ABBREVIATIONS
APM
anopouch manometry
ARM
anorectal manometry
CD
Crohn’s disease
DRE
digital rectal examination
FAP
familial adenomatous polyposis
FI
fecal incontinence
IBS
irritable bowel syndrome
IMA
inferior mesenteric artery
IPAA
ileal pouch-anal anastomosis
IV
intravenous
LAR
low anterior resection
MRI
magnetic resonance imaging
RAIR
rectoanal inhibitory reflex
UC
ulcerative colitis
US
ultrasound
INTRODUCTION
Anorectal disorders specifically functional pelvis floor disorders are defined by their symptoms and in some cases require abnormal diagnostic tests including anorectal manometry (ARM), balloon expulsion, and defecography. Presentations of these disorders range from constipation and impaired evacuation to excessive pain or uncontrolled passage of fecal material. The classification of functional pelvic floor diseases continues to evolve with the most recent Rome IV criteria consisting of three main categories: functional defecation disorders, functional anorectal pain syndromes, and fecal incontinence (FI). By definition, the establishment of a function diagnosis requires the absence of structural or inflammatory disorders. However, those with prior colorectal and pelvic surgeries can be at increased risk for functional disorders. Additionally, patients with altered anatomy with structural and inflammatory disorders can have concomitant functional disorders.
FUNCTIONAL PELVIC FLOOR DYSFUNCTION
Functional Defecation Disorders
Patients with functional defecation disorders will often have an incomplete evacuation, frequent straining, and often use manual maneuvers to aid defecation. Ineffective emptying of the rectum in these disorders occurs secondary to poor coordination of the pelvic muscles, specifically the puborectalis, and the external anal sphincter muscles. Previously, these disorders had a variety of descriptors including anismus, paradoxical puborectalis contraction, pelvic floor dyssynergia, outlet obstruction constipation, and spastic pelvic floor syndrome. Currently, these conditions are defined as functional defecation disorders by the Rome IV criteria with the subtypes of dyssynergic defecation and inadequate defecatory propulsion.
Dyssynergic Defecation
Patients with dyssynergic defecation are not able to effectively defecate secondary to uncoordinated contractions and relaxations of the anal sphincter and rectal muscles. Through inappropriate contraction and failure to relax the puborectalis muscle and external anal sphincter, the anorectal angle is narrowed, and the pressure is increased in the anal canal making evacuation less effective ( Fig. 33.1 ). Patients will often report excessive straining, bloating, and incomplete evacuation.
To meet this diagnosis, patients must meet the Rome IV criteria for chronic constipation or irritable bowel syndrome (IBS) with constipation as well as having two or more objective testing for impaired evacuation. Impaired evacuation is diagnosed with an abnormal balloon expulsion test, abnormal evacuation pattern on manometry, and/or impaired rectal evacuation by imaging ( Table 33.1 ).
| 1. The patient must satisfy diagnostic criteria for functional constipation and/or IBS with constipation | |
| 2. During repeated attempts to defecate, there must be features of impaired evacuation, as demonstrated by two of the following three tests: |
|
| 3. Subtypes of functional defecation disorders |
|
Dyssynergic Defecation of the Pouch
Patients who have undergone restorative proctocolectomy and ileal pouch-anal anastomosis (IPAA) can also have dyssynergic defecation including a primary form with the absence of concurrent structural or inflammatory abnormalities and a secondary form with structural and inflammatory abnormalities including pouchitis, cuffitis, Crohn’s disease (CD) of the pouch. , Additionally, those with inflammation of the pouch, specifically chronic pouchitis, are at an increased risk of developing dyssynergic defecation when compared to those without inflammation. In patients with pouches, dyssynergic defecation presents similarly with a sense of incomplete evacuation, bloating, excessive straining, manipulation of body position to facilitate defecation. To diagnose patients with this pouch evacuation disorder they also must have abnormal objective testing including abnormal balloon expulsion testing, ARM, or defecography ( Fig. 33.2 ).
Inadequate Defecatory Propulsion
Patients with inadequate defecatory propulsion must meet the Rome IV criteria for functional defecation disorders and will often have a similar presentation to dyssynergic defecation. Manometry will show inadequate forces to promote expulsion with elevated anal pressure in comparison to rectal pressure. This can be seen in patients with normal anatomy as well as patients with pouches.
