Digital rectal examination in defecatory disorders: Is it poor man's anorectal manometry?

Pratik Sethiya; Meghraj Ingle; Mayur Gattani; Vikas Pandey; Shamshersingh Chauhan; Sneha Deshpande; Saiprasad Lad; Gaurav Kumar Singh; B Kiran; Swapnil Walke; Megha Meshram; Akash Shukla

doi:10.4103/ghep.ghep_21_22

ORIGINAL ARTICLE

Year : 2022 | Volume : 2 | Issue : 4 | Page : 160-165

Digital rectal examination in defecatory disorders: Is it poor man's anorectal manometry?

Pratik Sethiya¹, Meghraj Ingle¹, Mayur Gattani¹, Vikas Pandey², Shamshersingh Chauhan¹, Sneha Deshpande¹, Saiprasad Lad¹, Gaurav Kumar Singh¹, B Kiran¹, Swapnil Walke¹, Megha Meshram³, Akash Shukla³
¹ Department of Gastroenterology, LTMMC and LTMGH, Sion, Mumbai, Maharashtra, India
² Department of Radiology, LTMMC and LTMGH, Sion, Mumbai, Maharashtra, India
³ Department of Gastroenterology, Seth G. S. Medical College and K. E. M. Hospital, Mumbai, Maharashtra, India

Date of Submission	28-Jul-2022
Date of Decision	26-Aug-2022
Date of Acceptance	30-Aug-2022
Date of Web Publication	13-Oct-2022

Correspondence Address:
Akash Shukla
New Building, 9^th Floor, Department of Gastroenterology, Seth G. S. Medical College and K. E. M. Hospital, Parel, Mumbai - 400 012, Maharashtra
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ghep.ghep_21_22

Abstract

Background and Aims: Magnetic resonance defecography (MRD) and high-resolution anorectal manometry (HR-ARM) are considered gold standards for defining pelvic floor anatomy and diagnosis of dyssynergic defecation (DD) respectively. Digital rectal examination (DRE) is a bedside test which may be used to screen for DD. The objective of the study was to evaluate the usefulness of DRE as compared with HR-ARM and MRD for detection of DD. Materials and Methods: Sixty patients of functional constipation defined by ROME-IV criteria were enrolled. After ruling out structural causes of constipation using colonoscopy, all patients were subjected to undergo DRE and subsequently HR-ARM and BET, blinded to DRE findings. MRD was reported by a radiologist who was also blinded to the findings of DRE and HR-ARM. The diagnostic yield of DRE was compared with HR-ARM and MRD. Results: Dyssynergia was diagnosed in 48/60 (80%) patients on DRE and in 44/60 (73%) patients on ARM. The sensitivity, specificity, and positive predictive value (PPV) of DRE in diagnosing DD were 95.90%, 57.14%, and 83.83%, respectively (P = 0.01). Among clinical features, only digital maneuvering while defecation correlated with DD (P = 0.019). On DRE, paradoxical anal sphincter contraction correlated with DD (P = 0.010). The presence of excessive descent on DRE correlated with excessive anorectal descent on MRD. Structural abnormalities such as rectocele, cystocele, vaginal prolapse, and uterine prolapse were associated with DD in all. Conclusion: DRE is a useful bedside test in diagnosing DD with a high sensitivity and PPV. DRE is poor in identifying structural abnormalities contributing to DD.

Keywords: Anorectal manometry, dyssynergic defecation, magnetic resonance defecography

How to cite this article:
Sethiya P, Ingle M, Gattani M, Pandey V, Chauhan S, Deshpande S, Lad S, Singh GK, Kiran B, Walke S, Meshram M, Shukla A. Digital rectal examination in defecatory disorders: Is it poor man's anorectal manometry?. Gastroenterol Hepatol Endosc Pract 2022;2:160-5

How to cite this URL:
Sethiya P, Ingle M, Gattani M, Pandey V, Chauhan S, Deshpande S, Lad S, Singh GK, Kiran B, Walke S, Meshram M, Shukla A. Digital rectal examination in defecatory disorders: Is it poor man's anorectal manometry?. Gastroenterol Hepatol Endosc Pract [serial online] 2022 [cited 2023 Jun 2];2:160-5. Available from: http://www.ghepjournal.com/text.asp?2022/2/4/160/358473

