Prolonged Effect of Botulinum Toxin- A Treatment in Patients with Myasthenia Gravis

Purpose: To report the unexpectedly prolonged effect of botulinum toxin A (BTX) injection in patients with myasthenia gravis. Methods: Retrospective review of presenting history, clinical findings and treatment of two cases. Results: Two patients with myasthenia gravis underwent a single BTX injections for gustatory epiphora (case 1) and hemifacial spasm (case 2). The effect of the treatment lasted 18 months and at least 8 months respectively. Conclusion: We report the prolonged effect of BTX in two patients with myasthenia gravis. To our knowledge, the prolonged and distant effect of BTX in myasthenia gravis has not been specifically addressed in the literature. We postulate that this prolonged effect may be due to the presence of autoantibodies in patients with myasthenia gravis.