A possible case of complex regional pain syndrome in the orofacial region

To present a case of complex regional pain syndrome (CRPS) type II with sympathetic dysfunction and trophic changes in the orofacial region, which was partially responsive to intravenous ketamine.

The patient was a 68-year-old man who suffered from inveterate pain with trophic changes of the right face and tongue and vasomotor dysfunction on the right side of the face after ipsilateral trigeminal nerve block. Allodynia and hyperalgesia were observed on the affected side of the face. Pain initially improved after sympathetic nerve block, but similar pain returned that was unresponsive to the same procedure. Repeated intravenous administration of low-dose ketamine preceded by intravenous midazolam alleviated the pain, but trophic changes of the tongue persisted.

CRPS in the orofacial region has not been clearly defined and has been infrequently documented. Clinical findings in this patient met the criteria of the International Association for the Study of Pain's and Harden's diagnostic criteria for CRPS. The reason for gradual pain relief after induction of intravenous ketamine therapy was unclear, but the fact that only ketamine and not other various pain medicines or procedures alleviated the pain is important to note.

Distinct cases of CRPS involving the orofacial region are rare. Thorough observations and documentation of signs and symptoms may lead to future standardization of diagnostic criteria and treatment strategies for this disorder.