Neuropathic pain in children: Viva

Branch 1: Defining and grading the pain

The candidate should open by defining neuropathic pain as pain caused by a lesion or disease of the somatosensory nervous system, distinct from nociceptive pain (actual or threatened tissue damage) and nociplastic pain (altered nociception without a clear lesion). The distinction matters because neuropathic pain responds poorly to opioids and non-steroidal anti-inflammatory drugs and better to drugs that quieten nerve firing, such as gabapentinoids and tricyclic antidepressants, and because recognising the mechanism unlocks the rehabilitation and function-focused plan. The candidate should then apply the NeuPSIG grading system: this girl's pain has a plausible neuroanatomic distribution in the affected limb and a plausible injury, so it is at least possible neuropathic pain, and the clinical signs of allodynia, hyperalgesia, and sensory change support that grade. ^[1]

If the examiner presses on the grading steps, the candidate should name all three levels: possible neuropathic pain with a neuroanatomic distribution and a relevant history; probable neuropathic pain when a confirmatory test, such as neurophysiology or imaging, demonstrates the lesion; and confirmed neuropathic pain when a diagnostic test shows that the lesion explains the pain. The candidate should note that most paediatric consultations end at probable, and that this is sufficient to begin the neuropathic plan. A strong candidate adds that the bedside signatures are allodynia, hyperalgesia, and sensory loss, and that a child who flinches from the bedclothes is showing allodynia through behaviour. ^[1]