Marc A. Gladman

Rectal Hypo sensitivity

Rectal hyposensitivity (RH) relates to a diminished perception of rectal distension that is diagnosed during anorectal physiologic investigation. There have been few direct studies of this physiologic abnormality, and its contribution to the development of functional bowel disorders has been relatively neglected. However, it appears to be common in patients with such disorders, being most prevalent in patients with functional constipation with or without fecal incontinence. Indeed, it may be important in the etiology of symptoms in certain patients, given that it is the only “apparent” identifiable abnormality on physiologic testing. Currently, it is usually diagnosed on the basis of elevated sensory threshold volumes during balloon distension in clinical practice, although such a diagnosis may be susceptible to misinterpretation in the presence of altered rectal wall properties, and thus it is uncertain whether a diagnosis of RH reflects true impairment of afferent nerve function. Furthermore, the etiology of RH is unclear, although there is limited evidence to support the role of pelvic nerve injury and abnormal toilet behavior. The optimum treatment of patients with RH is yet to be established. The majority are managed symptomatically, although “sensory-retraining biofeedback” appears to be the most effective treatment, at least in the short term, and is associated with objective improvement in the rectal sensory function. Currently, fundamental questions relating to the contribution of this physiologic abnormality to the development of functional bowel disorders remain unanswered. Acknowledgment of the potential importance of RH is thus required by clinicians and researchers to determine its relevance.

rectal Hyposensitivity : prevalence and Clinical Impact in Patients With Intractable Constipation and Fecal Incontinence

AbstractPURPOSE: Blunted rectal sensation, or rectal hyposensitivity, has been reported anecdotally in patients with functional disorders of evacuation and continence. The purpose of this study was to determine the prevalence of rectal hyposensitivity and whether the finding of such an abnormality was associated with any clinical impact. METHODS: One thousand three hundred fifty-one patients, referred for anorectal physiologic investigation, were divided according to presenting symptoms into the following categories: constipation (subdivided into infrequency of and/or obstructed defecation), fecal incontinence (subdivided into passive, postdefecation, and urge incontinence), fecal incontinence and constipation, or “other.” Rectal hyposensitivity was judged to be present when at least one of the sensory threshold volumes was elevated beyond the normal range (mean plus 2 standard deviations). The prevalence of rectal hyposensitivity was then calculated in each group and in relation to other investigations. RESULTS: Rectal hyposensitivity was present in 16 percent of patients, with males and females equally affected. Twenty-three percent of patients with constipation, 10 percent of patients with fecal incontinence, 27 percent of patients with incontinence associated with constipation, and only 5 percent of patients with other symptoms were found to have rectal hyposensitivity. In patients with obstructed defecation, rectal hyposensitivity was present in 33 percent with rectocele, 40 percent with intussusception, and 53 percent with no mechanical obstruction evident on evacuation proctography. CONCLUSION: Rectal hyposensitivity is common in patients with constipation and/or fecal incontinence and may thus be important in the etiology of such conditions. Although the clinical relevance of this physiologic abnormality is unknown, its presence may have implications regarding the management of hindgut dysfunction and particularly the selection of patients for surgery.

Rectal intussusception in symptomatic patients is different from that in asymptomatic volunteers

Rectal intussusception is a common finding at evacuation proctography in both symptomatic and asymptomatic individuals. Little information exists, however, as to whether intussusception morphology differs between patients with evacuatory dysfunction and healthy volunteers.

