Effective use of oral clonazepam in a child with complex regional pain syndrome

Abstract

A 10-year-old boy with a left-leg joint sprain was referred to our pain clinic. Pain had spread to the entire left lower limb in 2 weeks, and gait-disturbance had appeared. Allodynia was present in the left lower limb, and the temperature in the left toes was lower than in the right toes. A diagnosis of complex regional pain syndrome (CRPS) was made. Because the patient continued screaming even when gently touched, we avoided nerve blocks and started an oral anticonvulsant clonazepam 0.5 mg/day. Four weeks later, at 1.2 mg/day of clonazepam, both allodynia and spontaneous pain had reduced markedly. The dose of clonazepam was reduced by 0.2 mg/day 3 weeks later. Neither allodynia nor pain recurred during the next week without medication. We judged that the patient was cured of CRPS 8 weeks after the first medical examination. We believe that clonazepam may be effective to treat pediatric CRPS.