Research

Transverse myelitis (TM) is characterized by inflammation of spinal cord presenting with varying degrees of motor, sensory and autonomic dysfunction below the affected level. In autoimmune variants of TM, an up-regulation of Toll-Like Receptor 4 (TLR4) receptors in the microglial cells results in central sensitization by releasing inflammatory cytokines. We present a case of TM with secondary central pain syndrome refractory to multiple pain medications and immune-modulation therapies, which responded to low dose (3-4.5 mg) Naltrexone. Neuropathic pain is commonly associated with TM and is a major cause of disability in such patients. It is typically treated with multimodal analgesic regimens, antiepileptic or antidepressant medications, opioids, sympathetic blocks, and spinal cord stimulation. Naltrexone is a TLR4 antagonist and therefore diminishes the microglial activation and sensitization process. Moreover, at low doses Naltrexone does not inhibit other opioid receptors in the CNS; thereby allowing endogenous anti-nociceptive pathways involving μ-receptors to continue operating. Low Dose Naltrexone has previously been demonstrated to be helpful in relieving a range of symptoms in refractory fibromyalgia, Complex regional pain syndrome, Crohn’s disease, multiple sclerosis, and systemic sclerosis; but it has never been studied in central pain syndrome due to TM. Hence large scale clinical trials should be piloted on the use of Low Dose Naltrexone in alleviating refractory neuropathic pain in autoimmune TM.