Relapsing and Immune-Responsive Paroxysmal Jaw Clonus With Blepharospasm and Sialorrhea Associated With D2R Autoantibodies

OBJECTIVES: To extend the symptomatic spectrum of acute neurologic syndrome associated with dopamine-2 receptor (D2R) antibodies. METHODS: A 13-year-old adolescent boy was admitted to the Neurology Department with abnormal jaw movements. The initial evaluation included laboratory examinations of blood, chest radiography, brain MRI, EEG, and neuropsychologic tests. Serum and CSF samples were collected for immunologic studies. The clinical outcome of the patient was followed up for 18 months after the first hospitalization. RESULTS: Paroxysmal jaw clonus, blepharospasm, and sialorrhea were observed in the patient with a history of Tourette syndrome and obsessive–compulsive disease and with an acute neurologic syndrome associated with D2R antibodies. The symptoms responded to IV methylprednisolone (IVMP), relapsed twice during prednisone reduction, and, finally, improved after the combined treatment of IVMP and IV immunoglobulin. DISCUSSION: Recognizing paroxysmal jaw clonus (possibly with blepharospasm and sialorrhea) and considering the relationship between these episodes and D2R antibodies will be helpful in the early diagnosis and treatment of immune neurologic syndromes.