Neuropathic pain after spinal cord injury is common and often refractory to standard treatments. The capsaicin 8% patch is a Food and Drug Administration-approved treatment of neuropathic pain in postherpetic neuralgia and has demonstrated significant efficacy in human immunodeficiency virus-autonomic neuropathy. The patch defunctionalizes transient receptor potential vanilloid 1 receptors, impairing cutaneous nociceptors for a prolonged period (i.e., 8-12 wks) with no systemic side effects. A retrospective review was conducted on the effects of the patch in two patients with spinal cord injury and neuropathic pain refractory to standard treatments. Two weeks after application, both patients reported complete pain relief. Average onset of relief of 4 days and average duration of relief of 197 days, requiring only one to four applications per year, paralleled findings reported in postherpetic neuralgia and human immunodeficiency virus-autonomic neuropathy trials. Upregulation of capsaicin-sensitive transient receptor potential vanilloid 1 receptors after spinal cord injury has been reported. The capsaicin 8% patch is a promising therapeutic agent for neuropathic pain in spinal cord injury.
CONTEXT/BACKGROUND:A 61-year-old female with cervical stenosis underwent an elective cervical laminectomy with post-op worsening upper extremity weakness. Over the first 3 weeks post-op, she received two separate courses of intravenous steroids. Two days after cessation of steroids, she presented with non-specific symptoms of adrenal insufficiency (AI). Initial formal diagnostic tests of random cortisol level and 250 µg cosyntropin challenge were non-diagnostic; however, symptoms resolved with the initiation of empiric treatment with hydrocortisone. Ten days later, repeat cosyntropin (adrenocortocotropic hormone stimulation) test confirmed the diagnosis of AI. FINDINGS:AI is a potentially life-threatening complication of acute spinal cord injury (ASCI), especially in those receiving steroids acutely. Only three cases have been reported to date of AI occurring in ASCI after steroid treatment. The presenting symptoms can be non-specific (as in this patient) and easily confused with other common sequelae of ASCI such as orthostasis and diffuse weakness. The 250 µg cosyntropin simulation test may not the most sensitive test to diagnose AI in ASCI. CONCLUSION:The non-specific presentations and variability of diagnosis criteria make diagnosis more difficult. One microgram cosyntropin simulation test may be more sensitive than higher dose. Clinicians should be aware that AI can be a potential life-threatening complication of ASCI post-steroid treatment. Prompt diagnosis and treatment can reverse symptoms and minimize mortality.