Differential diagnosis of hallucinations in a patient with myasthenia gravis.

We present the case of a 63-year-old woman with comorbidity of myasthenia gravis and psychosis. Different diagnostic hypotheses based on a review of the literature are discussed. A protracted history of physical spousal abuse, patient symptoms, and results of different investigations allowed us to conclude that the patient had a form of posttraumatic stress disorder with secondary psychotic features. Psychosis due to myasthenia gravis is rarely seen, and it remains unclear what is the pathophysiology, if any, for such an association. The present case highlights the difficulties the physician faces in disentangling psychosis as a potential manifestation of myasthenia gravis itself versus being caused by a medical side effect of treatment, or psychosis due to a distinct co-occurring neurologic or psychiatric condition.