title: Small fibre impairment predicts neuropathic pain in Guillain-Barré syndrome.
abstract: The mechanisms of neuropathic pain (NP) in Guillain Barré syndrome (GBS) are currently unknown. It has recently been shown that acute neuropathy of GBS not only affects large myelinated fibres but also small nociceptive fibres. In this prospective longitudinal 18 months study, we investigated the role of small fibre impairment in NP in GBS (n=30). Small fibres were assessed by quantifying cold and warm detection and pain thresholds and responses to suprathreshold painful thermal and mechanical stimuli. Nerve conduction velocities and mechanical detection thresholds assessed large myelinated fibres. Detection thresholds particularly at the lower limbs were significantly impaired in patients with GBS compared to 15 healthy controls. GBS patients with NP (n=13) had more severe impairment of cold detection thresholds (p=0.04), heat pain thresholds (p=0.03) and responses to suprathreshold heat stimuli (p=0.017) in the foot compared with those without pain or with non-neuropathic pain (n=17). Large fibre dysfunction and motor disability were similar between groups. Small fibre sensory impairment at the acute stage was correlated with the intensity of burning pain (Rho: -0.72; p=0.01 for cold detection; Rho: 0.72; p=0.02 for heat pain) and predicted residual NP (odds 4.1 p=0.04 for heat pain). These findings emphasize the importance of nociceptive fibre impairment in NP in GBS at both acute and chronic stages and suggest similarities between the mechanisms of NP in GBS and those of small fibre painful sensory polyneuropathies.
authors.affiliation: Université de Versailles St-Quentin, AP-HP, Hôpital Raymond Poincaré, Service d'Anesthésie Réanimation Chirurgicale, 104 boulevard Raymond Poincaré, 92380 Garches, France Université de Versailles St-Quentin, AP-HP, Hôpital Raymond Poincaré, Réanimation médico-chirurgicale, 104 boulevard Raymond Poincaré, 92380 Garches, France INSERM, U-987, Hôpital Ambroise Paré, AP-HP, Centre d'Evaluation et de Traitement de la Douleur, 9 avenue Charles de Gaulle, Boulogne-Billancourt F-92100, France Université Versailles Saint-Quentin, Versailles F-78035, France.
authors.forename: Valéria
authors.initials: V
authors.lastname: Martinez
authors.forename: Dominique
authors.initials: D
authors.lastname: Fletcher
authors.forename: Frédéric
authors.initials: F
authors.lastname: Martin
authors.forename: David
authors.initials: D
authors.lastname: Orlikowski
authors.forename: Tarek
authors.initials: T
authors.lastname: Sharshar
authors.forename: Marcel
authors.initials: M
authors.lastname: Chauvin
authors.forename: Didier
authors.initials: D
authors.lastname: Bouhassira
authors.forename: Nadine
authors.initials: N
authors.lastname: Attal
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D005260:Female; D020275:Guillain-Barre Syndrome / Q000150:complications* / Q000473:pathology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology* / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology; D009437:Neuralgia / Q000209:etiology*; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000502:physiology; D010525:Peripheral Nerves / Q000503:physiopathology*; D010812:Physical Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult