Chronic primary and secondary pain in children: SAQ

Question 1 (10 marks)

Using the ICD-11 chronic pain classification and the mechanism of central sensitisation, explain how you frame this girl's problem, and justify why her normal investigations are consistent with, rather than contradictory to, her pain. ^[1]

A full-mark answer defines chronic pain, places the case in chronic primary pain, names the nociplastic mechanism and central sensitisation, and explains why a normal scan does not refute the pain. ^[2]

Definition and classification (3 marks). Chronic pain is defined as pain persisting or recurring for more than three months. Under ICD-11, this girl has chronic primary pain, coded MG30.0: pain in one or more regions for more than three months, associated with significant emotional distress and significant functional disability, that is not better explained by another chronic pain condition. The pain moving between sites, the disability reflected in school absence, and the normal screen together place her squarely in the primary, nociplastic group rather than a secondary category such as secondary musculoskeletal or cancer-related pain. ^[1][2]

The mechanism (3 marks). Chronic primary pain is nociplastic, arising from altered nociceptive function in a structurally intact nervous system. The core mechanism is central sensitisation: after prolonged nociceptive input, the spinal cord and brain become more responsive, the threshold for a stimulus to register as pain drops, and mildly unpleasant stimuli become painful. This is a real biological change in how the nervous system processes signals, not a psychological invention, and it explains why the pain is widespread, fluctuating and migrating. ^[1]

Why the normal investigations are consistent (2 marks). Nociplastic pain is generated by altered nervous-system function without ongoing tissue damage, so a normal magnetic resonance image and normal blood tests are exactly what is expected. The error is to read a normal scan as evidence the pain is not real; the correct reframe is that the tests exclude dangerous disease and confirm that the problem is a sensitised nervous system that can be retrained. ^[7]

The fear-avoidance cycle (2 marks). The withdrawal from sport, the broken sleep and the school avoidance describe the behavioural counterpart: the child interprets pain as damage, fears movement, avoids activity, becomes deconditioned, and hurts more when she does move, which confirms the belief that movement is dangerous. Naming this cycle is what makes a graded reactivation plan credible to the family. ^[7]