Introduction

Chronic constipation (CC) is a common problem in the community all over the world.^[1],[2],[3] Dyssynergic defecation (DD) also known as pelvic floor dyssynergia, obstructed defecation, outlet obstruction, or anismus is a common cause of functional constipation.^[4],[5] They affect 10%–25% of the population. In cases of refractory and severe constipation, anorectal physiologic tests such as balloon expulsion test (BET) and high-resolution anorectal manometry (HR-ARM) should be performed. The first modalities to evaluate these patients are digital rectal examination (DRE) and BET. BET has the sensitivity and specificity in diagnosing DD and when compared with HR-ARM was 85% and 71%.^{[4],[5],[6],[7]} However, in a resource-limited setting, even DRE is an excellent measure in diagnosing DD where HR-ARM is not available.^[8],[9] Magnetic resonance defecography (MRD) is regarded as standard modality of diagnosing the structural etiology of pelvic floor dysfunction.^[10]

Materials and Methods

Study population

Patients who are diagnosed to have functional constipation by ROME-IV criteria were enrolled and included in the study.^[11] Sixty patients with written informed consent were enrolled at a tertiary care hospital in Mumbai, India, over a period of 1 year. Patients with functional constipation were subjected to DRE followed by colonoscopy, HR-ARM, and MRD. DRE and colonoscopy were performed by an expert investigator. The radiologist reporting the MRD was blinded to the findings of DRE and HR-ARM. DRE findings were also blinded to the expert performing HR-ARM. To diagnose patients as DD patients, the following criteria were used:^[12]

Should have functional constipation by ROME-IV criteria
Dyssynergic pattern of defecation (Types I–IV) on HR-ARM
One of the following: (a) Inability to expel 50-mL water-filled balloon within 1–2 min and (b) inability to evacuate or ≥50% retention of contrast during defecography. However, HR-ARM was considered standard modality of diagnosing DD.

Patients with anal fissure, hemorrhoids, fecal incontinence, per rectal bleeding, pregnancy or lactation, and age <18 years were excluded. The study was approved by the institutional review and ethics committee.

Methodology and interpretation

Digital rectal examination

All DREs were performed by a single investigator after patients' consent in left lateral position with lignocaine as lubricating jelly inspection of perineal skin such as excoriations, skin tags, anal fissures, or hemorrhoids. The anal resting tone was determined. The anal squeeze pressure was assessed by asking the subject to squeeze and asked to push and simulate defecation. Both were classified as normal, decreased, or increased. During squeeze, the abdominal push effort, anal sphincter relaxation, and perineal descent were assessed. Perineal descent was categorized as normal, absent, or excessive. Anal sphincter relaxation was classified as normal, impaired relaxation, or paradoxical contraction. The presence of any two of the following findings was used to clinically diagnose dyssynergia on DRE: unable to contract abdominal muscles, impaired anal sphincter relaxation, paradoxical anal sphincter contraction, and absent perineal descent.^[5],[13]

Magnetic resonance defecography

All examinations were performed with a Philips 3T superconducting closed configuration magnetic resonance imaging (MRI) system. MRI would be done after 250 cc of aqueous sonographic gel instilled into the rectum through a small rectal catheter with the patient in the right decubitus position. MRD was done in four phases. Cine images were taken at rest, on Kegel maneuvers, at static phase, and at defecation phase. Interpretation of the images was done after these maneuvers by expertise in radiology. The pubococcygeal line, drawn on sagittal plane from the inferior aspect of the pubic symphysis to the last coccygeal joint, is recommended as a reference line to measure pelvic organ prolapse. The protocol for interpretation for MRD was as per standard protocol and guidelines.^[14],[15] Grading of structural abnormalities was done as small, medium, and large. Rectal descent, bladder decent, vaginal decent, and enterocele all were graded as small – <3 cm, medium – 3–6 cm, and large –>6 cm. The diagnosis of paradoxic contraction DD required two of three features: absence of perineal descent, retention of more than two-thirds of the contrast gel, and inappropriate contraction of puborectalis or inadequate opening of the anal sphincter canal.^[15] Rectocele was graded as <2 cm – small, 2–4 cm – moderate, and >4 cm – large.^[16]

