Dyssynergic Defecation: A Comprehensive Review on Diagnosis and Management

Abstract

About one-third of chronically constipated patients have an evacuation disorder, and dyssynergic defecation is a common cause of the evacuation disorder. In dyssynergic defecation, the coordination between abdominal and pelvic floor muscles during defecation is disrupted and patients cannot produce a normal bowel movement. The etiology of dyssynergic defecation is still unknown. Although a detailed history taking and a careful examination including digital rectal examination could be useful, other modalities such as anorectal manometry and balloon expulsion test are necessary for the diagnosis. Biofeedback therapy is one of the most effective and safe treatments. Here, we provide an overview of dyssynergic defecation as well as how to diagnose and manage this condition.

Figure 1.

The 4 types of dyssynergic defecation according to anorectal manometry. Type 1 with adequate propulsive pressure more than or equal 40 mmHg and a paradoxical increase anal pressure. Type 2 with inadequate propulsive pressure less than 40 mmHg with a paradoxical increase anal pressure. Type 3 with adequate propulsive pressure more than or equal 40 mmHg and impaired anal relaxation less than or equal 20 mmHg. Type 4 with inadequate propulsive pressure less than 40 mmHg and impaired anal relaxation less than or equal 20 mmHg.

Figure 2.

Manometry of a patient with dyssynergic defecation during push period. Intra-rectal pressure did not increased when anal pressure significantly raised (compatible with type 2).

Figure 3.

Proposed clinical pathway. R/O, rule out; BET, balloon expulsion test; ARM, anorectal manometry; MR Defecography, magnetic resonance defecography; DD, dyssynergic defecation; CTT, colon transit time; EMG/NCV, electromyography and nerve conduction study.