Antibodies to AChR, MuSK and VGKC in a patient with myasthenia gravis and Morvan's syndrome

Background A 46-year-old woman presented to a local hospital with acute respiratory failure and a 2-year progressive history of fatigue, personality changes, increased sweating, dysphagia with substantial weight loss, dysarthria, and intermittent ptosis and diplopia. Neurological examination showed facial weakness, lingual atrophy and bulbar palsy, which necessitated the use of a feeding tube and ventilatory support. Mild limb weakness with severe muscle atrophy and diffuse muscle twitches were observed. The patient had also developed visual hallucinations and persecutory delusions. Her personal and family medical histories were unremarkable. Investigations Sensory and motor nerve conduction studies, repetitive nerve stimulation, electromyogram, blood-cell counts, general chemistry and metabolic function tests, a CT scan, an [18(F)]fluorodeoxyglucose-PET scan, and tests for serum antibodies to acetylcholine receptors, muscle- specific tyrosine kinase, voltage-gated potassium channels, P/Q-type voltage-gated calcium channels, and paraneoplastic antigens, were carried out. Diagnosis Myasthenia gravis associated with antibodies to acetylcholine receptor and muscle-specific tyrosine kinase, and Morvan's syndrome associated with antibodies to voltage-gated potassium channels in the absence of thymoma. Management Combined treatment with prednisone, intravenous immunoglobulin, ciclosporin, and rituximab.