High-resolution anorectal manometry

HR-ARM was performed on Medical measurement system (MMS), Laborie, USA, which works on water perfusion-based system in all CC patients. The procedure included an assessment of rectoanal pressure at rest and during squeeze along with the presence of dyssynergia and type of it. Balloon expulsion test was performed prior to HR-ARM. Defecation index was calculated as the maximum rectal pressure divided by the minimum anal sphincter pressure. Values ≤1.4 were considered abnormal. Normative ARM data were obtained from previously published laboratory standards, resting anal sphincter pressure (mean, 72 mmHg; 95% confidence interval [CI], 64–80 mmHg; and mean, 65 mmHg; 95% CI, 56–74 mmHg in normal male and female patients, respectively), and maximal squeeze pressure (mean, 193 mmHg; 95% CI, 175–211 mmHg; and mean, 143 mmHg; 95% CI, 124–162 mmHg in normal male and female patients, respectively).^{[8],[15],[17]}

Balloon expulsion test

The patient was made to lie in left lateral decubitus with flexion of the knees and hips. Empty balloon is gently inserted into the rectum and inflated to 50 ml with water or until the patients feel a desire to defecate. The patient was then asked to expel balloon in sitting position and was provided privacy for the same. Unable to expel the balloon in sitting posture after 1 min was considered abnormal. However, the BET also can be performed in left lateral decubitus. If the patient is not able to evacuate the balloon, increasing weight is added to the hanging end of the catheter. A need for more than 250 g added weight to evacuate the balloon is suggestive of DD. Both the methods of BET were equally efficacious in the diagnosis of DD.^{[2],[18],[19]}

Colonoscopy of the patients was done using colonoscope from Olympus model name: 150-GIF.

Data analysis

We compared the findings of DRE with that of HR-ARM, BET, and MRD. The sensitivity, specificity, and positive and negative predictive values of DRE in the diagnosis of dyssynergia were determined in patients with functional constipation. DD, paradoxical anal sphincter contraction along with digital maneuvering on DRE was compared with patients having DD on HR-ARM. Excessive descent on DRE was compared with anorectal descent on MRD and dyssynergia on MRD was compared with DD on HR-ARM. All structural etiologies of constipation encountered on MRD were compared with DD on HR-ARM, DRE, and BET.

Statistical analysis

Statistical significance was used to evaluate the correlation between DRE findings with HR-ARM MRD, and BET. Data analysis was performed by Statistical Package of Social Science (SSPS) software, IBM, USA. Likelihood ratio and Pearson Chi-square test were the statistical tests applied and P < 0.05 was considered statistically significant.

Results

Baseline characteristics of study population

Sixty patients of functional constipation were enrolled, of which 56.66% (34/60) were female. The median age of presentation was 45.5 years (range: 18–69). There were 44 patients diagnosed with DD by HR-ARM, of which 71.42% were female. Type 1 DD was the most common seen in 78% of the patients, whereas Types 2 and 3 were seen in 9% and 13%, respectively. There was no case of Type 4 DD reported. Solitary rectal ulcer syndrome was diagnosed in 10% (6/60) of patients on colonoscopy. All of them had DD on HR-ARM. The most common BSS score was 3 (73.3%) followed by BSS – 2 (23.3%). The patient characteristics are illustrated in [Table 1].

Table 1: Patient characteristics

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Findings on digital rectal examination

There were a total of 42 patients who fulfilled the criteria of DD by HR-ARM along with either an abnormal BET or MRD. All of them were diagnosed by HR-ARM. A total of 40 (95.23%) patients were diagnosed with DD by DRE. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DRE in diagnosing dyssynergia were 95.24%, 55.56%, 83.33%, and 83.33%, respectively, when compared with HR-ARM. Ninety percent (54/60) of patients had normal squeeze when compared with patients having DD on HR-ARM. 33.33% (20/60) of patients had a high resting anal tone which when compared with DD on HR-ARM was statistically significant (P = 0.007). Digital maneuvering was noted in 72.72% of patients with DD when compared with dyssynergia on HR-ARM, which was statistically significant (P = 0.018).

Paradoxical anal sphincter contraction was observed in 90.90% in patients having DD on HR-ARM (P = 0.010). Comparing symptoms of constipation and DD on DRE and HR-ARM is shown in [Table 2].

