871 - A Case of Managing Chronically Acute-on-Chronic Pain: SCN9A Paroxysmal Extreme Pain Disorder in a Medically Complex Patient

Case Diagnosis: Paroxysmal extreme pain disorder


Case Description: A 23-year-old female presented to pain clinic with chronic pain since childhood. Her pain began as a young child and could not be attributed to trauma. She was taken to pediatric specialists including pediatric psychiatrists, pediatric neurologists, and pediatric rheumatologists. The only positive finding was juvenile idiopathic arthritis, which when treated did not alleviate the pain. She failed multiple pain medication regimens including adjunctive therapies like acupuncture, vagal nerve stimulator, and physical therapy. She was considered a medical anomaly and used opiates to control her pain. Her pain has stabilized for 8 years on high doses of gabapentin, liquid hydrocodone-acetaminophen, and 90 milliequivalents of morphine. After genetic testing, an SCN9A gene mutation was found and the patient is now scheduled to see a tertiary hospital for further specialized care. The pain specialist is now considering a trial of sodium channel blockers.



Discussions: Pain is of great concern in modern medicine and is carried by various pathways. One pathway involves the opening and closing of ion channels in the nerve conduction cascade which results in neuropathic pain. The SCN9A gene encodes a sodium channel that contributes to this mechanism when a gain-of-function mutation ensues. The SCN9A-mutation syndromes are categorized into erythromelalgia, paroxysmal extreme pain disorder, and small fiber neuropathy. Erythromelalgia is classified by bilateral intense burning pain in the feet, while small fiber neuropathy presents in a stocking and glove distribution. Paroxysmal extreme pain disorder, our patient’s diagnosis, causes episodes of intense pain brought on by sensory stimuli. These episodes begin focally and spread distally, lasting from seconds to hours.


Conclusions: In pediatric patients with severe uncontrolled pain, consider congenital pain disorders such as SCN9A mutation. SCN9A mutations lead to neuropathic syndromes that add complexity to pain management and may not respond well to traditional pain control measures.