Background: As the COVID-19 pandemic reached its peak, it became unavoidable that patients with other risk factors for severe pulmonary impairment (such as neuromuscular illnesses) would become afflicted. While the subject of myasthenic crisis secondary to COVID-19 pneumonia represents an interesting topic in the literature, we could not find consistent data that include, as a novel therapeutic approach, both intravenous immunoglobulin and plasma exchange therapy for the treatment of these two concurrent diseases. Case summary: A 69-year-old man with known seropositive generalized myasthenia gravis, hypertension, ischaemic heart disease, NYHA class II-III heart failure, cerebrovascular disease, and recurrent urinary tract infections, was admitted to the ICU for mixed acute respiratory failure, elevated serum lactate and liver function enzymes, and severe thrombocytopenia. A SARS-CoV-2 PCR test was positive, despite a previous COVID-19 pneumonia episode, 10 months prior to the current one. The patient had a recent ICU admission for a myasthenic crisis, which required non-invasive mechanical ventilation and intravenous immunoglobulin therapy. He received supportive therapy, as well as etiological (intravenous remdesivir, plasmapheresis and intravenous dexamethasone). Fifteen days after admission, the patient was transferred to the neurological ward, whence he left 20 days later, with no apparent sequelae. Conclusions: Subsequent intravenous immunoglobulins and plasma exchange therapy appear to be effective and safe in patients with simultaneous acute myasthenic episode and COVID-19 pneumonia.