Pelvic Pain Syndromes
Pelvic pain can be a symptom of several structural pelvic, anorectal, and sacral disorders. Functional anorectal pain occurs in the absence of structural or pathologic process of the pelvic floor with additional conditions in those with anatomical pathology. Functional anorectal pain syndromes are distinguished based on the duration of pain and anorectal tenderness. Previously chronic proctalgia was the overarching term for several functional anorectal pain syndromes. However, by the most recent Rome Criteria, this condition is now categorized by its sub-conditions: levator ani syndrome, unspecified anorectal pain, and proctalgia fugax ( Table 33.2 ).
| A. Levator ani syndrome |
|
| B. Unspecified functional anorectal pain syndrome | Symptom criteria for chronic levator ani syndrome but no tenderness during posterior traction on the puborectalis muscle |
| C. Proctalgia fugax |
|
Levator Ani Syndrome
Patients will typically describe a vague, dull pain or pressure sensation high in the rectum. The pain is often exacerbated by sitting and defecation but improves with standing, lying down, and or walking and does not typically awaken patients from sleep. This syndrome occurs more frequently in females aged 30 to 60. The Rome IV criteria for levator ani syndrome include chronic or recurrent rectal pain or aching, lasting 30 minutes or longer with tenderness during traction on the puborectalis. DRE is key to making this diagnosis and may reveal spasms and tenderness of the levator ani muscles. To diagnose a patient with levator ani syndrome, other causes of rectal pain must be excluded. The etiology of levator ani syndrome is unknown however it is hypothesized that there is likely spasm of the pelvic floor and elevated anal resting pressures as well as anorectal incoordination. ,
Unspecified Anorectal Pain
Unspecified anorectal pain is recognized by the Rome IV criteria and is similar to levator ani syndrome with similar pain that lasts 30 minutes or longer. However, unspecified anorectal pain does not have puborectalis tenderness.
Proctalgia Fugax
Finally, the third Rome IV functional anorectal pain syndrome is proctalgia fugax in which patients experience sudden, severe rectal pain lasting seconds to minutes with a maximum duration of 30 minutes. Between these episodes, there is no rectal pain. Pain may awaken patients from sleep and can be relieved by defecation, walking, or soaking in the tub. , , The etiology is thought to be secondary to anal smooth muscle dysfunction with possible triggering by stressful events and anxiety.
Pouchalgia Fugax
Patients with pouchalgia fugax, who almost exclusively are male, typically present with recurrent sudden pain, lasting seconds to minutes and being not associated with defecation. The pain in pouchalgia fugax is generated deep in the pouch body, often corresponding to the contraction of puborectalis muscle.
Sawtooth Contractions of the Pouch
Patients with sawtooth pattern contraction-related pouch pain experience fluctuating sharp or pressure pain at the anus, corresponding to the spasm of the internal anal sphincter ( Fig. 33.3 ). Concurrent anal fissure, ulcers, cuffitis, and mucosal prolapse are common. There may be some clinical and manometric overlap between levator ani syndrome and sawtooth contractions.
Coccygodynia
Coccygodynia should remain in the differential for patients with pelvic pain but is not considered a functional anorectal pain syndrome. In patients with coccygodynia, patients have pain located in and around the coccyx without low back pain or radiculopathy. Patients will typically complain of pain at the site of the tailbone, provoked by sitting. Symptoms may last for weeks or months. Coccygodynia usually results from trauma including vaginal deliveries or arthritis and is more common in obese patients and females. Movement of the coccyx on digital rectal examination (DRE) will reproduce the pain. In addition, a physical exam must include inspection for other etiologies including pilonidal cysts or fistulas as well as palpation for a coccygeal mass.
Fecal Incontinence
Fecal incontinence is defined as the recurrent uncontrolled passage of fecal material for at least 3 months. It is defined solely by its symptoms and does not require further anorectal physiological testing. The etiology of FI is often multifactorial including the weak pelvic floor, stool consistency, and impaired colorectal storage capacity, with anal sphincter weakness being the most frequently identified abnormality. Diarrhea, rectocele, stress urinary incontinence, and increased body mass index are most commonly associated with FI. , Pelvic floor disorders including rectal prolapse and descending perineum syndrome as well as disorders affecting rectal capacity or sensation including CD, ulcerative colitis (UC), and radiation proctitis can also lead to FI. Sphincter trauma from fistulas, fissures, or obstetrical injuries can all cause FI. Surgical procedures, including hemorrhoidectomy, internal sphincterotomy, and fistulectomy, pouch creation, anterior resections, can lead to anal sphincter weakness and FI ( Fig. 33.1 ).
DIAGNOSIS AND DIFFERENTIAL DIAGNOSIS
Clinical Assessment
A detailed history of the patient’s symptoms as well as bowel habits including frequency of bowel movements, stool consistency, and straining, are important to making a diagnosis. Red flag symptoms including unintentional weight loss, changes in stool caliber, and rectal bleeding should be assessed and should prompt further endoscopic evaluation. Surgical and obstetric histories are important as they are risk factors for many functional syndromes. A family history of colorectal malignancies should also be elicited. Chronic symptoms that have not improved with conservative measures are more suggestive of a functional disorder over acute onset symptoms.
