Rectal hyposensitivity and functional anorectal outlet obstruction are common entities in patients with functional constipation but are not significantly associated

Clinical significance and related factors of rectal hyposensitivity in patients with functional defecation disorder

Background

Rectal hyposensitivity (RH) is not uncommon in patients with functional defecation disorder (FDD). FDD patients with RH are usually unsatisfied with their treatment.

Aims

The aim of this study was to find the significance of RH in patients with FDD and the related factors of RH.

Methods

Patients with FDD first completed clinical questionnaires regarding constipation symptoms, mental state, and quality of life. Then anorectal physiologic tests (anorectal manometry and balloon expulsion test) were performed. Rectal sensory testing (assessing rectal response to balloon distension using anorectal manometry) was applied to obtain three sensory thresholds. Patients were separated into three groups (non-RH, borderline RH, and RH) based on the London Classification. The associations between RH and clinical symptoms, mental state, quality of life, and rectal/anal motility were investigated.

Results

Of 331 included patients with FDD, 87 patients (26.3%) had at least one abnormally elevated rectal sensory threshold and 50 patients (15.1%) were diagnosed with RH. Patients with RH were older and mostly men. Defecation symptoms were more severe (p = 0.013), and hard stool (p < 0.001) and manual maneuver (p = 0.003) were more frequently seen in the RH group. No difference in rectal/anal pressure was found among the three groups. Elevated defecatory desire volume (DDV) existed in all patients with RH. With the number of elevated sensory thresholds increasing, defecation symptoms got more severe (r = 0.35, p = 0.001). Gender (male) (6.78 [3.07-15.00], p < 0.001) and hard stool (5.92 [2.28-15.33], p < 0.001) were main related factors of RH.

Conclusion

Rectal hyposensitivity plays an important role in the occurrence of FDD and is associated with defecation symptom severity. Older male FDD patients with hard stool are prone to suffer from RH and need more care.

Digital Rectal Examination Is a Valuable Bedside Tool for Detecting Dyssynergic Defecation: A Diagnostic Study and a Meta-Analysis

BACKGROUND

Accurate dyssynergic defecation (DD) diagnosis depends on anorectal physiological tests that are not widely available.

AIM

The purpose of this study is to evaluate the diagnostic yield of digital rectal examination (DRE) compared with anorectal physiological tests in diagnosing DD in patients with constipation.

METHODS

A total of 218 chronic constipation patients who fulfilled the Rome IV diagnostic criteria for functional constipation (FC) and underwent a standardized DRE and high-resolution anorectal manometry (HRAM) test were enrolled in this study. The diagnostic accuracy of DRE compared with HRAM was evaluated, and the agreement between DRE and HRAM was calculated. Furthermore, a comprehensive literature search on PubMed, Web of Science, Cochrane Library, and Embase database was conducted to further elucidate the pooled diagnostic accuracy of DRE in DD patients.

RESULTS

A total of 101 patients (46.33%) had a DD pattern using HRAM, while 117 patients (53.67%) were diagnosed without DD. The sensitivity of DRE in diagnosing dyssynergia was 71.3%, and the specificity was 76.1%. There was a moderate agreement between DRE and HRAM for diagnosing DD (κ-coefficient = 0.474, P < 0.001). Meanwhile, six studies (including our study) comprising 964 constipated patients were included in our meta-analysis. The outcomes demonstrated that the AUC was 0.85 (95% CI 0.82-0.88) with 77% summary sensitivity (95% CI 65-86) and 80% summary specificity (95% CI 71-86) to diagnose DD.

CONCLUSIONS

DRE could be a valuable tool for screening DD. Our study revealed acceptable sensitivity and specificity of DRE in detecting dyssynergia compared with the physiological tests. Meanwhile, our study highlights that DRE remains an important tool in clinical practice.

Imaging and clinical assessment of functional defecatory disorders with emphasis on defecography

Functional defecation disorders (FDD) encompass causes of constipation associated with anorectal dysfunction, which include dyssynergia or inadequate defecatory propulsion. FDD are frequently encountered in clinical practice and may affect up to 33-50% of patients with chronic constipation. The etiology of FDD is unclear, however, it has been defined as an acquired, but subliminal behavioral disorder. Pathophysiologic mechanisms may include discoordination of rectoanal muscles, paradoxical contraction or insufficient relaxation of puborectalis and/or anal sphincter during defecation, and sluggish colonic transit. A combination of comprehensive clinical assessment, digital rectal examination and a battery of physiologic tests are needed to make an accurate diagnosis of FDD. Defecography may play a crucial role in the evaluation of FDD, especially when a balloon expulsion test (BET) and/or anorectal manometry (ARM) are equivocal or demonstrate contradictory results. In this review, we provide a thorough overview of the epidemiology, pathophysiology, diagnostic criteria, clinical and imaging evaluation, and treatment options for FDD, with an emphasis on available diagnostic imaging tools such as defecography and conventional fluoroscopic methods.

