title: Lambert-Eaton myasthenic syndrome and follicular thymic hyperplasia in systemic lupus erythematosus.
abstract: Fatigue is a prominent feature of systemic lupus erythematosus (SLE), usually ascribed to various factors, such as muscle or joint involvement, anaemia or depression. The Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoantibody-mediated disorder of neuro-muscular transmission. We report on a well-defined LEMS associated with thymus hyperplasia in a SLE patient. An African 41 years-old SLE patient presented with persisting fatigue, myalgia and dyspnea, abolished reflexes and a bilateral ptosis. Neuromuscular electrodiagnostic study showed a clear-cut potentiation that was typical of a pre-synaptic neuromuscular junction disease. Anti-calcium gated channels antibodies were disclosed in serum and a diagnosis of LEMS was made. A total body CT-scan revealed an antero-superior mediastinal mass, compatible with thymoma. The tumour was surgically removed with a final diagnosis of follicular thymic hyperplasia. In conclusion, our observation provides a new example of entangled organ-specific and systemic autoimmunity in the context of thymus pathology. Potentiation study during electromyography should be performed systematically to rule out LEMS in patients with SLE and muscle weakness.
authors.affiliation: Department of Internal Medicine, Bichat-Claude Bernard Hospital, Paris-Diderot University, Paris, France.
authors.forename: E
authors.initials: E
authors.lastname: Pasqualoni
authors.forename: F
authors.initials: F
authors.lastname: Aubart
authors.forename: B
authors.initials: B
authors.lastname: Brihaye
authors.forename: K
authors.initials: K
authors.lastname: Sacré
authors.forename: T
authors.initials: T
authors.lastname: Maisonobe
authors.forename: J-P
authors.initials: JP
authors.lastname: Laissy
authors.forename: O
authors.initials: O
authors.lastname: Lidove
authors.forename: T
authors.initials: T
authors.lastname: Papo
mesh_terms: D000328:Adult; D005221:Fatigue / Q000175:diagnosis / Q000209:etiology; D006801:Humans; D015624:Lambert-Eaton Myasthenic Syndrome / Q000150:complications* / Q000175:diagnosis; D008180:Lupus Erythematosus, Systemic / Q000150:complications*; D008297:Male; D008435:Mauritania; D013945:Thymoma / Q000175:diagnosis / Q000601:surgery; D013952:Thymus Hyperplasia / Q000150:complications* / Q000175:diagnosis; D013953:Thymus Neoplasms / Q000175:diagnosis / Q000601:surgery; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging