Diagnostic flowchart: All patients with suspected MG should undergo testing for anti-AChR antibodies. The detection of serum anti-AChR antibodies in a patient with the appropriate clinical presentation essentially confirms the diagnosis of MG, and obviates the need for further testing. Anti-MUSK testing is usually done on patients with generalised MG who are negative for AChR antibodies, but consideration might be given to initial anti-MUSK testing (at the time of anti-AChR testing) in the presence of severe bulbar and facial weakness with marked muscle atrophy. The repetitive nerve stimulation and SFEMG tests are usually done while the results of the antibody tests are awaited; even if electrophysiological tests are positive, the results of antibody tests are still useful to identify patients with particular subsets of MG. The edrophonium and ice-pack tests are used in selected patients to make a bedside confirmation of a suspected diagnosis of MG (indicated by a dashed outline), but more objective confirmation is desirable (anti-AChR antibodies, repetitive nerve stimulation, or SFEMG). | AChR=acetylcholine receptor. MG=myasthenia gravis. MUSK=muscle-specific receptor tyrosine kinase. SFEMG=single-fibre electromyography. | Meriggioli, M. N., & Sanders, D. B. (2009). Autoimmune myasthenia gravis: emerging clinical and biological heterogeneity. The Lancet. Neurology, 8(5), 475–490.

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