title: Anti-MuSK myasthenia gravis with prolonged remission.
abstract: Myasthenia gravis (MG) with antibodies against muscle-specific tyrosine kinase (MuSK) is a rare disorder of neuromuscular transmission affecting preferentially bulbar, neck and respiratory muscles. We report the case of a 22-year-old man who presented with diplopia on lateral gaze to both sides, facial diplegia, nasal dysarthria and dysphagia. Repetitive nerve stimulation of the trapezius and orbicularis oculi muscles showed amplitude decrements of 19% and 41% respectively supporting the diagnosis of myasthenia gravis. MUsK antibodies were positive. Corticosteroids were introduced and then tapered and discontinued at 6 months after initiation. The patient remained in remission and asymptomatic for 4 years without ongoing treatment or prior treatment with rituximab after this first relapse of MuSK-MG. MuSK- MG is considered a hard-to-treat condition and patients generally remain dependent on immunosuppression or prior treatment with rituximab. Our observation highlights that patients with MuSK-MG can have a benign course and that continued immunosuppressive or immunomodulatory therapy may not always be required.
authors.affiliation: Department of Neurology, Rouen University Hospital and University of Rouen, France.
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Bouwyn
authors.affiliation: Department of Neurophysiology, Rouen University Hospital and University of Rouen, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Magnier
authors.affiliation: Department of Neurology, Rouen University Hospital and University of Rouen, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Bédat-Millet
authors.affiliation: Department of Neurology, Rouen University Hospital and University of Rouen, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Ahtoy
authors.affiliation: Department of Neurology, Rouen University Hospital and University of Rouen, France; INSERM U1073, Rouen, France.
authors.forename: David
authors.initials: D
authors.lastname: Maltête
authors.affiliation: Department of Neurology, Rouen University Hospital and University of Rouen, France. Electronic address: romain.lefaucheur@chu-rouen.fr.
authors.forename: Romain
authors.initials: R
authors.lastname: Lefaucheur
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D001323:Autoantibodies / Q000378:metabolism*; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D009157:Myasthenia Gravis / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology*; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology*; D011950:Receptors, Cholinergic / Q000276:immunology*; D012074:Remission Induction; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones; D001323:Autoantibodies; D011950:Receptors, Cholinergic; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases
keywords: Benign course; MuSK; Myasthenia Gravis