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D-penicillamine-induced myositis in rheumatoid arthritis
1Department of Physical Medicine and Rheumatology, Middelheim Hospital, Antwerp, Belgium.
Abstract:
D-penicillamine, an agent still used in the treatment of rheumatoid arthritis (RA) may produce inflammatory myopathy or myositis. Some reported cases are documented with muscle biopsy. We report a 34-year old female, receiving the drug for more than 4 years, who consulted us with recently developed proximal muscle pain and weakness. EMG-findings were typical for inflammatory muscle disease; muscle enzymes remained normal. D-penicillamine was stopped and she was started on prednisolone with rapid improvement. The EMG-findings, with follow-up within three months, proved to be a good diagnostic tool, in the absence of laboratory muscle enzymes abnormalities.
Insights
D-penicillamine can cause inflammatory myopathy in rheumatoid arthritis patients. Electromyography (EMG) is a valuable diagnostic tool for this condition, even when muscle enzymes are normal.
Area of Science:
- Rheumatology
- Neurology
- Toxicology
Background:
- D-penicillamine is a medication used for rheumatoid arthritis (RA).
- Drug-induced myopathy is a known adverse effect of some medications.
- Inflammatory myopathy can present with muscle pain and weakness.
Observation:
- A 34-year-old female on long-term D-penicillamine therapy developed proximal muscle pain and weakness.
- Electromyography (EMG) revealed findings consistent with inflammatory muscle disease.
- Serum muscle enzyme levels were normal in this patient.
Findings:
- Discontinuation of D-penicillamine and initiation of prednisolone led to rapid clinical improvement.
- EMG proved to be a sensitive diagnostic tool for D-penicillamine-induced myopathy.
- This case highlights the utility of EMG in diagnosing inflammatory myopathy when muscle enzymes are unremarkable.
Implications:
- Clinicians should consider D-penicillamine-induced myopathy in RA patients presenting with unexplained muscle symptoms.
- EMG is a crucial diagnostic modality for identifying drug-induced inflammatory myopathy, especially with normal laboratory markers.
- Early diagnosis and management can lead to favorable outcomes in patients with D-penicillamine-induced myopathy.