Neonatal pain: What's age got to do with it?

BACKGROUND: The neurobiology of neonatal pain processing, especially in preterm infants, differs significantly from older infants, children, adolescence, and adults. Research suggests that strong painful procedures or repeated mild procedures may permanently modify individual pain processing. Acute injuries at critical developmental periods are risk factors for persistent altered neurodevelopment. The purpose of this narrative review is to present the seminal and current literature describing the unique physiological aspects of neonatal pain processing. METHODS: Articles describing the structures and physiological processes that influence neonatal pain were identified from electronic databases Medline, PubMed, and CINAHL. RESULTS: The representation of neonatal pain physiology is described in three processes: Local peripheral nervous system processes, referred to as transduction; spinal cord processing, referred to as transmission and modulation; and supraspinal processing and integration or perception of pain. The consequences of undermanaged pain in preterm infants and neonates are discussed. CONCLUSION: Although the process and pain responses in neonates bear some similarity to processes and pain responses in older infants, children, adolescence, and adults; there are some pain processes and responses that are unique to neonates rendering them at risk for inadequate pain treatment. Moreover, exposure to repeated painful stimuli contributes to adverse long-term physiologic and behavioral sequelae. With the emergence of studies showing that painful experiences are capable of rewiring the adult brain, it is imperative that we treat neonatal pain effectively.