Systematic Review of Surgical Options for Idiopathic Megarectum and Megacolon

Objective:A subgroup of patients with intractable constipation has persistent dilatation of the bowel, which in the absence of an organic cause is termed idiopathic megabowel (IMB). The aim of this systematic review was to evaluate the published outcome data of surgical procedures for IMB in adults. Methods:Electronic searches of the MEDLINE (PubMed) database, Cochrane Library, EMBase, and Science Citation Index were performed. Only peer-reviewed articles of surgery for IMB published in the English language were evaluated. Studies of all surgical procedures were included, providing they were performed on 3 or more patients, and overall success rates were documented. Studies were critically appraised in terms of design and methodology, inclusion criteria, success, mortality and morbidity rates, and functional outcomes. Results:A total of 27 suitable studies were identified, all evidence was low quality obtained from case series, and there were no comparative studies. The studies involved small numbers of patients (median 12, range 3–50), without long-term follow-up (median 3 years, range 0.5–7). Inclusion of subjects, methods of data acquisition, and reporting of outcomes were extremely variable. Subtotal colectomy was successful in 71.1% (0%–100%) but was associated with significant morbidity related to bowel obstruction (14.5%, range 0%–29%). Segmental resection was successful in 48.4% (12.5%–100%), and recurrent symptoms were common (23.8%). Rectal procedures achieved a successful outcome in 71% to 87% of patients. Proctectomy, the Duhamel, and pull-through procedures were associated with significant mortality (3%–25%) and morbidity (6%–29%). Vertical reduction rectoplasty (VRR) offered promising short-term success (83%). Pelvic-floor procedures were associated with poor outcomes. A stoma provided a safe alternative but was only effective in 65% of cases. Conclusions:Outcome data of surgery for IMB must be interpreted with extreme caution due to limitations of included studies. Recommendations based on firm evidence cannot be given, although colectomy appears to be the optimum procedure in patients with a nondilated rectum, restorative proctocolectomy the most suitable in those with dilatation of the colon and rectum, and VRR in those patients with dilatation confined to the rectum. Appropriately designed studies are required to make valid comparisons of the different procedures available.

Rectal hyposensitivity: a disorder of the rectal wall or the afferent pathway? An assessment using the barostat.

OBJECTIVE:Rectal hyposensitivity (RH) relates to a diminished perception of rectal distension. Diagnosis on the basis of abnormal threshold volumes on balloon distension alone may be inaccurate due to the influence of differing rectal wall properties. The aim of this study was to investigate whether RH was actually due to impaired afferent nerve function or whether it could be secondary to abnormalities of the rectal wall.METHODS:A total of 50 patients were referred consecutively to a tertiary referral unit for physiologic assessment of constipation (Rome II criteria), 25 of whom had associated fecal incontinence. Thirty patients had RH (elevated threshold volumes on latex balloon distension), and 20 patients had normal rectal sensation (NS). Results were compared with those obtained in 20 healthy volunteers (HV). All subjects underwent standard anorectal physiologic investigation, and assessment of rectal compliance, adaptive response to isobaric distension at urge threshold, and postprandial rectal response, using an electromechanical barostat.RESULTS:Mean rectal compliance was significantly elevated in patients with RH compared to NS and HV (p < 0.001). However, 16 patients with RH (53%) had normal compliance. Intensity of the urge to defecate during random phasic isobaric distensions was significantly reduced in patients with RH compared to NS and HV (p < 0.001). The adaptive response at urge threshold was reduced in patients with RH compared to NS and HV (p < 0.001), although spontaneous adaptation at operating pressure was similar in all three groups studied (p= 0.3). Postprandially, responses were similar between groups.CONCLUSION:In patients found to have RH on simple balloon distension, impaired perception of rectal distension may be partly explained in one subgroup by abnormal rectal compliance. However, a second subgroup exists with normal rectal wall properties, suggestive of a true impairment of the afferent pathway. The barostat has an important role in the identification of these subgroups of patients.

Clinical and physiological findings, and possible aetiological factors of rectal hyposensitivity†

Rectal hyposensitivity (RH) relates to insensitivity of the rectum on anorectal physiological investigation and appears common in functional bowel disorders. The clinical significance of this physiological abnormality is unclear.

In Patients With Slow Transit Constipation, the Pattern of Colonic Transit Delay Does Not Differentiate Between Those With and Without Impaired Rectal Evacuation

