[Acute pain in children and its treatment]

Pain in paediatrics has long been underestimated. The numerous scientific studies carried out during the last decade show that its existence can no longer be doubted: in fact, pain already exists during the neonatal period, and probably throughout the last trimester of gestation as well. Pain pathways mature during the embryonic period and peripheral receptors develop between the 7th and 20th week. A-delta and C fibers, as well as spinal roots and nerves, are completely differentiated before the end of the second month. The development of specific neurotransmitters and thalamic and cortical dendritic branching occurs later on; it is well enough developed to allow perception of painful stimuli (slow or protopathic component) from the beginning of the foetal period onwards. The discriminative rapid component develops in parallel to myelinisation, and the psycho-affective component, which requires a long and complex learning process, will not be fully operative until the end of puberty. Assessing pain, already a difficult task in the adult, is all the more so in children because of lesser verbal communicative capabilities, difficulty in handling abstract concepts, lack of experience of painful stimuli to make comparisons, and ignorance of their body image. In the very young child, diagnosing pain relies on suggestive circumstances, and an altered behaviour, knowing that no one symptom in pathognomonic. As the child grows up, methods for self-assessment of pain become usable, such as coloured scales and simplified verbal scales. However, behavioural tests remain the mainstay until the prepubertal period. The treatment of acute pain requires a reasoned approach which takes into account the state of the child, that of the aetiological investigations, the likely course of the lesions, as well as the patient's analgesic requirements. Therapeutic means do not differ from those for adult patients; however, the differences of distribution of body water, the small possibilities of linking with plasma proteins, and limited conjugation with glucuronate must be taken into account, especially during the first months of life. Local and regional anaesthetic block techniques are of great interest in elective and emergency surgery, as well as in trauma: they can provide complete pain relief, mostly without having any effect on the patient's physiological state (haemodynamics and consciousness). Peripherally acting analgesic agents, which are well supported on the whole, as well as co-analgesics, have a great part to play, although there are less drugs available than for adults. The most useful ones are paracetamol, followed by the salicylates, propionic acid derivatives and non steroid anti-inflammatory drugs.(ABSTRACT TRUNCATED AT 400 WORDS)