About 40% of the population experiences lower GI symptoms suggestive of gastrointestinal motility disorders.1,2 The global prevalence of chronic constipation is 18%, and the condition includes multiple overlapping subtypes.3 Evacuation disorders affect over half (59%) of patients and include dyssynergic defecation (DD).4 The inability to coordinate the abdominal, rectal, pelvic floor, and anal/puborectalis muscles to evacuate stools causes DD.5 The etiology of DD remains unclear and is often misdiagnosed. Clinically, the symptoms of DD overlap with other lower GI disorders, often leading to unnecessary and invasive procedures.2 We describe the clinical characteristics, diagnostic tools, treatment options, and evidence-based approach for the management of DD.
Over two-thirds of patients with DD acquire this disorder during adulthood, and one-third have symptoms from childhood.6 Though there is not usually an inciting event, 29% of patients report that symptoms began after events such as pregnancy or back injury,6 and opioid users have higher prevalence and severity of DD.7
Over 80% of patients report excessive straining, feelings of incomplete evacuation, and hard stools, and 50% report sensation of anal blockage or use of digital maneuvers.2 Other symptoms include infrequent bowel movements, abdominal pain, anal pain, and stool leakage.2 Evaluation of DD includes obtaining a detailed history utilizing the Bristol Stool Form Scale;8 however, patients’ recall of stool habit is often inaccurate, which results in suboptimal care.9,10 Prospective stool diaries can help to provide more objective assessment of patients’ symptoms, eliminate recall bias, and provide more reliable information. Several useful questionnaires are available for clinical and research purposes to characterize lower-GI symptoms, including the Constipation Scoring System,11 Patient Assessment of Constipation Symptoms (PAC-SYM),12 and Patient Assessment of Constipation Quality of Life (PAC-QOL).2,13 The Constipation Stool digital app enhances accuracy of data capture and offers a reliable and user-friendly method for recording bowel symptoms for patients, clinicians, and clinical investigators.14
The diagnosis of DD requires careful physical and digital rectal examination together with anorectal manometry and a balloon expulsion test. Defecography and colonic transit studies provide additional assessment.
Abdominal examination should include palpation for stool in the colon and identification of abdominal mass or fecal impaction.2A high-quality digital rectal examination can help to identify patients who could benefit from physiological testing to confirm and treat DD.15 Rectal examination is performed by placing examiner’s lubricated gloved right index finger in a patient’s rectum, with the examiner’s left hand on patient’s abdomen, and asking the patient to push and bear down as if defecating.15 The contraction of the abdominal muscles is felt using the left hand, while the anal sphincter relaxation and degree of perineal descent are felt using the right-hand index finger.15 A diagnosis of dyssynergia is suspected if the digital rectal examination reveals two or more of the following abnormalities: inability to contract abdominal muscles (lack of push effort), inability to relax or paradoxical contraction of the anal sphincter and/or puborectalis, or absence of perineal descent.15 Digital rectal examination has good sensitivity (75%), specificity (87%), and positive predictive value (97%) for DD.16