Electrophysiological signs of permanent axonal loss in a follow-up study of patients with Guillain-Barré syndrome.
The neurophysiological mechanisms for persisting impairment of motor function after Guillain-Barre syndrome (GBS) were assessed in 37 unselected patients 1-13 years after diagnosis. For evaluation of reinnervation and axonal loss, macroelectromyography (macro-EMG) including measurement of fiber density (FD) was performed. Data from neuropathy symptom score, neuropathy disability score, nerve conduction studies, and quantitative sensory examination were ranked and summed to a neuropathy rank sum score (NRSS). The isokinetic muscle strength at the ankle was measured. Signs of axonal loss with increase of either macro motor unit potential (macro-MUP) amplitude or FD occurred in 76% of patients. The macro-MUP amplitude correlated with muscle strength and with NRSS. Patients with evidence of residual neuropathy had increased macro-MUP amplitude and FD as well as decreased muscle strength compared to patients without evidence of residual neuropathy. We conclude that axonal loss takes place in a substantial number of GBS patients and is associated with permanent muscle weakness caused by insufficient reinnervation. Possible patterns of pathology are discussed in relation to the macro-EMG findings.
Dornonville de la Cour
Charlotte
C
Department of Neurology, Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C, Denmark. lacour@akhphd.au.dk <lacour@akhphd.au.dk>
Andersen
Henning
H
Stålberg
Erik
E
Fuglsang-Frederiksen
Anders
A
Jakobsen
Johannes
J
D000328:Adult; D000368:Aged; D000843:Ankle Joint / Q000502:physiology; D001369:Axons / Q000473:pathology*; D003430:Cross-Sectional Studies; D004576:Electromyography; D005260:Female; D005500:Follow-Up Studies; D020275:Guillain-Barre Syndrome / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018908:Muscle Weakness / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D009416:Nerve Regeneration; D009431:Neural Conduction; D012684:Sensory Thresholds; D019415:Torque; D014732:Vibration