title: Musk-antibody positive myasthenia gravis presenting with isolated neck extensor weakness.
abstract: Dropped head sign is characterized by the gradual forward sagging of the head due to weakness of neck extensor muscles. This may be a prominent sign of several neuromuscular disorders and may be an isolated feature of myasthenia gravis (MG). We describe a patient with isolated neck extensor weakness, eletrophysiological findings suggesting myasthenia gravis and positive MuSK antibodies. This case supports that finding anti-MuSK antibodies may be extremely helpful in dropped head patients and negative acetylcholine receptor antibodies especially if needle EMG does not reveal myopathic or neurogenic patterns.
authors.affiliation: Neuromuscular Unit, Department of Neurology, Hospital Universitari de Bellvitge-IDIBELL, Feixa Llarga S/N 08907, L'Hospitalet de Llobregat, Barcelona, Spain. carloscasasnovas@csub.scs.es
authors.forename: C
authors.initials: C
authors.lastname: Casasnovas
authors.forename: M
authors.initials: M
authors.lastname: Povedano
authors.forename: S
authors.initials: S
authors.lastname: Jaumà
authors.forename: J
authors.initials: J
authors.lastname: Montero
authors.forename: J A
authors.initials: JA
authors.lastname: Martínez-Matos
mesh_terms: D000200:Action Potentials / Q000502:physiology / Q000528:radiation effects; D000906:Antibodies / Q000097:blood; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography; D005260:Female; D006801:Humans; D008875:Middle Aged; D018908:Muscle Weakness / Q000503:physiopathology*; D009157:Myasthenia Gravis / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D009334:Neck Muscles / Q000503:physiopathology*; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology*; D011950:Receptors, Cholinergic / Q000276:immunology*
chemical_list: D000906:Antibodies; D011950:Receptors, Cholinergic; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases