Anorectal Dysfunction in Distal Ulcerative Colitis: Challenges and Opportunities for Topical Therapy

We read with interest the intriguing report on rectal hypersensitivity in quiescent ulcerative colitis [UC] by Casanova and colleagues.¹ Anorectal dysfunction causing urgency, tenesmus, and incontinence are particularly distressing symptoms of dysmotility in UC, which, although most pronounced during active disease, are often present in quiescent and long-standing disease. Reduced rectal wall compliance, and the resultant increased stiffness and rectal narrowing with widening of the pre-sacral space secondary to proliferation of peri-rectal fat, are other possible reasons for such symptoms in the absence of inflammation.² Furthermore, reduced maximal tolerable balloon volume [as a measure of rectal sensitivity] has been observed in active colitis, with pain reported at lower cross-sectional areas of the rectum compared with healthy individuals. This is likely to be due to increased muscle tone, given that pain response relative to muscle tension is similar in patients and healthy controls.² Neuroplasticity and its fundamental role in the aberrant dysmotility, sensation, and secretion associated with gastrointestinal inflammation [both during and after], represent areas of serious research potential and major unmet therapeutic need.

The very pathophysiological processes that drive symptoms during disease quiescence are, however, exaggerated during active distal disease, and patients may suffer significant morbidity and poor quality of life from symptoms such as urgency, tenesmus, and bleeding per anum. Patients with ulcerative proctitis often describe frequent bloody bowel movements, but these do not represent ‘true’ diarrhoea, a concept not widely appreciated by non-IBD specialists, often leading to potentially premature treatment ‘escalation’ and prolonged, futile exposure to corticosteroid therapy, and under-use of rectal therapies.³ Physicians have a lower threshold to anticipating poor acceptability of topical therapy despite evidence supporting good acceptance by > 80% of patients.⁴ It is plausible that patients vary in their tolerance to larger-volume enemas, especially in the context of inflammation with reduced rectal compliance and hypersensitivity.³ Recent studies reporting better tolerance of smaller-volume [25 ml] foam over 100-ml liquid enemas with high adherence [> 94%] over a 6-week period suggest that foam enemas which deliver a drug over the same anatomical extent as a liquid enema may be better tolerated, but also that tolerance depends on volume, and spread on viscosity.⁵

Topical rectal therapies may arguably be less appealing to healthcare professionals than patients, and physician education may be as important as understanding patient preference, cultural influences on beliefs, and indeed formulations themselves. Mild to moderate distal UC is often treated in primary care or in liaison with inflammatory bowel disease [IBD] clinical teams. This underpins the need for a patient-centred collaborative approach with healthcare professionals improving their own and their patients’ understanding and acceptance of potentially effective topical therapies, avoiding premature escalation of treatment.

Conflict of Interest

The authors have no conflicts of interest to declare.

Author Contributions

Both authors reviewed the literature and co-wrote the manuscript.