Exacerbation of myasthenia gravis after zoledronic acid and denosumab: a novel clinical observation with therapeutic implications

Patients affected by myasthenia gravis undergoing long-term corticosteroid therapy have an increased risk of osteoporosis and fragility fractures, frequently requiring antiresorptive treatment. Although bisphosphonates and denosumab are generally well tolerated, rare cases of onset or worsening of myasthenic symptoms following bisphosphonate therapy have been reported, while no cases associated with denosumab have been described to date. We report the case of a 78-year-old woman with long-standing, stable myasthenia gravis who developed a significant exacerbation of myasthenic symptoms following intravenous infusion of zoledronic acid and, subsequently, after a single administration of denosumab. In both instances, a temporary increase in corticosteroid therapy was required. Following these events, antiresorptive agents were discontinued, and supplementation with cholecalciferol was maintained. To our knowledge, this represents the first reported case of exacerbation of myasthenic symptoms following denosumab administration.