ABSTRACT
In the acute setting, colorectal dilatation may occur due to mechanical obstruction, pseudo-obstruction and severe inflammation/infection. The aetiology of the disabling condition remains poorly understood and the intriguing question of why some functional disorders have visceral dilatation in the colon/rectum or indeed anywhere in the gastrointestinal tract and others do not has not been answered. Whilst dilatation of the bowel may, in some cases, be so gross that it is apparent without invasive investigation, it is important to obtain objective evidence of the diagnosis of megabowel in less obvious cases and when surgery is contemplated. Formal diagnostic criteria for megacolon are limited due to lack of definition of the upper limit of normal for colonic diameter in the literature. Measurement of serum glucose, electrolytes and thyroid function tests is easy to perform but the diagnostic yield will be extremely low.