Table 2: Comparing symptoms of constipation and dyssynergic defecation on digital rectal examination and high-resolution anorectal manometry

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Results and findings of high-resolution anorectal manometry

Forty percent of patients with high anal tone on DRE had high resting anal resting pressures on HR-ARM (P = 0.057). 96.15% had normal squeeze on DRE, and normal squeeze on HR-ARM (P = 0.019) was statistically significant. 13.6% had increased squeeze pressure on DRE when compared with DD on HR-ARM. The defecation index <1.4 was seen in 72.2% (32/44). The mean resting anal pressures were 58.46 mmHg with a maximum of 96 mmHg and minimum of 35 mmHg. The mean anal squeeze pressure was 123.93 mmHg with a minimum of 87mmHg and maximum of 198 mmHg. Among patients with DD, the mean maximum rectal pressure is 116.3 mmHg whereas the minimal anal sphincter pressure is 69.8 mmHg. Comparing DRE with HR-ARM is shown in [Table 3].

Table 3: Comparing digital rectal examination with high-resolution anorectal manometry

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Findings on balloon expulsion test

Impaired BET was defined as patients not able to expel balloon in 60 s and patients not able to expel the balloon at all. Eighty percent of patients with impaired BET had DD on HR-ARM (P = 0.251). Ninety percent of the patients with DD on DRE had impaired BET (P = 0.059). Twenty-five percent of patients with impaired BET had dyssynergia on MRD. Comparing dyssynergia on BET with DRE, HR-ARM, and MRD is shown in [Table 4].

Table 4: Comparing dyssynergia on balloon expulsion test with digital rectal examination, high-resolution anorectal manometry, and magnetic resonance defecography

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Observations made on magnetic resonance defecography

Moderate rectocele was seen in (34/60) 56.66% of patients and 6/60 (10%) had mild rectocele. 64.70% of patients with moderate rectocele had DD on HR-ARM (P = 0. 212), which was not significant. When compared, 50% of the patients with anorectal descent had excessive descent on DRE (P = 0.252), which was not statistically significant. 47.05% of patients with rectocele had excessive descent (P = 0.075). All patients with spastic perineum syndrome had DD on HR-ARM (P = 0.015). Fifty percent of patients with DD on DRE have spastic perineum syndrome (P = 0.039), which was statistically significant. Vaginal prolapse (23.52%) and cystocele (22.72%) were noted in patients with DD on HR-ARM. The analysis of associated anatomical factors on MRD with dyssynergia on DRE, HR-ARM, and BET is shown in [Table 5]. Comparing dyssynergia and increased anorectal descent on MRD with DRE and HR-ARM is shown in [Table 6].

Table 5: Analysis of associated anatomical factors on magnetic resonance defecography with dyssynergia on digital rectal examination, high-resolution anorectal manometry, and balloon expulsion test

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Table 6: Comparing dyssynergia and increased anorectal descent on magnetic resonance defecography with digital rectal examination and high-resolution anorectal manometry

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Discussion

The present study highlights the role of DRE in today's era of HR-ARM and MRD in diagnosing DD. This study is unique, as for the first time, the findings of DRE are compared with MRD.

Symptoms in the present study associated with DD were compared with Ghoshal^[2] and Rao et al.^[20] such as incomplete stool evacuation (90.90% vs. 97.4% vs. 75%), excessive strain (81.18% vs. 96% vs. 85%), and digital evacuation (72.2% vs. 58.2% vs. 66%). Among total patients with DD, 71.42% were female, which states that females had predominant etiology of functional constipation as DD.

It was found that DD was found in 67% of the patients in the present study as compared with Ghoshal et al.^[8] in 34% of patients and by Jain et al.^[21] in 45% of patients. However, this was a clinical observation made in the present study, which states that a high prevalence of DD might be present among CC. DRE is a useful test in diagnosing DD with high sensitivity (95.23%) and PPV (83.31%) in the present study, making it an excellent screening test in diagnosing DD as the etiology of CC. Patients with increased anal tone significantly correlated with DD on HR-ARM (P = 0.007). Similarly, studies by Soh et al.,^[9] Tantiphlachiva et al.,^[5] and Jain et al.^[22] found sensitivity of DRE was (93.2% Vs 75% vs. 70%), respectively, and PPV of DRE was (91% vs. 97% vs. 82%), respectively, in the diagnosis of DD .It was also stated by Ghoshal et al.^[23] in its position paper “Indian consensus on chronic constipation in adults” that DRE has high sensitivity , specificity , PPV and NPV for diagnosing DD. Thus, Eastern as well as Western data suggest DRE as a reliable predictor of DD.

