Treatment of severe pain in a patient with complex regional pain syndrome undergoing dental treatment under general anesthesia: A case report.

Complex regional pain syndrome (CRPS) is rare, characterized by pain from diverse causes, and presents as extreme pain even with minor irritation. General anesthesia may be required for dental treatment because the pain may not be controlled with local anesthesia. However, treatment under general anesthesia is also challenging. A 38-year-old woman with CRPS arrived for outpatient dental treatment under general anesthesia. At the fourth general anesthesia induction, she experienced severe pain resulting from her right toe touching the dental chair. Anesthesia was induced to calm her and continue the treatment. After 55 minutes of general anesthesia, the patient still complained of extreme toe pain. Subsequently, two administrations for intravenous sedation were performed, and discharge was possible in the recovery room approximately 5 h after the pain onset. The pain was not located at the dental treatment site. Although the major factor causing pain relief was unknown, ketamine may have played a role.