Adalimumab-induced myasthenia gravis: case-based review

Abstract

Myasthenia gravis (MG) is an autoimmune disease characterised by the presence of acetylcholine receptor antibodies and by blocking the transmission of the signal in the neuromuscular junction causing muscle weakness. It can be associated with several autoimmune diseases and certain drugs, between them Etanercept an anti-tumour necrosis factor (TNF) agent. A 42-year-old woman with rheumatoid arthritis (RA) refractory to methotrexate, was treated with adalimumab (ADA), a human monoclonal antibody against the TNF, in a dosage scheme of 40 mg every 14 days subcutaneously. The patient responded well to ADA therapy with sustained remission for 18 months when she developed blurred vision and eyelid ptosis of the left eye. The diagnosis of ocular MG was made. ADA has been discontinued and she started a treatment with pyridostigmine showing an excellent response and complete remission within a 2-month period. This is the first report making an association of ADA and ocular MG. Thus, rheumatologists dealing with patients treated with TNF inhibitors should be aware of the possible development of neurological adverse events, among them MG.

Keywords: Adalimumab; Anti-TNFα; Etanercept; Muscle weakness; Myasthenia gravis; Neuromuscular junction.