Imaging the neural correlates of neuropathic pain and pleasurable relief associated with inherited erythromelalgia in a single subject with quantitative arterial spin labelling

We identified a patient with severe inherited erythromelalgia secondary to an L858F mutation in the voltage-gated sodium channel Nav1.7. The patient reported severe ongoing foot pain, which was exquisitely sensitive to limb cooling. We confirmed this heat hypersensitivity using quantitative sensory testing. Additionally, we employed a novel perfusion imaging technique in a simple block design to assess her baseline erythromelalgia pain vs cooling relief. Robust activations of key pain, pain-affect, and reward-related centres were observed. This combined approach allowed us to confirm the presence of a temperature-sensitive channelopathy of peripheral neurons and to investigate the neural correlates of tonic neuropathic pain and relief in a single subject.