Typical and atypical clinical presentations

Myasthenia gravis (MG) is the prototypical disorder of the neuromuscular junction. The clinical hallmarks of MG are fatigability and fluctuating voluntary muscle weakness. Although MG can potentially affect any muscle, some muscle groups are involved preferentially and an important clinical distinction can be made between the disease localized exclusively to the extraocular muscles and the disease affecting other muscle groups, called “generalized”, with relevant therapeutic and prognostic implications. The clinician should be familiar with both common and uncommon patterns of weakness associated with MG and actively search for suggestive anamnestic cues when this disease is suspected. This chapter will focus on the different clinical presentations of MG, encompassing both the detailed clinical complaints and the anamnestic aspects, with a focus on the specific muscular distribution, and the clinical features associated with myasthenic crisis. Lastly, the most described atypical presentations and their differential diagnostic work-up will be reviewed.