Neuropathic Pain Case Study

Patients with SCI may experience several types of chronic pain, including peripheral and central neuropathic pain. The pain syndromes or disturbing sensations are separated into two broad categories: spontaneous pain (independent of peripheral stimuli, persistent, comes and goes, and can be anything from numbness to burning/cutting like) and peripherally evoked pain (in response to non-noxious or noxious stimuli) (40, 41). Neuropathic pain in SCI can arise from multiple system changes in sensory pathways from dorsal root ganglion (DRG) to cortex. Previous studies have shown in mammals, that injury affecting the axons or soma of sensory neurons, with their soma in the DRG, causes hyperexcitability that can lead to spinal sensitization and neuropathic pain (42, 43, 44, 45). Increasing evidence has also suggested a critical role of the thalamus in the development and maintenance of neuropathic pain. Neuropathic pain has been associated with changes in thalamic anatomy, biochemistry, and perfusion (46, 47, 48). …show more content…
NOS is responsible for synthesizing nitric oxide (NO) and citrulline from arginine. NO acts as an intracellular and intercellular messenger in low concentrations (important for neuronal differentiation, survival, and plasticity) and a cytotoxic molecule at high concentrations, able to contribute to pathological conditions including disorders in the brain, spinal cord injury, and neuropathic pain (50, 51). Interestingly, NO has also been known to act as a retrograde messenger, acting to promote long-term potentiation (LTP (52, 53). I propose that the activated NOS/NO system in SCI by microglia and macrophages induces neuropathic pain through changes in thalamic nuclei and increasing hyperexcitability in