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10.2 LONG-TERM CONSEQUENCES OF EARLY PAIN
AND INJURY
Significant reorganisation of synaptic connections occurs in the postnatal period. Activity
within sensory pathways is required for normal development, but abnormal or excessive
activity related to pain and injury during the neonatal period may alter normal development
and produce persistent changes in sensitivity that outlast the injury (Fitzgerald & Walker, 2009).
In clinical studies, neonatal intensive care and surgery have been associated with: alterations
in pain‐related behaviour (Grunau et al, 2006 Level IV); enhanced response to future noxious
stimuli (Taddio & Katz, 2005 Level III‐2); increased perioperative analgesic requirements when
subsequent surgery is performed (Peters, Koot, de Boer et al, 2003 Level III‐2); and long‐term
changes in sensory processing (Hermann et al, 2006; Walker et al, 2009 Level III‐2). In laboratory
studies, the degree of long‐term change varies with the type and severity of injury (Fitzgerald &
Walker, 2009). Inflammation, full thickness skin wounds, and skin incision produce prolonged
alterations in sensitivity and in the response to future injury in the absence of any visible
persistent peripheral injury. By contrast, allodynia following nerve injury is less apparent in
early life (Howard et al, 2005; Moss et al, 2007). These findings are of considerable importance
as pain and injury in neonates may have effects on nociceptive processing that differ in
mechanism and duration from that experienced by older children and adults.
Importantly, analgesia at the time of the initial painful stimulus may modulate long‐term
effects. Male neonates circumcised without analgesia showed an increased behavioural pain
response to immunisation several months later, but this was reduced if local anaesthetic was
used prior to the procedure (Taddio et al, 1995 Level III‐2). Infants who had undergone surgery in
the neonatal period with perioperative morphine did not show any increase in later response
to immunisation when compared with infants without significant previous pain experience
(Peters, Koot, de Boer et al, 2003 Level III‐2). Further research is required to determine the most
developmentally appropriate and effective analgesic regimen for modulating the effects of
early pain and injury.
Key messages
The following tick boxes represent conclusions based on clinical experience and expert
CHAPTER 10 opinion.
Following birth, even the most premature neonate responds to nociceptive stimuli (U).
In early development more generalised reflex nociceptive responses occur in response to
lower intensity stimuli (U).
Due to the increased plasticity of the developing nervous system, pain and injury in early
life may have adverse long‐term consequences (U).
10.3 PAEDIATRIC PAIN ASSESSMENT
Pain assessment is a prerequisite to optimal pain management in children and should involve
a clinical interview with the child and/or their parent/carer, physical assessment and use of an
age‐ and context‐appropriate pain intensity measurement tool (Howard et al, 2008). However,
pain in hospitalised children is often assessed infrequently (Johnston et al, 2007; Twycross, 2007;
Taylor et al, 2008). Improvements in pain management and in patient, parent and staff
satisfaction have been associated with regular assessment and measurement of pain (Treadwell
336 Acute Pain Management: Scientific Evidence
