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Diversion colitis was first described by Morson et al. in 1974, as a non-specific inflammation of the diverted colon. Glotzer et al. coined the term “diversion colitis” in 1981. Since then, this entity has been described in both retrospective and prospective studies, describing clinical, endoscopic and histopathological findings. The absence of pathognomonic features makes it difficult to differentiate from other entities, such as active inflammatory bowel disease.
Pathophysiology
The basic underlying mechanisms are still unclear. A change in luminal flora due to fecal stream interruption is possibly the culprit. Normal bacteria produce short chain fatty acids, such as butyric acid. Butyrate is the main oxidative substrate for colonocytes and has an effect in relaxing vascular smooth muscles. A SCFA depletion can possibly lead to colonic ischemia and inflammation through this mechanism.
Treatment Strategies
1. Surgery
Gut continuity is the only curative strategy. Even though it can present with severe inflammation, colonic resection is not usually required, and fecal stream restoration can be sufficient to reverse it.
2. SCFA
Topical treatment with butyrate enemas has been proven effective, as SCFA provides an exogenous source of nitric oxide that has a vasodilatory effect. Harig et al. reported clinical and endoscopic remission of diversion colitis with SCFA enemas in four patients in 1989. Since then, several other studies have shown inconsistent results.
3. Steroids
Corticosteroids are first-line agents for symptomatic diversion colitis. Hydrocortisone via daily enema can generate a response in 3-5 days and this treatment should be maintained for up to three weeks.
4. ASA
Usefulness of 5-aminosalicylic acid enemas in diversion colitis was first reported by Triantafillidis et al. in 1991. 5-ASA may seem to reduce oxidative DNA damage in colonic cells, reducing inflammation.
5. Immune therapy
Considering the similarities of diversion colitis with inflammatory bowel disease, anti-TNF agents have been considered as a treatment strategy. Pro-inflammatory cytokines are produced by neutrophils in the colonic mucosa. This is where a potent anti-inflammatory agent such as infliximab may play a role.
6. Fecal Microbiome Transplantation
Fecal transplantation consists in transferring stool from a healthy donor to the patient’s colon and is an effective treatment for some diseases, ie. Recurrent Clostridium difficile infections and Crohn’s disease. This therapy responds to the theory that diversion colitis is based on fecal stream interruption and offers an alternative to surgery when it is not possible.