Rectal Examination
A careful rectal examination is critical to making the diagnosis in patients with functional anorectal disorders. Patients should be positioned in the left lateral decubitus position. The area should be inspected for fistulas, fissures, external hemorrhoids, and prior surgical scars. A DRE must be performed to evaluate for masses, rectoceles, strictures, fecal impactions, and increased sphincter pressure. The levator muscles and the coccyx should be palpated to assess for pain. The patient should then be instructed to bear down to simulate defecation with attention being paid to the degree of perineal descent and the relaxation of the external anal sphincter. Approximately 80% of the resting anal canal pressure is contributed by the internal anal sphincter. The external sphincter contributed about 20% of the resting anal canal pressure; to evaluate the external sphincter the patient can be asked to squeeze the examiner’s finger. A DRE performed by an experienced examiner has a high concordance with manometric testing for dyssynergic defecation and FI with a sensitivity of >90%. ,
Endoscopy
Endoscopic examination should be based on this history and physical examination and is necessary if patients have any red flag symptoms including unintentional weight loss, change in stool caliber, and rectal bleeding or if the patient is not up to date with colorectal cancer screening.
Colonoscopy/Flexible Sigmoidoscopy : Colonoscopy and flexible sigmoidoscopy allow for direct visualization of the colonic mucosa and evaluate for obstructing masses, fistulas, fissures, ischemic colitis, prolapse, segmental colitis-associated diverticulitis, and strictures. However, in a patient without red flag symptoms with chronic constipation, the yield of colonoscopy for constipation alone is similar to asymptomatic patients undergoing evaluation for colon cancer screening. , Colonoscopy or flexible sigmoidoscopy should be considered in patients with diarrhea, change in bowel habits, red flag symptoms, or not up to date with colorectal cancer screening to obtain endoscopic assessment of the rectosigmoid mucosa and to evaluate for alternative etiologies.
Pouchoscopy : Pouchoscopy is a valuable modality in the diagnosis and differential diagnosis of ileal pouch disorders. Pouchoscopy has been used to identify pouch anatomy, mucosal inflammation stricture, fistula, or anastomotic leak. Histologic evaluation is important for the differential diagnosis of inflammatory and functional pouch disorders. Villous blunting and infiltration of mononuclear cells in the lamina propria may be a part of colonic metaplasia of the ileum mucosa from long-term fecal stasis. Patients with chronic pouchitis and/or cuffitis are at increased risk of secondary dyssynergic defecation. On the other hand, dyssynergic defecation may cause distal anterior pouch or cuff prolapse or inflammation. ,
Anoscopy : Anoscopy is the best method for viewing the anal canal and allows closer inspection of the anal canal, dentate line, and distal rectum evaluating for hemorrhoids, anal fissures, and fistulas.
Cross-Sectional Imaging
Cross-sectional imaging including computed tomography (CT) and magnetic resonance imaging (MRI) is particularly useful for the evaluation of structural abnormalities. In patients with CD imaging is complementary to endoscopic evaluation and is useful in the evaluation of intramural and extraluminal abnormalities, such as strictures, fistulas, sinuses, and abscesses. Following pelvic surgeries, complications are best imaged with CT or MRI. However, for many functional disorders, dynamic imaging is preferred.
Computed Tomography and Computed Tomography Enterography : For initial evaluation of suspected CD and surveillance, CT enterography is the optimal imaging for most patients. , CT enterography assesses for alternative diagnoses as well as the complications of CD including abscesses, fistulas, and strictures. , The decision to choose CT enterography versus CT abdomen and pelvis with intravenous (IV) contrast depends on the patient’s ability to drink large volumes of contrast required for enterography as well as the patients’ acuity. Though CT enterography can find more subtle abnormalities, a standard CT is preferable in severely ill patients ( Fig. 33.4 ).
Computed tomography is not recommended as a first-line imaging for pelvic floor abnormalities including in the evaluation of FI and dyssynergic defecation. However, in a patient following pelvic floor surgeries, CT with IV contrast is an ideal imaging modality to assess acute conditions postoperatively including abscesses and hematomas.
Magenatic Resonance Imaging and Magnetic Resonance Enterography : Magnetic resonance enterography has similar sensitivity and specificity to CT enterography and given the lack of ionizing radiation has become ideal for monitoring of CD. , , Quality of MR enterography is more variable than CT enterography as motion artifacts from patient movement as well as respiratory and bowel-motion artifacts. , Drinking a large volume of oral contrast and the time required for the test, limit its utility in many patients.
In patients with concern for functional defecation disorders, more dynamic studies including MR and fluoroscopy defecography are preferred. For FI, an MRI of the pelvis specifically of the anal sphincter using an endoanal coil may be used. Endoanal MRI is not universally available but does have improved evaluation of atrophy of the external anal sphincter and abnormalities of the pelvic floor musculature including the levator ani muscle complex compared to endoanal ultrasound (US) ( Fig. 33.5 ).
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