Twitch response in a myopathy with impaired relaxation but no myotonia.
A patient with slow muscle relaxation but without accompanying motor unit or myotonic electrical activity had a unique staircase twitch response to repeated nerve stimulation. During 1-Hz stimulation, twitches recorded by measurement of the ankle dorsiflexor group displayed progressively increasing relaxation times with successive stimuli (37% increase) unlike the progressively decreasing relaxation time of the normal response (12-37% decrease). The response may be diagnostic of this unusual myopathy; the test methods are noninvasive and easily tolerated.
Quinlan
J G
JG
Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota.
Iaizzo
P A
PA
Gronert
G A
GA
Lambert
E H
EH
D000200:Action Potentials; D002118:Calcium / Q000378:metabolism; D004576:Electromyography; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology*; D009126:Muscle Relaxation / Q000502:physiology*; D009222:Myotonia / Q000503:physiopathology*; D009468:Neuromuscular Diseases / Q000503:physiopathology*; D010543:Peroneal Nerve / Q000503:physiopathology
D002118:Calcium