Overview

Pelvic floor muscle dyssynergy, also known as dyssynergic defecation, is a functional bowel disorder that causes chronic constipation due to poor coordination of the pelvic floor and anal sphincter muscles. Instead of relaxing during a bowel movement, these muscles may contract or fail to relax adequately, making it difficult to pass stool or fully empty the rectum.

This condition is not caused by a physical blockage but by an abnormal learned pattern of muscle activity. It is a common and often underdiagnosed cause of chronic constipation, affecting both men and women. The most effective treatment is pelvic floor retraining through biofeedback therapy, which helps restore normal muscle coordination and significantly improves bowel function in many patients.

What Is Pelvic Floor Muscle Dyssynergy?

Pelvic floor muscle dyssynergy, also known as dyssynergic defecation, is a common cause of chronic constipation. It occurs when the muscles of the pelvic floor and anal sphincter do not coordinate properly during a bowel movement.

Normally, these muscles relax to allow stool to pass. In pelvic floor dyssynergia, the muscles may tighten instead of relax, or may not relax sufficiently, making it difficult to fully empty the bowels.

This condition is not caused by a structural blockage, but rather by a learned pattern of muscle dysfunction. It is estimated to affect up to 50% of patients with chronic constipation and occurs in both women and men.

What Causes Dyssynergic Defecation?

Dyssynergic defecation develops over time and is often related to behavioral and functional patterns.

Common contributing factors include:

• Repeatedly ignoring the urge to have a bowel movement
• Painful bowel movements leading to avoidance
• Chronic constipation with straining
• Prior pelvic floor dysfunction or injury

Over time, these patterns can retrain the body to use the wrong muscle coordination during defecation. In women, pelvic floor dysfunction may also be associated with pregnancy, vaginal delivery, pelvic organ prolapse, or hormonal changes. In men, it is more commonly associated with long-standing constipation, chronic straining, or prior anorectal conditions.

What Are the Signs and Symptoms of Dyssynergic Defecation?

Symptoms can vary but commonly include:

• Chronic constipation that does not respond to fiber or laxatives
• Excessive straining during bowel movements
• Sensation of incomplete evacuation
• Need for manual maneuvers to assist defecation
• Hard stools or infrequent bowel movements

These symptoms are often mistaken for routine constipation, and many patients remain undiagnosed despite ongoing symptoms.

How Is Pelvic Floor Dyssynergia Diagnosed?

Diagnosis requires a combination of clinical assessment and specialized testing.

A detailed history, prospective stool diaries, and careful digital rectal examination can raise suspicion for this disorder.

Essential diagnostic tests include:

• Anorectal manometry: This test measures how well the muscles in the rectum and anus are working together. It helps show whether the muscles relax and tighten at the right times during a simulated bowel movement.
• Defecography (MRI): This imaging study assesses how the pelvic floor and rectum function during defecation and can identify abnormal muscle patterns or structural contributors.

How Is Dyssynergic Defecation Treated?

Treatment focuses on retraining the muscles so they work together properly during bowel movements.

• Pelvic floor physical therapy (biofeedback): This is the most effective treatment. A specially trained therapist helps you learn how to relax and coordinate the pelvic floor muscles during defecation.
• Bowel habit training: Learning healthy bathroom habits, including responding to the urge to go and proper positioning on the toilet, can make bowel movements easier.
• Diet and stool management: Fiber, fluids, and stool-softening medications may be recommended to reduce straining and make stools easier to pass.
• Medications: Laxatives or other medications may be used to help stool consistency but are usually combined with pelvic floor therapy for best results.

With proper treatment, many patients experience significant improvement in symptoms and quality of life.

Who Should Be Evaluated?

Patients with chronic constipation that does not respond to standard treatments, particularly those with a persistent sensation of incomplete evacuation or difficulty passing stool, should be considered for evaluation for pelvic floor dyssynergia.

Pelvic floor disorders affect both women and men. While certain risk factors differ (such as pregnancy and childbirth in women) many of the underlying mechanisms and symptoms are similar for both men and women alike.

Evaluation by a gastroenterologist experienced in pelvic floor disorders can help guide appropriate, targeted treatment.