Electrodiagnostic Abnormalities Associated with Fibromyalgia

Abstract

Mieke Hulens,1 Frans Bruyninckx,2 Ricky Rasschaert,3 Greet Vansant,4 Peter De Mulder,5 Ingeborg Stalmans,6,7 Chris Bervoets,8,9 Wim Dankaerts1 1Department of Rehabilitation Sciences, Musculoskeletal Rehabilitation Research Unit, Faculty of Kinesiology and Rehabilitation Sciences, University of Leuven, Leuven, Belgium; 2Clinical Electromyography Laboratory, University Hospitals UZ Leuven, Leuven, Belgium; 3Department of Neurosurgery, AZ Rivierenland, Bornem, Belgium; 4Department of Social and Primary Health Care, Public Health Nutrition, University of Leuven, Leuven, Belgium; 5Department of Anesthesiology and Pain Therapy, Imelda Hospital, Bonheiden, Belgium; 6Department of Neurosciences, Ophthalmology Research Group, University of Leuven, Leuven, Belgium; 7Department of Ophthalmology, University Hospitals UZ Leuven, Leuven, Belgium; 8Department of Neurosciences, Adult Psychiatry, University of Leuven, Leuven, Belgium; 9Department of Adult Psychiatry, University Psychiatric Center UPC KULEUVEN, Leuven, BelgiumCorrespondence: Mieke Hulens Overwegstraat 14, Sint-Joris-Weert 3051, BelgiumTel [phone]Fax [phone]Email [email protected]: Increasing evidence suggests that fibromyalgia most likely represents a neurological dysfunction. We previously hypothesized that at least some fibromyalgia cases may be caused by irritation of nerve root fibers and sensory neurons due to moderately increased cerebrospinal pressure. Because of the rostro-caudal hydrostatic pressure gradient, neurogenic abnormalities are expected to be most pronounced in sacral nerve roots. The purpose was to review electrodiagnostic tests of patients with fibromyalgia.Methods: A retrospective review of electrodiagnostic test results, including the lumbar and sacral nerve root myotomes of patients diagnosed with fibromyalgia according to the 1990 criteria of the American College of Rheumatology was done.Results: All 17 patients were female. Sural nerve responses could not be elicited in 12% and S1-Hoffmann reflex latencies were increased in 41%. In 12% of the patients, fibular motor nerve distal latency and conduction velocity were outside normal limits. Needle-EMG revealed neurogenic motor unit potentials in 0% of L2, 6% of L3, 29% of L4, 71% of L5, 47% of S1, 94% of S2, and 76% of S3-S4 myotomes. S3-S4 nerve-supplied anal reflexes were delayed in 94%.Conclusion: This is the first time that electrodiagnostic data of both lumbar and sacral nerve root myotomes in fibromyalgia patients are presented. All patients showed neurogenic abnormalities that were more pronounced in the sacral than in the lumbar myotomes with a rather patchy distribution pattern. We propose that, in addition to skin punch biopsies to assess small fiber neuropathy, assessment of the anal reflex may be a useful part of the diagnostic pathway in patients with fibromyalgia.Keywords: large fiber neuropathy, anal reflex, sacral nerves, nerve conduction studies, needle EMG

Keywords

• large fiber neuropathy
• anal reflex
• sacral nerves
• nerve conduction studies
• needle emg