Solitary rectal ulcer syndrome

Solitary rectal ulcer syndrome (SRUS) is a chronic, benign disorder characterized by the presence of an abnormality of the rectum in persons who have a long history of straining during defecation. It is a misnomer because only a third of patients have a solitary ulcer, and many have no ulcers at all.

Epidemiology

Only 35% of cases have a solitary ulcer of the rectal wall. 22% have multiple ulcers. 43% have no ulcers at all. It typically occurs in young adults, with a slightly increased female predilection.

Clinical presentation

Diagnosis is delayed in many cases because of its rarity, non-specific presentation and multifactorial nature. Major complaints include:

• feeling of "incomplete emptying of the rectum": tenesmus
• chronic constipation
• strenuous defecation
• rectal bleeding
• rectal mucus secretions
• non-specific pelvic pain

Pathology

Etiology

Two functional disorders of defecation have been recognized:

1. Rectal intussusception
2. Spastic pelvic floor syndrome

The rectal wall invaginates into the distal portion of the rectal lumen or the anal canal. Invagination of the rectal wall causes stretching of submucosal vessels, ischemia, and ulceration.

The rectal abnormality has specific histologic features:

• replacement of the lamina propria by fibroblasts
• marked thickening of the muscularis mucosae

A definitive diagnosis of the syndrome requires a rectal biopsy.

Radiographic features

Fluoroscopy

Barium enema

• findings on barium enema may be normal or non-specific, consisting of
  • thickened valve(s) of Houston
  • nodularity
  • rectal stricture
  • circular narrowing of distal rectum may be noted
  • ulcer is variably identified

Defecating proctogram ¹

• spastic pelvic floor syndrome: inability for the pelvic floor to relax during the straining phase
• mucosal or full thickness rectoanal intussusception

MRI

Thickening and edema of the mucosa and submucosa of the low and mid rectum, with no intermediate tumor signal tissue and no breach of the muscularis propria. MRI proctography may show abnormalities of the posterior compartment such as mucosal intussusception or full-thickness external prolapse, and dyssynergy ³. 

Treatment and prognosis

• dietary and behavioral modifications are especially effective in patients with mild to moderate symptoms and with an absence of significant mucosal prolapse
  • patient education
  • high fiber diet
  • bulk laxatives
  • avoidance of straining
  • regulation of toilet habits
  • cognitive behavioral therapy (CBT) to ameliorate psychosocial factors
• for resistant symptoms
  • more organized form of behavioral therapy, e.g. biofeedback therapy may be warranted
• advanced grade of rectal intussusception, extensive inflammation, established fibrosis and/or irreducible external prolapse:
  • botulinum toxin injection
  • surgery