Ameliorating Effects of Transcutaneous Electrical Acustimulation at Neiguan (PC6) and Zusanli (ST36) Acupoints Combined with Adaptive Biofeedback Training on Functional Outlet Obstruction Constipation

Background

Stimulant laxatives are still considered the most common treatment for functional outlet obstruction constipation (FOOC). However, the effectiveness of laxatives is unsatisfactory, and the long-term use of laxatives may cause certain adverse events. With this in mind, it is, however, paramount that novel complementary treatment(s) and/or other forms of alternative medicine are adequately investigated.

Aims

The study aims to explore the effects and potential mechanism(s) of transcutaneous electrical acustimulation (TEA) combined with adaptive biofeedback training (ABT) on FOOC.

Methods

A total of forty-five patients with FOOC were recruited and were randomly assigned to receive either Macrogol 4000 Powder (MAC, 10 g bid) (group A, n = 15) only, ABT + MAC + Sham-TEA (group B, n = 15), or TEA + ABT + MAC (group C, n = 15) in a six-week study. Individual patients' constipation-symptoms (PAC-SYM) and constipation-quality of life (PAC-QOL) were both assessed and scored. Serum acetylcholine (Ach) and nitric oxide (NO) were measured from drawn blood samples while individual patients' heart rate variability (HRV) was calculated at baseline and after each corresponding therapy. Anorectal manometry and balloon expulsion test were both performed before and after treatment.

Results

Firstly, participants in group C had significantly lower scores of PAC-SYM, PAC-QOL, and a decreased anal defecating pressure (ADP) as compared to participants in group B (all p < 0.050). These results, however, suggest the TEAs effect. Secondly, the low-frequency band (LF)/(LF + HF) ratio in groups B and C were decreased as compared to group A (p=0.037, p=0.010, respectively) regarding HRV. On the other hand, the high-frequency band (HF)/(LF + HF) ratio in groups B and C showed an opposite outcome. Finally, the serum Ach in groups B and C was significantly higher as compared to group A (p=0.023, p=0.012, respectively). Of significant importance, the serum NO in groups B and C were notably low as compared to group A (p=0.001, p < 0.001, respectively).

Conclusions

TEA, combined with ABT, effectively improves constipation symptoms as well as QOL in FOOC patients. It is, however, achieved by decreasing ADP, which mechanisms are mediated via the autonomic and enteric mechanisms.

Poststroke Constipation Is Associated With Impaired Rectal Sensation

OBJECTIVES

Constipation is prevalent in individuals after stroke. However, the pathophysiological mechanisms of poststroke constipation remain unclear. This study was designed (i) to investigate the difference in anorectal motility and rectal sensation among stroke patients with constipation, stroke patients without constipation, and healthy controls (HC), (ii) to evaluate the impact of stroke sites on constipation and rectal sensation, (iii) to explore the role of autonomic functions, and (iv) to determine the independent risk factors for poststroke constipation.

METHODS

Seventy-one stroke patients and 24 HC were recruited. General information, clinical characteristics, and relevant questionnaires were collected. Meanwhile, an anorectal manometry test was performed to assess functions of anorectal motility and rectal sensation, and an electrocardiogram was recorded to evaluate autonomic functions.

RESULTS

(i) Constipation patients exhibited increased rectal sensation thresholds, compared with patients without constipation or HC (P < 0.001). Almost no difference was detected in anorectal motility parameters among 3 groups. Constipation-associated clinical characteristics, such as spontaneous bowel movements, were weakly or moderately correlated with rectal sensation thresholds (P < 0.05 to P < 0.001 for various parameters). (ii) Patients with brainstem lesions had increased prevalence of constipation and first sensation threshold, compared with patients without brainstem lesions (P = 0.045, P = 0.025, respectively). (iii) There was a weak positive correlation between sympathetic activity and stroke severity and a weak negative one between vagal activity and stroke severity. Rectal sensation thresholds were positively and weakly correlated with sympathetic activity but negatively with vagal activity. (iv) The desire of defecation threshold and the physical activity were independent risk factors for poststroke constipation (P = 0.043, P = 0.025, respectively).

DISCUSSION

Poststroke constipation is characterized by elevated thresholds for rectal sensation, rather than altered anorectal motility. Patients with brainstem lesions are predisposed to constipation possibly because of the disruption of afferent pathway from the rectum to the brain. Moreover, the desire of defecation threshold and the physical activity level are factors independently associated with poststroke constipation.

