There have been reported cases of patients with both myasthenia gravis and Parkinson's disease, and rarely myasthenia co-presenting with GAD-65 autoantibodies. However, this is the first reported case of a patient with myasthenia, GAD-65 associated ataxia, and parkinsonism. 

A 70-year-old woman was hospitalized in July 2018 after presenting with progressive generalized weakness and slurred speech over 2-3 months. ROS: decreased appetite, cough, dyspnea, and history of falls; PMH: rheumatoid arthritis, hypothyroidism, and breast cancer in remission.

During hospitalization, she became unresponsive, suffered cardiorespiratory arrest, and was intubated. Cardiac catheterization revealed Takotsubo cardiomyopathy. Ventilator  weaning was difficult and she underwent tracheostomy, and placement of a percutaneous endoscopic gastrostomy (PEG) tube.

Chest imaging showed pneumonia, but no evidence for thymoma.

She was treated for a myasthenia gravis (MG) crisis with IVIG and subsequently, plasmapheresis. Maintenance MG treatment included prednisone and monthly IVIG. She gradually recovered and the tracheostomy and PEG were removed. At follow up, Labs revealed acetylcholine receptor antibodies.

She presented to our institution for a second opinion. Exam was significant for dysarthria, right-sided ptosis and mild, fatigable bilateral upper extremity weakness. She had a mild low amplitude rest tremor in the right hand,  bilateral bradykinesia,  left- sidedpostural tremor and dysmetria.  She required mild assistance to stand and a walker to ambulate.

Serologic evaluation for ataxia revealed a GAD-65 antibody titer of >250 IU/mL.

Myasthenia gravis, GAD-65 associated ataxia, and parkinsonism can co-occur. This is the first reported case of these three neurologic syndromes, present in a patient with multisystem autoimmune disease. Phenotypic recognition is essential to diagnose distinct neurologic syndromes that may co-exist, and to individualize therapy.