Risk Factors Associated with the Progression from Acute to Chronic Neuropathic Pain after Burn-Related Injuries

Background Pain, unrelated to the initial thermal trauma itself, can result after burn injury and prolong the recovery/rehabilitation phase of the patient's care. This pain, after discharge from the burn unit, may be acute and self-limiting or chronic and contribute to long-term patient morbidity. The purposes of this study were to compare burn patients who had, after discharge from the burn unit, only acute pain with burn patients who developed chronic, neuropathic pain (CNP) and to determine risks factors for progression from acute to chronic pain in the setting of a burn center. Methods A single-center, retrospective chart review of patients admitted to the adult burn center was performed from January 1, 2014, to January 1, 2019. Patients included were older than 15 years, sustained a burn injury, and admitted to the burn unit. Chronic pain was defined as pain lasting greater than 6 months after discharge from the burn unit. Pain descriptors included shooting, stabbing, sharp, burning, tingling, numbness, throbbing, pruritus, intermittent, and/or continuous dysesthetic sensations after the burn. Patients were excluded if they had preexisting neuropathic pain due to an underlying medical illness or previous surgery. Results During a 5-year period, of the 1880 admissions to the burn unit, 143 burn patients developed post-initial-onset pain as a direct result of their burn. Of the 143 patients with acute pain, pain resolved in 30 patients, whereas pain progressed to CNP in 113 patients (79%). Patient follow-up was a median (interquartile range [IQR]) of 26.5 (10-45) months. Patients whose pain progressed to CNP had significantly greater percent total body surface area burns (median [IQR], 6 [3-25] vs 3 [1-10]; P = 0.032), had more full-thickness burns (66/113 [58%] vs 8/30 [27%] patients, P = 0.004), had surgery (85/113 [75%] vs 16/30 [53%] patients, P = 0.042), had more surgical procedures (median [IQR], 2 [1-6] vs 1 [0-3], P = 0.002), and developed more complications (32/113 [28%] vs 2/30 [7%] patients, P = 0.014) compared with those with acute neuropathic pain, respectively. Conclusions Burn patients who progressed from having acute to CNP had significantly greater percent total body surface area burns, had more full-thickness burns, had surgery, had more surgical procedures, and developed more complications compared with burn patients with only acute pain.