Myasthenia gravis is characterised by fluctuating weakness and muscles that tire easily. An acute increase in symptoms can be life-threatening because of swallowing difficulties or respiratory failure. Myasthenia gravis is an autoimmune disorder in which the body's own antibodies block the transmission of nerve impulses to muscles and damage the neuromuscular junction (where the nerve meets the muscle). With optimal treatment, including thymectomy, corticosteroids, immunosuppressive drugs and plasma exchange, most people with myasthenia gravis go into remission or improve but these treatments can cause many adverse events. Intravenous immunoglobulin (IvIg), (antibodies purified from human blood), is effective in other autoimmune diseases. The objective of this review was to examine the efficacy of intravenous immunoglobulin for treating acute exacerbations or for chronic long-term, persistent myasthenia. We identified six randomised controlled trials, all of which investigated short-term benefit. Adverse events due to intravenous immunoglobulin were observed in all trials. They were moderate (fever, nausea, headache), self-limiting and less severe than with plasma exchange.
For treating exacerbations, one randomised controlled trial of intravenous immunoglobulin versus placebo demonstrated the efficacy of intravenous immunoglobulin for treating exacerbations of myasthenia gravis. Another trial showed no significant difference between intravenous immunoglobulin and plasma exchange. According to another trial, the effect of 1 g/kg of intravenous immunoglobulin on two consecutive days was not significantly better than a single 1 g/kg dose. For moderate or severe myasthenia gravis there is no evidence from randomised controlled trials nor from other trials to determine whether intravenous immunoglobulin improves function or reduces the need for steroids. There is insufficient evidence to favour intravenous immunoglobulin over corticosteroids in moderate exacerbations.