Internal anal sphincter dysfunction in neurogenic faecal incontinence

Spontaneous Internal Anal Sphincter Relaxation During High-resolution Anorectal Manometry Is Associated With Peripheral Neuropathy and Higher Charlson Comorbidity Scores in Patients With Defecatory Disorders

Background/Aims

We aimed to evaluate associations between comorbidities, peripheral neuropathy, and spontaneous internal anal sphincter relaxation (SAR) in patients with defecatory disorders.

Methods

A patient was considered to exhibit SAR during high-resolution anorectal manometry (HR-ARM) when the nadir pressure is < 15 mmHg and the time from onset to relaxation was ≥ 15 seconds in the resting pressure frame. A case-control study was performed using HR-ARM data collected from 880 patients from January 2010 to May 2015. We identified 23 cases with SAR (median age 75 years; 15 females; 12 fecal incontinence and 11 constipation). We compared HR-ARM values, Charlson index comorbidity scores, neuropathy, and the prevalence of diseases that potentially cause neuropathy between controls and SAR patients. Each SAR case was compared to 3 controls. Controls were selected to match the age, gender, and examination year of each SAR case.

Results

Compared to controls (26.1%), SAR patients (52.2%) exhibited a significantly higher frequency of fecal incontinence. SAR patients also had higher Charlson index scores (5 vs 4, P = 0.028). Nine of 23 SAR patients (39.1%) exhibited peripheral neuropathy— this frequency was higher than that for the control group (11.6%; P = 0.003). Diseases that potentially cause neuropathy were observed in 17 of 23 SAR cases and 32 of 69 controls (P = 0.022).

Conclusions

SAR develops in patients with constipation and fecal incontinence but is more common in patients with fecal incontinence. Our controlled observational study implies that SAR is associated with peripheral neuropathy and more severe comorbidities.

Neurophysiological testing in anorectal disorders

The neurophysiological techniques currently available to evaluate anorectal disorders include concentric needle electromyography (EMG) of the external anal sphincter, anal nerve terminal motor latency (TML) measurement in response to transrectal electrical stimulation or sacral magnetic stimulation, motor evoked potentials (MEPs) of the anal sphincter to transcranial magnetic cortical stimulation, cortical recording of somatosensory evoked potentials (SEPs) to anal nerve stimulation, quantification of electrical or thermal sensory thresholds (QSTs) within the anal canal, sacral anal reflex (SAR) latency measurement in response to pudendal nerve or perianal stimulation, and perianal recording of sympathetic skin responses (SSRs). In most cases, a comprehensive approach using several tests is helpful for diagnosis: needle EMG signs of sphincter denervation or prolonged TML give evidence for anal motor nerve lesion; SEP/QST or SSR abnormalities can suggest sensory or autonomic neuropathy; and in the absence of peripheral nerve disorder, MEPs, SEPs, SSRs, and SARs can assist in demonstrating and localizing spinal or supraspinal disease. Such techniques are complementary to other methods of investigation, such as pelvic floor imaging and anorectal manometry, to establish the diagnosis and guide therapeutic management of neurogenic anorectal disorders.

Intra-anal and rectal application of l-erythro methoxamine gel increases anal resting pressure in healthy volunteers

Background

This study examined the effect of a single local application of l-erythro methoxamine, an α1-adrenoceptor agonist, on mean anal resting pressure (MARP) and cardiovascular variables in healthy volunteers.

Methods

l-Erythro methoxamine gel was administered in a single-blind manner; 0·3–3 per cent gels were applied perianally (n = 12), 1–3 per cent gels intra-anally (n = 16) and 1 per cent gel rectally (n = 8). MARP, systolic blood pressure, diastolic blood pressure and pulse rate were measured before application and for up to 6 h afterwards. Blood samples were taken to estimate plasma drug levels.

Results

Perianal gel produced no increase in MARP. Intra-anal 1 per cent and 3 per cent gel produced a significant rapid rise in MARP for 4 and 5 h respectively after application (P = 0·012 and P = 0·017 respectively). Rectal 1 per cent gel increased MARP for 2 h after application (P = 0·036). Intra-anal gel resulted in an increase in systolic blood pressure (1 per cent gel at 2 h, P = 0·042; 3 per cent gel at 4 h, P = 0·017). One per cent intra-anal and rectal gels caused a decrease in the pulse rate for 2 h after application (P = 0·012 and P = 0·018 respectively). Six subjects complained of nausea and three of headache after gel application.

