Diagnosis and Management of Defecatory Disorders

Introduction to Defecatory Disorders

• The American Gastroenterological Association notes that patients with daily bowel movements can still have constipation, and reduced stool frequency is poorly correlated with delayed colonic transit 1
• The sensation of incomplete evacuation is 84% sensitive and 54% specific for defecatory disorders, making this a key diagnostic feature 2

Pathophysiology of Defecatory Disorders

• Defecatory disorders are characterized by impaired rectal evacuation from inadequate rectal propulsive forces and/or increased resistance to evacuation 1
• Paradoxical contraction or incomplete relaxation of the pelvic floor and external anal sphincters during defecation (dyssynergia) can result in defecatory disorders 1
• High anal resting pressure ("anismus") and reduced rectal sensation may coexist with the muscular dysfunction 1

Diagnostic Approach for Defecatory Disorders

• The American Gastroenterological Association recommends proceeding to anorectal manometry and balloon expulsion testing in patients who fail empiric laxative trials 2
• These tests can identify inadequate rectal propulsive forces, paradoxical pelvic floor contraction (dyssynergia), incomplete anal sphincter relaxation, and reduced rectal sensation 2

Treatment of Defecatory Disorders

• Pelvic floor biofeedback therapy is the treatment of choice for defecatory disorders, improving symptoms in more than 70% of patients with dyssynergic defecation 2
• Biofeedback involves retraining coordination of abdominal, rectal, and pelvic floor muscles during defecation and includes sensory retraining for patients with rectal hyposensitivity 2

Rationale for Treatment Choices

• Fiber supplementation alone does not improve other parameters of defecation (stool consistency, straining effort, pain on defecation, or completeness of evacuation) in defecatory disorders 3, 4
• Magnesium citrate and probiotics address colonic transit, not pelvic floor coordination 3, 4, 5
• The American Gastroenterological Association strongly recommends polyethylene glycol (PEG) 17g daily as the first-line osmotic laxative with better evidence 2