Abstract

We describe a 48-year-old man with history of chronic pain radiating from the right oral cavity to the occipital region with comorbid depression. Although he was receiving drugs such as sodium valproate and maprotiline for comorbid depression, they had little effect and his decreased concentration and motivation became protracted, making him unable to work. Electroencephalography findings suggested a mild consciousness disorder. Blood test indicated serum ammonia levels were abnormally elevated. After valproate administration was gradually tapered off, the symptoms of decreased motivation and cognitive inhibition rapidly improved and he became more active. Although his moderate pain persisted, he no longer complained of pain. Finally, he succeeded to return to work. The central nervous system depression due to valproate and hyperammonemia may have decreased his activity levels and exacerbated his pain. The objective of chronic pain therapy should be to help improve the patient’s quality of life in addition to alleviating pain, and attention must be paid to the possibility that one adverse drug effect may exacerbate pain due to a consciousness disorder and decreased one’s activity levels. This could be a valuable case report, because there are little reports about a relationship between chronic pain and consciousness disorder.

Key words: Chronic oral pain, consciousness disorder, valproate, hyperammonemia