DISORDERS OF INTESTINAL MOTILITY IN THE VERY YOUNG INFANT

The contents of the gut are moved along its length by the coordniated contraction of the smooth muscle coats. The pattern of movement is rel ated to the function of particular regions of the gastrointestnial tra ct and is produced by the motility of the bowel which is a consequence of the integrated action of intrinsic and extrinsic nerves, the smoot hs muscle cells and humoral agents. Motility disorders result in alter ations of motor activity which are clinically significant and interfer e with normal propulsive function. The disorders may affect particular regions of the gut or be diffuse and result from disturbances of diff erent levels of control: end organs, intermediate regulatory pathways and higher centres, with either smooth muscle, nerves or endocrine cel ls being involved. In the young infant such disorders are most usually due to either the state of development of the gut or as the result of developmental dysplasias and result in a number of relatively common disorders such as gastro-oesophageal reflux and Hirschsprung disease a s well as uncommon conditions which include diffuse visceral neuropath ies and myopathies. The very premature infant exhibits disordered moto r activity due to the gestationally dependent state of development of the enteric nervous system and smooth muscle coates and the degree to which the infant has been fed. At the present time the developmental s teps involved and their disturbance resulting in pathology of the moto r apparatus are unknown.