title: "Seronegative" anti-MUSK positive myasthenia gravis presenting during pregnancy.
abstract: Myasthenia gravis is an autoimmune disease characterized by weakness and fatigue of the skeletal muscles of the face and extremities. Pregnancy is associated with 19-41% of exacerbations. We present a 19-year-old woman who was seen at the neurology clinic 10 days after her last cesarean section with diplopia and trouble swallowing liquids and solids for the previous 3 months. On examination she had slurred speech, bilateral palpebral ptosis, and mild droop of her shoulders. An arterial blood sample showed a PCO2 of 50 mmHg and a PO2 of 70 mmHg. The tensilon test was positive, Intravenous methylprednisolone and immunoglobulin and oral pyridostigmine effectively relieved her myasthenic signs and symptoms. Five assays for acetylcholine or anti-striational antibodies in her serum were negative. A test for muscle-specific tyrosine kinase antibody was positive. In 10-20% of patients with myasthenia gravis no antibodies to acetylcholine receptors are detectable. Forty percent of this group has an antibody to muscle-specific tyrosine kinase.
authors.affiliation: Department of Medicine, Universidad Central del Caribe, School of Medicine, Bayamón, PR.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Terrero
authors.forename: José
authors.initials: J
authors.lastname: Ramírez-Rivera
mesh_terms: D000906:Antibodies / Q000097:blood*; D005260:Female; D006801:Humans; D009157:Myasthenia Gravis / Q000097:blood* / Q000276:immunology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood*; D020794:Receptor Protein-Tyrosine Kinases / Q000276:immunology*; D011950:Receptors, Cholinergic / Q000276:immunology*; D055815:Young Adult
chemical_list: D000906:Antibodies; D011950:Receptors, Cholinergic; C095714:MUSK protein, human; D020794:Receptor Protein-Tyrosine Kinases