The Use of Standardized Questions in Identifying Patients with Dyssynergic Defecation.

backgroundDyssynergic defecation (DD) is present in approximately 30% of patients with idiopathic chronic constipation (CC). Diagnostic criteria for DD require objective testing such as anorectal manometry (ARM); yet, ARM remains a limited resource in Canada. The aim of this study is to determine the predictability of DD in patients with CC using a standardized self-reported symptom questionnaire.

methodIn this study, 166 consecutive English-speaking patients with CC who were referred for ARM completed a symptom questionnaire. DD was diagnosed if pelvic floor dyssynergy was demonstrated by ARM and balloon expulsion time was more than one minute. Likelihood ratios (LRs) were calculated for individual symptoms and prespecified symptom combinations. Likelihood ratios greater than five or less than 0.2 were considered significant. A recursive partitioning tree was used to find the symptoms best able to predict DD.

resultsNo single constipation symptom was sufficient to predict a diagnosis of DD. Patients who reported sometimes feeling an urge to defecate and a prolonged straining duration of greater than five minutes were more likely to have DD (LR = 7.74). In patients who reported straining often or always and had a short straining duration of less than two minutes, the diagnosis of DD was less likely (LR = 0.04). The recursive partitioning tree analysis similarly identified a sense of urge with a prolonged straining duration as predictor for DD, as well as an incomplete evacuation as another potential predictor.

conclusionQuestions regarding need to strain, duration of straining, urge to defecate, and incomplete evacuation are useful to predict the presence of DD in patients with CC. These questions will enable clinicians to make a clinical diagnosis of DD to guide treatment.