Delayed diagnosis of myasthenia gravis caused by concurrent anxiety symptoms

Myasthenia gravis (MG) is the most frequent autoimmune disorder of the neuromuscular junction. Patients with MG often have concomitant psychiatric complications, with high prevalence rate of depression and anxiety. These disturbances may sometimes delay the diagnosis of MG. Moreover, the prescription of drugs used in anxiety disorder, such as benzodiazepines, interferes with the correct function of the neuromuscular junction, and may determine worsening of the symptoms.

In this paper, we report the case of a 54-year-old woman with bulbar onset of MG and without circadian fluctuations who, during the COVID pandemic and partly consequent to it, was initially diagnosed with anxiety disorder, and treated with psychiatric drugs that eventually worsened the picture and led her to the emergency room.

Our case is an example of how a concurrent anxiety disorder may mask and postpone the diagnosis of MG in patients without a clear modification of symptoms during the day. Misdiagnosing MG with anxiety disorder may have severe consequences.