Evolving concepts in chronic constipation in Europe and elsewhere: not worlds apart

Abnormal neuronal response to rectal and anal stimuli in patients with idiopathic fecal incontinence

BACKGROUND

The pathophysiology behind idiopathic fecal incontinence (IFI) is poorly understood. We hypothesized abnormal sensory pathways along the brain-gut axis as a key player in this disease, reflected in cortical evoked potentials (CEP) from mechanical stimuli of the rectum and the anal canal.

METHODS

CEPs were recorded during repeated rapid balloon distensions of the rectum and anal canal in 19 women with IFI (mean age: 60 ± 14, mean Wexner score: 14.7 ± 2.9) and in 19 healthy women (mean age: 56 ± 11, mean Wexner score: 1.1 ± 1.3). Latencies, amplitudes and topography of CEPs elicited by rectal distension were compared between the groups. CEPs from both rectal and anal distensions were examined using spectral band analysis of single sweeps determining the relative amplitude of five spectral bands as a proxy of neuronal processing.

KEY RESULTS

Compared to controls IFI patients had prolonged latency of CEPs from rectal distension by up to 27% (p < 0.001) while amplitudes and topography were similar (all p > 0.7 and all p > 0.23). Spectral analysis of CEPs from rectal distensions showed no difference (all p > 0.1) between groups. However, analysis of CEPs following distension of the anal canal resulted in abnormally low activity in beta (8-12 Hz; p < 0.001) band and high activity in the gamma (32-70 Hz; p = 0.04) band in patients.

CONCLUSIONS & INFERENCES

IFI seems to be associated with impaired ano-rectal sensory functions in both the afferent fibers to the brain and the cortical processing of anal sensory pathways. This may play a central role for the pathogenesis of IFI.

Chronic constipation: a critical review

Chronic constipation is a very common symptom that is rarely associated with life-threatening diseases, but has a substantial impact on patient quality of life and consumption of healthcare resources. Despite the large number of affected patients and the social relevance of the condition, no cost-effectiveness analysis has been made of any diagnostic or therapeutic algorithm, and there are few data comparing different diagnostic and therapeutic approaches in the long term. In this scenario, increasing emphasis has been placed on demonstrating that a number of older and new therapeutic options are effective in treating chronic constipation in well-performed randomised controlled trials, but there is still debate as to when these therapeutic options should be included in diagnostic and therapeutic algorithms. The aim of this review is to perform a critical evaluation of the current diagnostic and therapeutic options available for adult patients with chronic constipation in order to identify a rational patient approach; furthermore we attempt to clarify some of the more controversial points to aid clinicians in managing this symptom in a more efficacious and cost-effective manner.

Diagnostic testing for dyssynergic defecation in chronic constipation: meta-analysis

BACKGROUND

Dyssynergic defecation (DD) results from inadequate relaxation of the pelvic floor on attempted defecation. The prevalence of DD in patients with chronic constipation (CC) is not certain. Aims of this study are to estimate the prevalence of abnormal findings associated with DD across testing modalities in patients referred for physiological testing for CC.

METHODS

Systematic search of MEDLINE, EMBASE and PUBMED databases were conducted. We included full manuscripts reporting DD prevalence in CC, and specific findings at pelvic floor diagnostic tests. Random effects models were used to calculate pooled DD prevalences (with 95% CI) according to individual tests and specific findings.

KEY RESULTS

A total of 79 studies on 7581 CC patients were included. The median prevalence of any single abnormal finding associated with DD was 37.2%, ranging from 14.9% (95% CI 7.9-26.3) for absent opening of the anorectal angle (ARA) on defecography to 52.9% (95% CI 44.3-61.3) for a dyssynergic pattern on ultrasound. The prevalence of a dyssynergic pattern on manometry was 47.7% (95% CI 39.5-56.1). The prevalence of DD was similar across specialty and geographic area as well as when restricting to studies using Rome criteria to define constipation.

CONCLUSIONS & INFERENCES

Dyssynergic defecation is highly prevalent in CC and is commonly detected across testing modalities, type of patient referred, and geographical regions. We believe that the lower prevalence of findings associated with DD by defecography supports use of manometry and balloon expulsion testing as an initial evaluation for CC.