Related Experiment Videos
Penicillamine-associated myasthenia gravis
Abstract:
Electroneuromyographic studies have been reported as abnormal in only 9 of 23 cases of penicillamine-associated myasthenia gravis (MG). We report a patient with rheumatoid arthritis who developed clinical and electrodiagnostic evidence of myasthenia 7 months after beginning penicillamine therapy. Six months after discontinuing penicillamine, it was possible to discontinue anticholinesterase medications. With clinical improvement, electrodiagnostic studies (including single-fiber electrmyography) improved, serum antibody titers to human muscle acetylcholine receptor fell, and lymphocytes became more responsive to the nonspecific mitogen phytohemagglutinin. Evidence suggests that penicillamine-associated myasthenia is a distinct syndrome rather than the chance occurrence of two diseases. This syndrome is clinically and electrophysiologically distinguishable from idiopathic myasthenia only by the high remission rate after penicillamine is discontinued.
Insights
Penicillamine-associated myasthenia gravis (MG) is a distinct syndrome. This condition shows a high remission rate after discontinuing penicillamine, differentiating it from idiopathic myasthenia.
Area of Science:
- Neurology
- Rheumatology
- Clinical Immunology
Background:
- Penicillamine is a chelating agent used to treat rheumatoid arthritis and Wilson's disease.
- Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disease characterized by fluctuating muscle weakness.
- Penicillamine-associated MG is a rare but recognized complication of penicillamine therapy.
Observation:
- A patient with rheumatoid arthritis developed clinical and electrodiagnostic signs of MG 7 months after starting penicillamine.
- Electromyography, including single-fiber electromyography, showed abnormalities consistent with MG.
- The patient's condition improved significantly after discontinuing penicillamine.
Findings:
- Clinical improvement correlated with improved electrodiagnostic studies.
- Serum antibody titers to acetylcholine receptors decreased.
- Lymphocyte responsiveness to phytohemagglutinin improved after penicillamine withdrawal.
Implications:
- Penicillamine-associated MG appears to be a distinct clinical entity.
- The syndrome is characterized by a favorable prognosis and high remission rate upon drug cessation.
- Early recognition and discontinuation of penicillamine are crucial for managing this condition.