Prokinetics in the Management of Functional Gastrointestinal Disorders

PURPOSE OF REVIEW

The goal of this review is to review the current status of prokinetics and to place it in historical context. Impaired motility and thus propulsion have long been thought to play important roles in the pathogenesis of a number of gastrointestinal disorders including gastroesophageal reflux disease (GERD), gastroparesis, chronic idiopathic pseudo-obstruction, and constipation. Historically, disordered motility was also thought to contribute to a number of functional gastrointestinal disorders such as functional dyspepsia (FD) and irritable bowel syndrome (IBS).

RECENT FINDINGS

As we learn more of the pathophysiology of FD, IBS, GERD, constipation, and gastroparesis, the limitations of a therapeutic strategy based on the stimulation of motility (i.e., the use of a prokinetic) have become apparent and the disappointments of the past explained. The development of prokinetic drugs has also been hampered by the non-selective nature of many of the agents studied to date which resulted in some unexpected side effects. There is still an unmet need for an effective and safe prokinetic, but drug development in this area must be mindful of the challenges of the area and the need for selectivity for a given target receptor.

Rectal Hyposensitivity Is Associated With a Defecatory Disorder But Not Delayed Colon Transit Time in a Functional Constipation Population

The physiological mechanism of functional constipation (FC) includes defecatory disorders and delayed colon transit. About 18% to 68% constipated patients may have rectal hyposensitivity (RH). We performed this study to investigate the association between RH and functional defecatory disorder (FDD) as well as that between RH and delayed colon transit in FC patients.A total of 218 FC patients were enrolled. The constipation severity instrument (CSI) was used to assess constipation symptoms. High-resolution anorectal manometry (HR-ARM), defecography, balloon expulsion tests, and colon transit studies were performed for each patient. RH was defined as 1 or more sensory threshold pressures raised beyond the normal range based on HR-ARM. We investigated the association between RH and constipation symptoms, and the occurrence of FDD and delayed CTT. Ninety FDD patients completed the initial phase of biofeedback treatment (BFT). We investigated the association between RH and the effect of BFT.Totally 122 (56.0%) patients had RH. The total CSI (49.82 ± 1.09 vs 41.25 ± 1.55, P = 0.023) and obstructive defecation subscale scores (23.19 ± 0.69 vs 17.07 ± 0.90, P < 0.001) were significantly higher in RH than in non-RH patients. No significant difference was observed in slow transit symptoms (21.77 ± 0.72 vs 19.90 ± 0.85, P = 0.121) or abdominal pain (6.85 ± 2.61 vs 5.00 ± 1.04, P = 0.380). The frequency of prolonged CTT was not significantly different between RH and non-RH groups (54.1% vs 58.3%, P = 0.403). RH patients rated more occurrence of FDD (72.1% vs 53.1%, P = 0.014) and dysynergic defecation (79.8% vs 50.2%, P = 0.004) than non-RH patients, whereas no differences were seen for inadequate defecatory propulsion (59.2% vs 55.0%, P = 0.589). After BFT, the proportion of "no effect" was significantly higher in the RH group than in the non-RH group (22.4% vs 9.4%, P = 0.010).RH is associated with obstructive defecation symptoms and the occurrence of FDD. Further studies are needed to detect the mechanism of RH's effect on BFT and FC.

Rectal prolapse traumatizes rectal neuromuscular microstructure explaining persistent rectal dysfunction

PURPOSE

Internal rectal prolapse is common and correlates with age. It causes a plug-like physical obstruction and is a major cause of defecation disorder. The progressive distortion of the prolapsing rectum likely causes secondary defects in the rectal wall, which may exacerbate rectal dysfunction. We undertook a prospective observational study to detect and quantify the neurologic and histopathologic changes in the rectal wall.

METHODS

We examined dorsal and ventral rectal wall specimens from consecutive patients with internal rectal prolapse undergoing stapled transanal rectal resection (STARR). We subjected specimens to histopathologic and neuropathologic assessment, including immunohistochemistry. We also recorded patients' clinical and demographic characteristics and sought correlations between these and the pathologic findings.

RESULTS

We examined 100 specimens. The severity of rectal prolapse and the extent of descent of the perineum correlated significantly with age. Concomitant hemorrhoidal prolapse was noted in all male patients and in 79 % of female patients. Muscular and neuronal defects were detected in 94 and 90 % of the specimens, respectively. Only four specimens (4 %) were free of significant structural defects.

CONCLUSION

Rectal prolapse traumatizes the rectum causing neuromuscular defects. The tissue trauma is due to shearing forces and ischemia caused by the intussusception. This initiates a self-reinforcing vicious circle of physical and functional obstruction, further impairing rectal evacuation and causing constipation and incontinence. The correlation between extent of prolapse and age suggests that internal rectal prolapse can be considered a degenerative disorder. Neural and motor defects in the wall of the rectum caused by rectal prolapse are likely irreversible.