Pain Management Via A Subcutaneous Infusion Of Ketamine In A Patient With Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS), which is a syndrome that is defined by pain and sudomotor and/ or vasomotor instability, is usually resistant to conventional treatment. Here, a case involving a 30-year-old male patient with CRPS type I who showed severe intractable right shoulder pain with allodynia and hyperalgesia despite being treated with oral medications, nerve blocks including thoracic sympathetic neurolysis, and spinal cord stimulation is described. The patient frequently visited the emergency room due to severe uncontrollable breakthrough pain. Although a favorable effect was observed in response to intermittent ketamine infusion therapies that were performed on an outpatient basis, acute exacerbation of pain occurred frequently during the night and could not be controlled. Therefore, subcutaneous ketamine infusion therapy using a patient-controlled analgesic system was attempted and found to effectively control acute exacerbation of pain during 6 weeks of infusion without serious complications.