AN ASSESSMENT OF INVESTIGATIONS FOR EVACUATORY DYSFUNCTION

Abstract

Normal defecation is a complex physiological act that requires proper co-ordination between several organs and is heavily influenced by various extrinsic factors like diet. Difficulty in evacuation can lead to constipation. Chronic constipation affects a significant proportion of the population and poses a significant medical and economic burden to any country. Common investigations for chronic constipation were evaluated with a systematic review and clinical studies. Systematic review of anorectal manometry (ARM), the balloon expulsion test (BE) and fluoroscopic evacuation proctography (EP) for constipation showed wide variation in the diagnostic yield of these tests along with significant variation in test methodology and data interpretation. A proctographic study involving healthy volunteers confirmed that a range of so-called structural abnormalities can exist in health. Constipation is often a symptomatic diagnosis. Symptoms incorporated within the Rome III criteria, one of the most widely used diagnostic criterion for constipation, were unable to reliably predict the final proctographic diagnosis in a cohort of constipated patients. Agreement between ARM, BE and EP for the diagnosis of subtypes of constipation was assessed prospectively in consecutive patients satisfying the Rome III criteria for functional constipation. Despite strict adherence to the Rome III criteria, agreement between recommended investigations was poor. The final diagnosis was influenced by the choice of investigation. Chronic constipation is an enigmatic disorder. The confusion is further compounded by a lack of consensus on investigation protocols and the absence of a recognized 'gold standard' test. In order to identify the elusive 'gold standard', and hence reach a consensus, large and well-designed studies that can assess the clinical utility of these investigations are urgently required.