| Electrodiagnostic Studies of D-Penicillamine Associated Myasthenia Gravis in a Pediatric Patient with Wilson’s Disease: A Case Report |
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Received: 30 January 2018 • Accepted: 2 April 2018 |
| Abstract |
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A 15-year-old girl with Wilson’s disease complained of progressive proximal muscle weakness and difficulty with mastication aggravated by prolonged chewing with a diurnal variation for 3 weeks. Repetitive nerve stimulation using supramaximal stimuli revealed post-synaptic disorder and the needle electromyographic study showed the myopathic motor unit action potentials without any abnormal spontaneous activity in all sampled upper and lower limb muscles and the masseter, consistent with the suspicion of penicillamine-induced myasthenia gravis (PMG). The patient showed clinical improvement after discontinuation of D-penicillamine. Because of its favorable prognosis and curable treatment option, when proximal weakness with diurnal variation occurs after long-term administration of D-penicillamine, PMG should be suspected. In the electromyography laboratory, PMG should be distinguished from myositis and other neuromuscular diseases by performing the repetitive nerve stimulation test of proximal muscle recording. The discontinuation of penicillamine and administration of anticholinesterase are promptly considered to lead to better outcomes in those populations. |
| Key Words:
penicillamine, myasthenia gravis, neuromuscular junction diseases |
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