Chapter 32 - Dyssynergic defecation and defecation disorders

Abstract

Evacuation disorders are common and affect up to one half of patients with chronic constipation. These disorders are a consequence of either functional or structural abnormalities such as an inability to coordinate the abdominal and pelvic floor muscles to evacuate stools or internal mucosal intussusception or rectal prolapse. Dyssynergic defecation (DD) is an acquired behavioral functional disorder of incordinated defecation that requires a comprehensive approach including a detailed history, a careful digital rectal examination and anorectal physiological tests. Anorectal manometry and balloon expulsion test are essential for its diagnosis. Newer techniques such as high-resolution manometry and magnetic resonance defecography can provide more detailed mechanistic insights. Biofeedback therapy is considered the mainstay of treatment for DD and has been confired in 5 Randomized Controlled Trials. Solitary rectal ulcer syndrome (SRUS) is characterized by the presence of either single or multiple ulcerations of the rectum and is associated with DD in up to 80% of patients. Other structural abnormalities that might induce anorectal symptoms included rectal mucosal intussusception, descending perineum syndrome and rectal prolapse. Here, we provide a comprehensive overview regarding the pathophysiology, and how to diagnose and treat these common anorectal disorders.