Primary and secondary disorders to gut muscle and nerve.

There have been many recent advances in understanding primary disorders of enteric nerve and muscle. Although not common in clinical practice, most gastroenterologists and surgeons will encounter a few such patients. Management is often difficult but these patients form a fascinating area of practice, and put to the test a clinician's skills. There are also exciting discoveries still waiting to be made in this field. This article focuses on conditions which lead to gut dilatation, or more rarely conditions in which there is no gut dilatation but there is definitive proof of an abnormality of gut nerve or muscle. Disorders of enteric nerves or muscles, or of the extrinsic innervation of the gut, can lead to an acute or chronic gut dilatation. These disorders can be primary or secondary to a generalized disease process outside the gut. These conditions tend to fall into clinically homogeneous syndromes, although within each syndrome the underlying pathologies are heterogeneous. The field of primary abnormalities of the enteric nerve and muscle are only beginning to be explored. Many conditions remain to be discovered, each bringing with them new insights into the mechanisms of normal and abnormal gastrointestinal function.