Gastrointestinal motility and perception disorders re-visited.

The importance of gastrointestinal motility and gut perception in medicine has been long recognized. Physiologically, these key functions ensure normal unperceived feeding and digestion, crucial aspects of health and wellbeing. Conversely, pathophysiological disturbances may produce digestive symptoms, which are common in the general population and may range from the simply annoying to the incapacitating. In fact, major disturbances may lead to malnourishment, metabolic imbalance and general deterioration of the body. Altered normal gut motility may also disrupt gut homeostasis, induce changes in the gut flora and facilitate bacterial translocation from the intestine to other viscera (Fig. 1). Clinical recognition of gastrointestinal motility and perception disorders is largely based on the anatomic localization of their symptomatic expression (1-4). Thus, dysphagia, reflux symptoms and chest pain are normally associated with esophageal or gastroesophageal disturbances. Upper abdominal pain or discomfort, early satiety, nausea and vomiting, and other dyspeptic-like symptoms are usually ascribed to dysfunction of the stomach and/or upper small bowel. Bloating is a somewhat mysterious symptom that may be generated by motor/sensorial disturbances throughout the gastrointestinal tract. Diarrhea and/or constipation usually result from small bowel and/or colonic disorders. Ano-rectal symptoms usually derive from dysfunction of the pelvic floor, distal colon or sphincteric structures. Traditionally, clinical conditions were divided into somatic gastrointestinal motility disorders: achalasia, gastroparesis, chronic intestinal pseudo-obstruction and so on, and functional disorders: dyspepsia, irritable bowel syndrome and a myriad of clinical syndromes and descriptions. The distinction between both groups was largely based on whether a propulsive failure was or not demonstrated by conventional imaging tests. Thus, a patient with recurrent abdominal pain and distension could be categorized either as a chronic intestinal pseudoobstruction (if dilated loops of bowel were visualized on Xrays) or irritable bowel syndrome (if nothing obviously abnormal was found). Application of more sophisticated and discriminating diagnostic tests (intestinal manometry, barostat, etc.) and histology increasingly showed that Gastrointestinal motility and perception disorders re-visited