Intravenous Immunoglobulins Efficacy in a Case of ALS with Myasthenic Symptoms

Abstract

Background and aims: Myasthenia gravis (MG) is a neuromuscular junction disease, for which the most specific test is an increase in anti-acetylcholine receptor antibodies (anti-ACHR-Abs) titre. Myasthenic symptoms are rarely detected in patients with amyotrophic lateral sclerosis (ALS). We report the intriguing case of a sporadic ALS patient with myasthenic features at onset and clinical improvement in strength and disease severity after longterm immunomodulation therapies. Methods: A 54-year-old woman came to our observation for a fluctuating bulbar and spinal muscular weakness. Serum dosages of acetylcholine receptor (AChR) and muscle-specific kinase (Musk) antibodies were normal. Considering the clinical and instrumental features indicative of a disorder of the neuromuscular junction, we began a treatment with pyridostigmine (180mg/day), prednisone (25mg/day) and azathioprine (100mg/day), obtaining a clinical improvement in fluctuations of muscular strength for one year. Afterward, we observed a generalized, progressive worsening of weakness. Thus, she was treated with intravenous immunoglobulins. Results: After the first cycle, the patient was able to eat and walk autonomously also for long distances and, even more, she was autonomous in manipulating objects and getting dressed. However, this improvement lasted about two months and, subsequently, she showed a decrease of strength in the same muscle groups involved at onset. Therefore, we repeated cyclically this treatment every two months for one year obtaining, after each IVIg course, mild improvement of strength Conclusion: The efficacy of such immunomodulation treatment in our unusual case leads to rethink the role of immune response in ALS.