Jean-Christophe Antoine1, Florence Robert-Varvat2, Thierry Maisonobe3, Alain Créange4, Jérôme Franques5, Stéphane Mathis6, Emilien Delmont5, Thierry Kuntzer7, Jean-Pascal Lefaucheur4, Jean Pouget5, Karine Viala3, Claude Desnuelle8, Andoni Echaniz-Laguna9, Francesco Rotolo2, Jean-Philippe Camdessanché10. 1. Centre de Référence Maladies Neuromusculaires Rares Rhône-Alpes, CHU de Saint-Etienne, France; Université de Lyon, Saint-Etienne, France; INSERM U1028, Centre des Neurosciences de Lyon, Lyon, France. Electronic address: j.christophe.antoine@chu-st-etienne.fr. 2. Centre de Référence Maladies Neuromusculaires Rares Rhône-Alpes, CHU de Saint-Etienne, France. 3. Centre de Référence Maladies Neuromusculaires Rares, Hôpital de la Salpêtrière, Paris, France. 4. Service de Neurologie, Hôpital Henri Mondor, Créteil, France. 5. Centre de Référence des Maladies Neuromusculaires et de la SLA, Hôpital de La Timone, Marseille, France. 6. Service de Neurologie, CHU de Poitiers, France. 7. Unité Nerf-Muscle, Service de Neurologie, Département des Neurosciences Cliniques, Centre Hospitalier Universitaire Vaudois, Université de Lausanne, Lausanne, Switzerland. 8. Centre de Référence des Maladies Neuromusculaires et SLA, CHU de Nice, France. 9. Service de Neurologie, CHU de Strasbourg, France. 10. Centre de Référence Maladies Neuromusculaires Rares Rhône-Alpes, CHU de Saint-Etienne, France; Université de Lyon, Saint-Etienne, France; INSERM U1028, Centre des Neurosciences de Lyon, Lyon, France.
Abstract
BACKGROUND: Patients with inflammatory sensory neuronopathy (SNN) may benefit from immunomodulatory or immunosuppressant treatments if administered timely. Knowing the temporal profile of neuronal loss in dorsal root ganglia will help to ascertain whether a final diagnosis may be reached before the occurrence of irreversible neuronal injuries. Thus, we addressed the evolution of neuronal loss in SNN by using sensory nerve action potentials (SNAPs) as a surrogate marker of neuron degeneration. METHODS: Eighty-six patients with acute/subacute inflammatory SNN (paraneoplastic, associated with dysimmune diseases, or idiopathic) were retrospectively studied. The monthly SNAP reduction was determined and normalized with the lower limit of normal. Disability progression was expressed by the modified Rankin score and correlated with SNAP reduction. RESULTS: The monthly SNAP reduction was similar in the four limbs although the median nerve was less severely affected. The monthly SNAP reduction was very severe within the first two months of evolution, began to slow down after seven months, and stabilized after ten months. It was tightly correlated with disability progression. Kaplan-Meier analysis showed that the median time until matching the diagnostic criteria of SNN was 8.5 months. Within this period, 42% of nerves remained excitable. CONCLUSIONS: Developing treatment aiming at the stabilization of SNN is possible within the first 8 months of evolution. An improvement of the disease is possible if patients are treated within two months, which needs an early referral to an expert center and ENMG testing of the radial and ulnar nerves, which are most sensitive to changes.
BACKGROUND:Patients with inflammatory sensory neuronopathy (SNN) may benefit from immunomodulatory or immunosuppressant treatments if administered timely. Knowing the temporal profile of neuronal loss in dorsal root ganglia will help to ascertain whether a final diagnosis may be reached before the occurrence of irreversible neuronal injuries. Thus, we addressed the evolution of neuronal loss in SNN by using sensory nerve action potentials (SNAPs) as a surrogate marker of neuron degeneration. METHODS: Eighty-six patients with acute/subacute inflammatory SNN (paraneoplastic, associated with dysimmune diseases, or idiopathic) were retrospectively studied. The monthly SNAP reduction was determined and normalized with the lower limit of normal. Disability progression was expressed by the modified Rankin score and correlated with SNAP reduction. RESULTS: The monthly SNAP reduction was similar in the four limbs although the median nerve was less severely affected. The monthly SNAP reduction was very severe within the first two months of evolution, began to slow down after seven months, and stabilized after ten months. It was tightly correlated with disability progression. Kaplan-Meier analysis showed that the median time until matching the diagnostic criteria of SNN was 8.5 months. Within this period, 42% of nerves remained excitable. CONCLUSIONS: Developing treatment aiming at the stabilization of SNN is possible within the first 8 months of evolution. An improvement of the disease is possible if patients are treated within two months, which needs an early referral to an expert center and ENMG testing of the radial and ulnar nerves, which are most sensitive to changes.