BACKGROUNDSevere constipation may be subclassified on the basis of speed of colonic transit and efficacy of rectal evacuation. It is hypothesized that rectal evacuatory disorder (RED) may be associated with a secondary transit delay.OBJECTIVESTo determine whether scintigraphy can discriminate between slow transit constipation (STC) with or without coexistent RED on the basis of progression of isotope throughout the colon and by analyses of specific regions of interest.METHODSOne hundred ninety-six patients with STC (radio-opaque marker study) were subclassified according to results of proctography into those with a RED (STC-RED N = 30) or normal (STC-ONLY N = 41) evacuation. Patients subsequently underwent colonic scintigraphy. Distribution of generalized or left-sided patterns of colonic transit was assessed. Severities of transit delay and regional transit at specific time points were also evaluated.RESULTSTime–activity curves and severity of global transit delay were similar between groups as were the incidences of generalized and left-sided patterns of delay. Percentage of radioisotope retention in the right colon at 18 h was higher for the STC-ONLY group (P < 0.05), but this was poorly discriminative. No differences were observed for the percentage of radioisotope retained in the left colon at later scans.CONCLUSIONSGlobal and regional assessment of colonic transit by scintigraphy failed to discriminate between patients with STC with or without coexistent RED. Thus, RED is not associated with a specific pattern of transit delay and scintigraphy alone cannot predict the presence or absence of RED, knowledge of which is important for management.

Manometric, Sensorimotor, and Neurophysiologic Evaluation of Anorectal Function

With advances in diagnostic technology, it is now accepted that in the field of functional bowel disorders, symptom-based assessment is unsatisfactory as the sole means of directing therapy. A robust taxonomy based on underlying pathophysiology has been suggested, highlighting a crucial role for physiologic testing in clinical practice. A wide number of complementary investigations currently exist for the assessment of anorectal structure and function, some of which have a clinical impact in patients with functional disorders of evacuation and continence by markedly improving diagnostic yield and altering management. The techniques, limitations, measurements, and clinical use of manometric, sensorimotor, and neurophysiologic tests of anorectal function are presented.

Neuroanatomy and physiology of colorectal function and defaecation: from basic science to human clinical studies

Abstract  Colorectal physiology is complex and involves programmed, coordinated interaction between muscular and neuronal elements. Whilst a detailed understanding remains elusive, novel information has emerged from recent basic science and human clinical studies concerning normal sensorimotor mechanisms and the organization and function of the key elements involved in the control of motility. This chapter summarizes these observations to provide a contemporary review of the neuroanatomy and physiology of colorectal function and defaecation.

Fecal Incontinence: Community Prevalence and Associated Factors--A Systematic Review.

BACKGROUND: Fecal incontinence is a chronic and debilitating condition with significant health burden. Despite its clinical relevance, the prevalence of fecal incontinence remains inconsistently described. OBJECTIVE: This study aimed to systematically review the literature regarding the prevalence of and factors associated with fecal incontinence among community-dwelling adults. DATA SOURCES: A search of the PubMed, Embase, and Cochrane databases was performed. STUDY SELECTION: Studies that reported the prevalence of fecal incontinence and/or associated factors in a community-based (ie, unselected) adult population were included. Two independent assessors reviewed eligible articles. MAIN OUTCOME MEASURES: Relevant data were extracted from each study and presented in descriptive form. The main outcome measures included the prevalence of fecal incontinence (adjusted and/or unadjusted), stratified for age and sex if reported; factors associated (and not associated) with fecal incontinence; and study quality, assessed using predefined criteria. RESULTS: Of 3523 citations identified, 38 studies were included for review. The reported median prevalence of fecal incontinence was 7.7% (range, 2.0%–20.7%). Fecal incontinence equally affected both men (median, 8.1%; range, 2.3%–16.1%) and women (median, 8.9%; range, 2.0%–20.7%) and increased with age (15–34 years, 5.7%; >90 years, 15.9%). The study populations and diagnostic criteria used were heterogeneous, precluding any meaningful pooling of prevalence estimates. Study quality assessment revealed 6 high-quality studies, of which only 3 were performed in a representative sample. The median prevalence of fecal incontinence was higher in these studies at 11.2% (range, 8.3%–13.2%). The factors most commonly reported to be associated with fecal incontinence included increasing age, diarrhea, and urinary incontinence. LIMITATIONS: Heterogeneity of studies precluded meaningful pooling or meta-analysis of data. CONCLUSIONS: Fecal incontinence is a prevalent condition of equal sex distribution, affecting ≈1 in 8 community adults, and has identifiable associated factors. The paucity of high-quality prevalence studies emphasizes the need for future population-based studies that use standardized diagnostic criteria for fecal incontinence.