Idiopathic generalized myokymia.

Abstract

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.

• Authors: P W Jamieson, M B Katirji
• Journal: Muscle & nerve (Muscle Nerve) Vol. 17 Issue 1 Pg. 42-51 (Jan 1994) ISSN: 0148-639X [Print] United States
• PMID: 8264701 (Publication Type: Case Reports, Journal Article)

Topics

• Adult
• Electrophysiology
• Fasciculation (complications, diagnosis, etiology, physiopathology)
• Female
• Humans
• Male
• Motor Neurons
• Muscle Cramp (etiology)
• Muscles (physiopathology)