Conclusion

Intra-anal and rectal gel produced a sustained rise in MARP with rapid onset in volunteers. This raises the possibility of a therapeutic application for l-erythro methoxamine in patients with passive incontinence and internal anal sphincter dysfunction.

Open study of low-dose amitriptyline in the treatment of patients with idiopathic fecal incontinence

INTRODUCTION

Amitriptyline, a tricyclic antidepressant agent with anticholinergic and serotoninergic properties has been used empirically in the treatment of idiopathic fecal incontinence with good results.

METHODS

An open study was conducted to test the response to amitriptyline 20 mg daily for four weeks by 18 patients (2 males) of median age 66 years with idiopathic fecal incontinence Incontinence scores, number of bowel movements, computerized ambulatory anorectal pressures, and pudendal nerve terminal motor latencies were evaluated before and after four weeks of therapy. Twenty-four control subjects (10 males) of median age 61 years were also assessed

RESULTS

Amitriptyline improved incontinence scores (median pretreatment score = 16 vs. median posttreatment score = 3; P < 0.001) and reduced the number of bowel movements per day (P < 0.001). Amitriptyline also decreased the frequency (median pretreatment frequency = 4.5 per hour vs. median immediate posttreatment frequency = 1.2 per hour (P < 0.05); control median frequency = 0.3 per hour) and the amplitude of rectal motor complexes (median pretreatment rectal pressure = 94 cm H2O vs. median immediate posttreatment rectal pressure = 58 cm H2O (P < 0.05); control median rectal pressure = 36 cm H2O) and improved anal pressures during these events (P < 0.001).

CONCLUSIONS

Amitriptyline improved symptoms in 89 percent of patients with fecal incontinence. The data support that the major change with amitriptyline is a decrease in the amplitude and frequency of rectal motor complexes. The second conclusion is that drug increases colonic transit time and leads to the formation of a firmer stool that is passed less frequently. These in combination may be the source of the improvement in continence.

Management of neurogenic fecal incontinence in myelodysplastic children by a modified continent appendiceal stoma and antegrade colonic enema

OBJECTIVES

Antegrade colonic enemas for neurogenic fecal incontinence via reverse reimplanted appendices (Mitrofanoff principle) have been primarily reported by Malone and coworkers in 1990. We used a modification of the described surgical technique and treated the first 10 patients with neurogenic fecal incontinence due to spina bifida. The surgical procedure and the results are reported.

METHODS

Since November 1991, we have used a surgical procedure similar to the appendiceal continence mechanism in urinary diversion to establish a continent colonic cutaneous stoma for antegrade enemas in 10 myelodysplastic patients (4 females, 6 males; median age 13.2 years [range 6 to 26]) with severe neurogenic fecal incontinence. The average follow-up is now 26.4 months (range 12.5 to 50). All patients had neurogenic bladder dysfunction successfully managed by clean intermittent catheterization, anticholinergic drugs, or artificial sphincter implantation. The surgical technique for fecal incontinence included the partial orthotopic submucosal imbedding of the appendix into a cecal tenia and the fixation of the ileocecal region at the inner side of the abdominal wall after creation of an appendicocutaneous catheterizable stoma.

RESULTS

All patients reached fecal continence for at least 38 hours (median 45.3) by using antegrade colonic enemas with 1.5% saline solution (n = 9) or GoLYTELY solution (n = 1), 0.5 to 1.5 L every 2 to 3 days. All other therapies (diet, oral medication, rectal purgative, or enema) to reach fecal continence had previously failed. There were only two complications seen at the follow-up. One boy with an artificial urinary sphincter presented with infection of the sphincter system, which led to explantation. Another boy presented 15 months after creation of the colonic appendiceal stoma with saline intoxication possibly due to a homemade saline solution.

CONCLUSIONS

We conclude that the antegrade colonic enema via an orthotopic continent appendiceal stoma is a safe and highly effective treatment modality for fecal incontinence in patients with neurogenic bowel dysfunction if nonsurgical management has failed.

