Table 1.
Indications for ARM as a Diagnostic Test, Prevalence of These Disorders, and Sensorimotor Abnormalities That May Be Detected in Each Condition
| Condition | Prevalence Estimate | Findings of ARM and Anorectal Function Tests5,12,15,61 |
|---|---|---|
| Fecal incontinence | Fecal incontinence is experienced by 14.4% of Americans and 18.8% of women.7,8 | • Weak resting pressure suggests sphincter weakness • Weak squeeze pressure suggests sphincter weakness • Abnormal cough reflex suggests neuropathy or spinal cord injury • Rectal hyposensitivity or rectal hypersensitivity • Impaired rectal compliance • Lumbar and sacral plexus neuropathy |
| Constipation | In In a large-scale multinational study using Rome IV diagnostic criteria, functional bowel disorders were most common and functional constipation was the most prevalent bowel disorder, affecting nearly 9% of the U.S. population.9 | • Hypertonic resting sphincter pressure • Abnormal rectoanal inhibitory reflex suggests Hirshsprungs disease • Rectal hyposensitivity or rectal hypersensitivity • Prolonged balloon expulsion time |
| Rectal sensory disorder | Rectal sensory disorders can affect 4%— 19% of fecal incontinence patients (rates vary by sex).10 | • Rectal hyposensitivity • Rectal hypersensitivity |
| Dyssynergic defecation | Prevalence of dyssynergic defecation in the general population is unknown.11 Dyssynergic defecation affects between one-third to one-half of constipated patients referred for anorectal testing.12–14 | • Hypertonic resting pressure • Abnormal defecation patterns, type I—IV dyssynergia • Rectal hyposensitivity or hypersensitivity • Prolonged balloon expulsion time |
| Descending perineum syndrome | Descending perineum syndrome is seen in 7.7% of constipated patients.15 | • Excessive perineal descent • Rectal mucosal intussusception • Weak resting pressure • Weak squeeze pressure • Dyssynergic defecation • Prolonged balloon expulsion time |
| Anorectal pain | The prevalence of functional anorectal pain, levator ani syndrome, and proctalgia fugax is estimated to be 11.3%, 6.0%, and 7.9%, respectively.16 | • Weak resting pressure • Weak squeeze pressure • Rectal sensation abnormality • Hypertonic anal sphincter • Lumbar and sacral plexus neuropathy |
| Rectal prolapse | Estimates of rectal prolapse are low (<0.5%).17 | • Rectal mucosal intussusception or prolapse • Rectal hypersensitivity • Weak resting pressure |
ARM, anorectal manometry.