Pelvic Floor Dyssynergia

Pelvic floor dyssynergia (dyssynergic defecation) is an acquired behavioural disorder of defecation in which the puborectalis and external anal sphincter contract or fail to relax during attempted evacuation, often with inadequate rectal propulsive force.

• It accounts for 25 to 50 percent of patients with chronic constipation in tertiary care and affects women more than men.
• Risk factors: childbirth injury, anorectal pain, previous anal surgery or trauma, abuse history, chronic straining behaviour learned in childhood, spinal cord and neurological disease, Parkinson disease.
• Three patterns: paradoxical contraction, inadequate relaxation, and inadequate propulsion.

Excessive straining, incomplete evacuation, digital manoeuvres, repeated toilet visits, passage of hard or soft stool, abdominal bloating, rectal pain.

• Digital rectal examination shows a high resting tone and a paradoxical tightening or failure of relaxation when the patient bears down.
• Differential diagnosis: slow transit constipation, rectocele, rectal prolapse, intussusception, Hirschsprung disease, anal stenosis, rectal tumour, proctalgia, cauda equina compression.
• Complications: haemorrhoids, fissure, solitary rectal ulcer, faecal impaction with overflow incontinence, rectal prolapse and psychological distress.

Diagnosis requires symptoms of outlet obstruction plus at least two abnormal tests: dyssynergic pattern on anorectal manometry or electromyography, abnormal balloon expulsion test (more than 1 minute), and delayed defecography evacuation or inadequate rectal propulsion.

• High resolution anorectal manometry, rectal sensation testing (barostat or balloon).
• Defecography for associated structural abnormalities; transit test for associated slow transit.
• Colonoscopy if alarm features; exclude hypothyroidism and hypercalcaemia.

Supportive: toilet posture with feet raised, abdominal wall relaxation, diaphragmatic breathing, no straining beyond 5 minutes, fibre 25 to 30 g daily, fluids.

Pharmacological

• Macrogol 17 g once or twice daily or lactulose 15 to 30 mL twice daily; glycerol 4 g suppository or bisacodyl 10 mg suppository before toilet attempts.
• Botulinum toxin A 50 to 100 units into the puborectalis under electromyographic or ultrasound guidance for refractory cases (temporary, risk of incontinence).
• Avoid chronic stimulant laxative overuse.

Procedures

• Biofeedback therapy using anorectal manometry or electromyography with simulated defecation training, rectal balloon training and abdominal pushing coordination: 6 to 8 sessions of 30 to 60 minutes every 1 to 2 weeks (success above 70 percent) is the main treatment.
• Home biofeedback devices for reinforcement.
• Sacral nerve stimulation or surgery only for selected structural problems.

Special groups: pregnancy (conservative care), elderly (exclude impaction), neurogenic bowel (programmed bowel regimen).

Red flags: rectal bleeding, weight loss, new neurological signs, onset after age 50 years, severe pain.

Follow-up: assess stool diary at 4 to 6 weeks; repeat manometry if relapse; continue home exercises.