2017 年 34 巻 3 号 p. 160-162
Autoimmune encephalopathies are clinically and immunologically heterogeneous disorders. Many different types of autoimmune encephalopathy have been discovered, and most common type may be Hashimoto encephalopathy in it. In clinical situations, we often recognize that patients with autoimmune encephalopathy are often misdiagnosed as exhibiting functional psychogenic movement, conversion, or somatoform disorders. We clinically analyzed 63 patients with autoimmune encephalopathy. Two–thirds of patients showed motor disturbance mostly with give–way weakness. About 70% of patients showed sensory abnormalities such as strong pain, deep muscle pain, dysesthesia, paresthesia, or fast neurologic pain. Most pain was distributed in manner that was not explainable anatomically. 27% of patients exhibited involuntary movements such as tremor entrainment, dystonia, or coarse involuntary movement. We observed memory loss, PNES (psychogenic non–epileptic seizure), dissociative amnesia, hyperventilation, opsoclonus, epilepsy, or autonomic symptoms amongst our patients. Although give–way weakness, anatomically unexplainable pain, and strange involuntary movements were thought to be psychogenic, the presence of one of these three symptoms was indicative of autoimmune encephalopathy. As autoimmune encephalitis exhibits diffuse involvement with the whole brain, these symptoms were entirely understandable. Except for the presence of organic disease, most patients were classified into somatoform disorders or functional movement disorders. Without first excluding autoimmune encephalopathy, physicians should not diagnose somatoform disorders.