In the present study and work by Tantiphlachiva et al.,^[5] patients with normal squeeze on DRE had normal anal squeeze pressure on HR-ARM (P = 0.019). It was found that patients with high anal tone on DRE had high anal resting pressures on HR-ARM (P = 0.057). However, only 13.6% of patients with increased squeeze pressure on DRE had DD on HR-ARM (P = 0.159). Hence, the present study and the study by Tantiphlachiva et al.^[5] both have demonstrated that the sphincter defects in DD are minimal.

In the present study the sensitivity, specificity, PPV, and NPV of BET in diagnosing DD on BET, was lower when compared with Minguez et al.^[19] The sensitivity, specificity, PPV, and NPV of BET in diagnosing DD were 87.5%, 64%, 89%, and 97%, respectively. According to Chiarioni et al.,^[24] PPV was 67.9% and NPV was 80.9% in diagnosing DD when it was compared with HR-ARM. Eighty percent of patients with impaired BET had DD on HR-ARM. Furthermore, the present study compared abnormal BET with the presence of rectocele on MRD, which showed that about 70% of patients with abnormal BET had rectoceles (P = 0.603). Thus, with good sensitivity, BET is an additional bedside tool in clinching the diagnosis of DD. It also suggests that structural etiologies like rectocele are also important factors in prolongation of BET.

MRD identifies structural etiologies contributing to DD in patients with constipation. In the present study, among patients with functional constipation, 57% had moderate rectocele and 10% had mild rectocele. A majority of patients (64.70%) with moderate rectocele had DD on HR-ARM. However, Reiner et al.^[25] stated that 39% of patients with DD had rectoceles. The present study stated a low prevalence of excessive anorectal descent when compared with Reiner et al.^[25] (29% vs. 78%). There were no studies comparing DRE findings of excessive descent with anorectal descent on MRD; however, the present study compared the variables. The sensitivity, specificity, PPV, and NPV in comparing excessive descent on DRE with excessive anorectal descent on MRD were 66.66%, 78.94%, 60%, and 83.33%, respectively (P = 0.252). Furthermore, dyssynergia on DRE significantly correlated with dyssynergia on MRD (P = 0.039) in the present study, which again states the importance of DRE as a useful bedside tool. Dyssynergia on MRD significantly correlated with dyssynergia on HR-ARM (P = 0.015), consistent with Heinrich et al.^[15] In patients with DD on HR-ARM, both cystocele and vaginal prolapse were present in 22.7% (P = 0.710) and 23.52% (P = 0.791) of cases, respectively. This states that structural abnormalities such as rectoceles, excessive anorectal descent, cystoceles, and vaginal prolapse can be the cause of dyssynergia in patients, which needs evaluation by MRD.

Thus, DRE when combined with BET complements in identifying DD, and MRD recognizes anatomical abnormalities contributing to constipation and dyssynergia. It was for the first time that DRE findings were compared with all three modalities like MRD, HR-ARM, BET and the findings were compared with each other. This makes this study unique.

The limitation of our study was that it has a small sample size. Colonic transit studies were not done in patients with functional constipation. However, the present study emphasized the use of DRE and BET in diagnosing DD, and enlightened about the presence of structural etiologies in cases of functional constipation and dyssynergia.

Conclusion

DRE is a useful bedside test in diagnosing dyssynergia with high sensitivity and PPV when compared with HR-ARM. MRD remains a useful modality in identifying structural etiologies for constipation as well as dyssynergia. Therapeutic implication of HR-ARM in dyssynergia is biofeedback therapy, which is available only in highly specialist units and has compliance issues with patients.^[26] Hence, combining DRE and MRD in the initial evaluation of identifying the etiology of constipation can be put forward as there is poor adherence to biofeedback therapy after HR-ARM. Our study highlights the necessity of including MRD in the evaluation of constipation and most importantly that physicians and gastroenterologists perform accurate DRE routinely in the evaluation of constipation.

Acknowledgment

We acknowledge the Department of Radiology for performing MRD as and when required and Mrs. Megha Meshram for performing anorectal manometry.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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