistry, Rochester, New York.
authors.forename: W S
authors.initials: WS
authors.lastname: Musser
authors.forename: R L
authors.initials: RL
authors.lastname: Barbano
authors.forename: C A
authors.initials: CA
authors.lastname: Thornton
authors.forename: R T
authors.initials: RT
authors.lastname: Moxley
authors.forename: D N
authors.initials: DN
authors.lastname: Herrmann
authors.forename: E L
authors.initials: EL
authors.lastname: Logigian