Long-term alteration of pain sensitivity in school-aged children with early pain experiences

Abstract

While animal studies suggest that neonatal pain experiences induce long-term alterations in pain sensitivity, no such data exist in humans. Changes in pain sensitivity in school-aged children (9-14 years) who were born preterm or fullterm, had been hospitalized for a prolonged period of time after birth and had undergone repeated painful procedures while being treated in a Neonatal Intensive Care Unit (NICU) were determined. A retrospective cohort study of 19 preterm (<or=31 weeks gestational age) and 20 fullterm children (>or=37 weeks gestational age) treated at least 3 days in a NICU at a University Hospital and 20 fullterm control children without NICU experience was performed. Perceptual sensitization to tonic heat and repetitive mechanical stimuli as well as heat pain and mechanical pain thresholds were obtained at the thenar and a trigeminal site. Length of hospitalization and NICU treatment was significantly higher in preterm than fullterm children. Nonetheless, both preterm and fullterm children with NICU experience showed greater perceptual sensitization to tonic heat and elevated heat pain thresholds at both sites. Mechanical pain threshold and perceptual sensitization did not differ between groups. Consistent with findings in animals, repeated pain experiences during the neonatal period were associated with alterations in thermal pain responsivity in school-aged preterm and fullterm children that was characterized by enhanced perceptual sensitization to prolonged painful stimulation and hypoalgesia to brief heat pain stimuli. Our findings suggest that repeated pain experiences in neonates may induce activity-induced changes in the functioning of pain pathways that persist well beyond infancy.

Sex-related long-term behavioral and hippocampal cellular alterations after nociceptive stimulation throughout postnatal development in rats

“…The current findings of reduced thermal response produced by intraplantar application of CFA in all ages (P1, P8 or P21) suggest that throughout ontogeny differences in the behavioral repertoire might be subtle. Based on the literature from human (Hermann et al, 2006) and animal models (Benatti et al, 2009;LaPrairie and Murphy, 2007), one would expect that the earlier the noxious stimulation the more pronounced the changes in later nociception. The fact that P21 rats also showed high nociception thresholds may indicate that the critical period for establishment of the nociceptive circuitry is susceptible to additional factors not, as yet, well understood.…”

“…Recent clinical follow up studies have demonstrated that in adulthood, former preterm children display altered pain threshold (Hermann et al, 2006;Hohmeister et al, 2010;Walker et al, 2009) and decreased modulatory pain mechanisms (Goffaux et al, 2008). Ten year-old former preterm infants rate medical-related pain pictures as more intense that other pain pictures, indicating that they may have more pain memories than age-matched full term infants (Grunau et al, 1998).…”

Pain in preterm infants: Effects of sex, gestational age, and neonatal illness severity.

“…One study was a prospective-longitudinal design that examined the association between clinical pain in the NICU and the later pain reactivity of the children at 6 months of age (Gibbins et al, 2008b). pain history and later pain, which was assessed in a laboratory setting in children between 7 and 14 years of age (Hermann et al, 2006;Goffaux et al, 2008;Hohmeister et al, 2009). …”

Safety of opioid patch initiation in Australian residential aged care

“…In clinical studies, neonatal intensive care and surgery have been associated with: alterations in pain-related behaviour 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 ).…”