Disclosures: Thomas Chai, MD: No financial relationships or conflicts of interest

Case Description: The patient reported poor pain control, despite the use of opioids, anti-inflammatories, anticonvulsants, antidepressants, muscle relaxants, and others. She had limited response to local steroid injections, intense physical therapy, and hyperbaric oxygen therapy. It was thought then that the patient may be an appropriate candidate for intravenous ketamine. The patient then underwent, at biweekly intervals, 6 sessions of ketamine infusion at 0.5 mg/kg (25 mg for this patient), over one hour.

Setting: Tertiary care cancer hospital

Patient: 53 year-old female with oncologic history of metastatic left breast cancer, status post multimodality treatment, to include radiation therapy to the left chest wall and axilla, with subsequent development of painful radiation-induced brachial plexopathy of the left upper limb. Assessment/

Results: Immediately after each ketamine infusion, the patient reported resolution of her severe left upper limb pain. This relief lasted about 2 weeks per session, with minimal psychotomimetic side effects. The patient was then recommended to proceed with nerve transfer surgery for both sensorimotor and functional improvement of the left upper limb.

Discussion: Ketamine is an anesthetic induction agent, and when used at sub-anesthetic doses, has been found to have utility in treating both chronic pain states and depressive disorders. Ketamine has been used to treat cancer pain, complex regional pain syndrome, central pain from spinal cord injury, phantom limb pain, fibromyalgia, and other conditions. One likely explanation for its analgesic effect is through the blockade of the N-methyl-D-aspartate (NMDA) receptors in the central nervous system and reversal of central sensitization. A wide range of ketamine infusion protocols and dosing regimens exists. The author’s institution suggests a ketamine dose of 0.5 mg/kg, with a range of 0.1-1 mg/kg, given over one hour.

Conclusion: Ketamine infusion should be considered for refractory neuropathic pain states, such as unremitting upper limb pain due to radiation-induced brachial plexopathy.

Level of Evidence: Level V

« Back to AAPM&R Annual Assembly 2020

PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/refractory-painful-brachial-plexopathy-due-to-radiation-therapy-relieved-with-serial-intravenous-ketamine-infusions-a-case-report/