Latency measurement of rectoanal reflexes

PURPOSE

Latency values of rectoanal reflexes may be altered in disorders of the pelvic floor. Evaluation of this relatively uninvestigated aspect of rectoanal reflexes may have diagnostic implications in patients with disorders of defecation.

METHODS

We studied the latency of rectoanal inhibitory and excitatory reflexes to sequential balloon distention of the rectum with 60 ml and 120 ml of air in 14 normal controls (mean age, 41.5 (range, 19-66) years), in 14 patients with fecal incontinence (FI) (mean age, 44.2 (range, 28-72) years), and in 14 patients with slow transit constipation (STC) (mean age, 40.6 (range 22-68) years).

RESULTS

The mean latency of inhibition (FI = 5.3 seconds; STC = 4.6 seconds; controls = 5.1 seconds) was remarkably similar for the three groups (P = 0.19). The mean latency of excitation in the proximal anal canal (FI = 2.8 seconds; STC = 2.5 seconds; controls = 2.8 seconds) was comparable in the three groups (P = 0.58). The mean latency of excitation in the distal anal canal (FI = 4.8 seconds; STC = 2.6 seconds; controls = 2.7 seconds) was prolonged in patients who were incontinent compared with the other two groups (P < 0.01).

CONCLUSIONS

Proximal rectoanal excitation and inhibitory reflexes, when present, have a constant latency, irrespective of the underlying condition. The different latency values for proximal and distal rectoanal excitatory reflexes in patients with FI may indicate disparate denervation damage to the external anal sphincter.

Sustained internal sphincter hypertonia in patients with chronic anal fissure

PURPOSE

This study was designed to determine whether functional variations of internal sphincter activity occur in order to differentiate between patients with anal fissures from those with hemorrhoids.

METHODS

Thirty patients with chronic anal fissure (median age, 28 years; 12 females), 22 patients with hemorrhoids (median age, 37 years; 7 females), and 33 control volunteers (median age, 48.5 years; 21 females) underwent ambulatory anal sphincter fine-needle electromyography and anorectal manometry.

RESULTS

The median internal sphincter electromyography frequency was similar: fissure group, 0.49 Hz; hemorrhoid group, 0.46 Hz (P > 0.05), and control group, 0.44 Hz (P > 0.05). Median anal resting pressures were similar in the fissure group (132 cm. H2O) and the hemorrhoids group (116 cm of H2O) (P > 0.05), but significantly greater than those in the control group (94 cm. H2O) (P < 0.05). The median number of transient relaxations of the internal and sphincter with an associated rise in rectal pressure and fall in anal pressure was 1 (range, 0-4) per hour in the fissure group, 6 (range, 4-7) per hour in the hemorrhoid group, and 4 range, 3-6) per hour in the control group. Six patients with fissures were reassessed following lateral internal sphincterotomy. Median and pressure was 102 cm of H2O (P > 0.1 vs. controls) and the number of internal sphincter relaxations increased to 4 per hour (P < 0.01 vs. preoperative number).

CONCLUSIONS

Internal anal sphincter relaxation occurs on fewer occasions in patients with chronic anal fissures that have failed to heal in comparison to patients with hemorrhoids and normal controls. This evidence further supports the hypothesis that internal sphincter hypertonia may be relevant to the pathogenesis of this disorder.

Rectoanal inhibition and incontinence in patients with rectal prolapse

Thirty-five patients with complete rectal prolapse, 32 with neurogenic faecal incontinence and 33 controls underwent ambulatory recording using a computerized anal electromyographic and anorectal manometry system. Median resting anal pressures were 34 cmH2O in patients with prolapse, 51 cmH2O in those with neurogenic faecal incontinence and 94 cmH2O in controls. Median basal rectal pressures were 18, 21 and 21 cmH2O respectively. High-pressure rectal waves of median amplitude 71 cmH2O lasting 30-150 s and associated with inhibition of the electromyographic activity of the internal and sphincter and a fall in anal pressures were seen in all patients with prolapse but not in controls or those with neurogenic incontinence. These waves were abolished following successful resection rectopexy. Recovery of continence occurs by abolition of high-pressure rectal waves, which produce maximal inhibition of sphincter activity before operation.