Ketamine for Complex Regional Pain Syndrome (CRPS)

We move beyond depression and anesthesia to examine ketamine's role in fighting one of the most severe types of chronic pain imaginable: Complex Regional Pain Syndrome (CRPS). This condition is marked by wildly disproportionate and persistent pain , exemplified by the case of a 15-year-old athlete whose simple hand fracture healed, but whose nervous system got stuck in a pathological pain loop. The core problem in CRPS is central sensitization—the brain and spinal cord jamming the "volume knob" for pain on maximum, where a light touch (allodynia) is interpreted as excruciating. Traditional treatments fail because the problem is upstream, residing in the central nervous system (CNS). Specialists employed a clever, multimodal strategy to finally break this refractory pain cycle: Gabapentin: To calm general static in the nervous system. Continuous Nerve Block: A regional anesthetic to temporarily silence all incoming peripheral pain signals from the arm. Continuous Ketamine Infusion: The NMDA receptor antagonist was the core component, performing a "software reboot" on the CNS. Ketamine acts as a master switch, physically blocking the NMDA receptor that powers the central sensitization system, thereby interrupting the vicious wind-up cycle. The results were dramatic: pain, which was agonizing, dropped from 7/10 to 2/10 within 24 hours, resolving completely in 48 hours. Allodynia resolved, enabling the essential physiotherapy needed for long-term recovery. This case report is a powerful demonstration of ketamine's versatility, showing it can act not just as a painkiller, but as a system reset for neurological conditions rooted in faulty learning. Reference: Medikondu, H., Davit, A., & Visoiu, M. (2025). Effective Adolescent Hand CRPS Type 1 Treatment Using Ketamine, Gabapentin, and Supraclavicular Nerve Block Catheter. Preprints.org. https://doi.org/10.20944/preprints202511.0755.v1