AChR and MuSK double positive myasthenia gravis has been rarely reported. Generally, it occurs in children and adults after thymectomy or immunotherapy. Furthermore, in a few patients with bulbar or respiratory involvement, MuSK antibodies might be detected after clinical deterioration. We report a man with a very late onset myasthenia gravis (86-year-old) and the coexistence of both antibodies at the time of the diagnosis. Despite the presence of MuSK antibodies, he manifested no bulbar symptoms and had a favorable clinical outcome. However, side effects related to low dose pyridostigmine were evident. Hence, double positivity can also occur in elderly and in more benign forms of myasthenia gravis. Other cases of AChR and MuSK double positive myasthenia gravis could allow a better definition of this condition.
Keywords: AChR; Double positive; Late onset; MuSK; Myasthenia gravis.
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