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Idiopathic generalized myokymia
Author(s) -
Jamieson Patrick W.,
Katirji M. Bashar
Publication year - 1994
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880170106
Subject(s) - myokymia , myotonia , hyporeflexia , medicine , electromyography , weakness , fasciculation , muscle weakness , motor unit , muscle cramp , carbamazepine , pediatrics , anesthesia , surgery , physical medicine and rehabilitation , anatomy , epilepsy , myotonic dystrophy , psychiatry
Idiopathic generalized myokymia (IGM) is a rare, heterogeneous, and poorly understood syndrome. We present analysis of 75 reported cases in the world literature. IGM affects men and women equally, with a mean age of onset 29 ± 19 years. Patients' common presenting complaints are stiffness (60%), cramps (12%), weakness (12%), and muscle twitching (4%). Family history is positive in 30%. In addition to generalized clinical myokymia (92%), abnormal neurologic findings include: hyporeflexia (70%), weakness (45%), grip myotonia (39%), and calf hypertrophy (16%). Electrical activity consisting of spontaneous continuous motor unit activity and/or electrical myokymia was documented in all patients. When electrical myokymia was observed (66%), the grouped discharges where irregular and had an interburst frequency of 2–300 Hz. Both phenytoin and carbamazepine are effective treatments. We conclude that IGM has a wide spectrum of symptoms and severity and should be considered in all patients that present with stiffness, cramps, or muscle twitching. EMG greatly aids in diagnosis. © 1994 John Wiley & Sons, Inc.