The irritable colon syndrome

Abstract

Summary 1. The term “irritable colon syndrome” is used to embrace a variety of colonic functional disturbances which can be divided into two main clinical groups, (a) spastic colon, (b) chronic simple diarrhoea. 2. Aetiological factors which appear to be of importance in the condition include psychological disturbances, an attack of dysentery, dietary habits, specific sensitivity to certain foods and abuse of purgatives. 3. The outstanding symptom of spastic colon is pain. This may occur over any part of the colon but is most common over the descending and sigmoid colon. When the pain occurs over the hepatic flexure, gall-bladder disease is often suspected; when over the transverse colon, a peptic ulcer, and when over the splenic flexure, disease of the heart, oesophagus or left lung. The pain may be either continuous or intermittent and is often partly relieved by defaecation. The bowel action is often normal, but there may be constipation alternating with short bursts of diarrhoea. When constipation is present, clear mucus is often passed per rectum and the term “mucous colitis” has been applied to these cases, but it is a misnomer as there is no histological evidence of disease and should therefore be abandoned. 4. The patients with chronic simple diarrhoea as their sole gastro-intestinal symptom may have either continuous or intermittent symptoms over the course of many months or years. 5. The diagnosis of irritable colon syndrome depends upon both positive and negative evidence. On the negative side, exclusion of major organic disease is an essential. On the positive side, both sigmoidoscopy and a barium enema examination may yield evidence favouring the diagnosis. 6. The radiological aspects of the disorder are considered in detail. A barium enema examination plays an essential part in diagnosis and it fulfils two separate functions. On the one hand, it assists in the exclusion of organic disease. On the other, it can yield valuable positive evidence to support the diagnosis. To obtain reliable positive evidence it is necessary to avoid heavy preparation of the patient with purgatives and colon washouts with irritating solutions; and the examination itself should be made with a plain barium enema suspension free from agents which stimulate the colon. Under these conditions, a reduced size of lumen, and increased number of haustral markings and (in more severe cases) actual segmental spasms, are strong evidence in support of the diagnosis. The post-evacuation appearances may also yield positive support. 7. The radiological findings have been correlated with the results of a colonic motility study of these patients. Under resting conditions, patients with spastic colon have evidence of excessive colonic motility on their pressure tracings, while those with chronic diarrhoea display somewhat less motor activity than normal subjects, yet on barium enema examination these two classes of patient yield appearances which are closely similar and which, in the great majority of cases, give evidence of “irritability.” This similarity of the barium enema appearances corresponds with the motility patterns observed after an injection of prostigmine, when patients with the irritable colon syndrome are likely to show excessive motor activity, irrespective of whether their symptomatology is that of spastic colon or of chronic diarrhoea and also irrespective of whether they are in a stage of symptoms or are symptom-free at the time of observation.