Constipation is a term often used to describe a constellation of symptoms, including decreased frequency of bowel movements, a sensation of incomplete evacuation, significant straining with defecation, and prolonged toilet time. This spectrum of variable symptoms is often accompanied by abdominal discomfort or pain, a sensation of fullness, heaviness, and bloating, and can be coexistent with anorectal disease such as symptomatic hemorrhoidal disease, rectal prolapse, and anal fissure. Constipation prevalence is estimated to impact at least 10% of the population and is nearly twice as common in women compared to men, increasing with advancing age.¹ About one-third of chronic constipation cases in tertiary referral centers are due to rectal evacuation disorders,² whereas the majority do not involve a motility or evacuation disturbance and are referred to as normal transit (functional) constipation. Normal transit constipation is frequently termed chronic constipation and, if abdominal pain is relieved or exacerbated by bowel movements, is diagnosed as constipation-predominant irritable bowel syndrome (IBS-C). For research purposes, the Rome criteria, developed by expert consensus and validated in large populations, define constipation as having two or more characteristic features relating to frequency less than three bowel movements in a week and relationship of bowel movements to pain and sensation. Criteria include hard or lumpy stools, straining, a sense of incomplete evacuation, feeling of anorectal blockage or obstruction, or the need for digital maneuvers to assist defecation.³ Although a sudden change in bowel habits with a change in frequency or caliber of stools or the presence of symptoms such as unintentional weight loss or gastrointestinal (GI) bleeding warrants prompt evaluation for mechanical obstruction or luminal narrowing, the majority of patients experience chronic (defined as at least greater than 3 to 6 months and often years) symptoms that are not explained by biochemical assessment, cross-sectional imaging, or endoscopic evaluation. Constipation is often secondary in that it is a result of insufficient dietary fiber, a side-effect of medications (such as antihypertensives, antidepressants, antihistamines, or analgesics), diminished mobility (sedentary lifestyle), metabolic disorders (diabetes mellitus, chronic renal insufficiency), hormonal states (pregnancy), connective tissue disorders (scleroderma, Ehlers-Danlos), or neuropathic degeneration (Parkinson disease, multiple sclerosis).⁴ Rarely, constipation is a primary disorder related to slow transit such as chronic intestinal pseudo-obstruction or autoimmune gastrointestinal dysmotility. If primary, it is usually more prominently accompanied by upper GI and systemic symptoms including early satiety, weight loss, nausea, and vomiting. If slow transit constipation is suspected, before investigating a rare underlying primary disorder, it is imperative that a careful screening for secondary causes is completed and a disorder of rectal evacuation considered and treated if present because these may be the true explanations for the proximal motility disturbance phenotype.⁵ For this reason, as well as for guiding diagnostic and therapeutic interventions, constipation is typically categorized into subtypes (normal transit, slow transit, and defecatory dysfunction (also known as dyssynergia) based on an assessment of clinical or physiologic motility or transit evaluation and ease of evacuation. As diagnostic testing for assessments of physiologic function may not be widely available and as the approach to chronic constipation in clinical practice is algorithmic and fairly well-standardized independent of physiologic testing, the majority of patients are treated empirically based on a careful history and physical examination. Laboratory, radiographic, and endoscopic evaluation may be warranted. Regardless of etiology, chronic constipation has been shown to result in impaired quality of life, diminished work productivity and school attendance, and considerable economic and health care burden.⁴

When available, diagnostic testing can be beneficial. The two categories typically used to guide intervention are assessment for rectal evacuation disorders
and assessment for slow transit constipation via colonic transit assessment. Symptoms associated with chronic constipation are vague and variable, and it is essential to clarify what the patient is describing as constipation. In certain instances, the patient will complain of upper or middle GI symptoms such as bloating, nausea, and vomiting that may have their true origin in constipation. If constipation is suspected, in addition to inquiring about the frequency of bowel movements, patients should be asked about their sense of completeness of evacuation, degree of strain (if any), feeling like they “want to but can’t,” time spent on the toilet, use of digital maneuvers including stimulation and splinting the perineum as well as a description of stool form and caliber. The Bristol Stool Scale is a validated measure with varying pictorial stool consistencies ranging from small hard lumps (type 1) to liquid void of solid components (type 7) and may offer insight into the underlying issue and surrogate measure of motility (Fig. 55.1).⁶ Just as hard, separate lumps may represent slow transit, and watery stools may represent diarrhea or, conversely, liquid overflow around stool impacted in the rectum, or “pseudodiarrhea”. This heterogeneity of etiologies of loose stools highlights the importance of the digital rectal exam (DRE) and clarification of the patient’s sense of complete evacuation, experience of anorectal obstruction, or need for digital maneuvers.

Pelvic floor retraining by biofeedback therapy is a valuable tool in the management of constipation due to disordered defecation. A behavioral training technique introduced in 1987, biofeedback incorporates exercises,
repetition, and auditory and/or visual cues to optimize abdominopelvic coordination during simulated defecation. Biofeedback training includes an instrument in situ for an objective measure of physiologic functioning such as a manometry system, an air-filled balloon, EMG, ultrasound, or digital palpation with the aim of instructing the patient in coordinating abdominal and rectal propulsive force generation and puborectalis/sphincteric relaxation.²⁰ The goal of biofeedback is to correct and improve muscle control, which translates into actual function.²¹ Biofeedback should be carried out by an experienced physician, physiotherapist, or nurse with expertise in pelvic floor dysfunction. Exercises and simulation are repeated, modified, and corrected until the patient is able to perform successful maneuvers independently. In addition to biofeedback, patients should also be counseled comprehensively on bowel management techniques, including the physiology of the pelvic floor, diaphragmatic breathing and behavioral, nutritional, and lifestyle techniques, and nonpharmacologic options for treatment. Patients with hyposensitivity on initial evaluation may benefit from sensory retraining with a water-filled balloon, in which patients learn to discriminate lower sensations of rectal distension with filling. Most biofeedback sessions are 30 to 60 minutes every 1 to 2 weeks and duration is variable over 5 to 6 sessions depending on patient progress. Contraindications to biofeedback therapy include impaired mobility or cognition, pregnancy, active rectal inflammation or anal fissure, as well as skepticism of its utility as this has also been shown to predict suboptimal outcomes. Overall, 70% of patients will respond to biofeedback therapy and bowel management counseling.²² Often, patients with defecatory dysfunction may also have an epiphenomenon or coexistent slow transit constipation and diagnosis and treatments for those disorders may need to be combined with biofeedback.²³,²⁴

For further assessment and management of defecatory dysfunction that does not respond to anorectal biofeedback therapy, there may be a role for defecography for diagnostic purposes as well as the use of valium orally or as a suppository, transanal injection of botulinum toxin type A (BTX-A), and bilateral partial division of puborectalis for therapy.