Acute Surgical Abdomen in Collagenous Colitis

The most striking aspect of the case report by Bennett and colleagues is the clear pathologic demonstration of an entirely benign colonic perforation in the mucosa that showed typical histopathologic features of collagenous colitis.¹ The features of collagenous colitis have been reviewed elsewhere.²

Our understanding of the long-term natural history of collagenous colitis has grown over the nearly 40 years since the disorder was first described in January 1976 by both Canadian and Swedish researchers in separate studies.^3,4 In the Canadian report by Freeman and colleagues,³ a distinctive pathologic mucosal lesion was first noted in 2 women who were experiencing watery diarrhea.³ The presence of collagen was suspected on routine light microscopic evaluation and special histochemical studies. Electron microscopic studies of the colonic mucosal biopsies confirmed the ultrastructural presence of collagen fibers.

In the Swedish case report by Lindstrom and colleagues, which involved a woman who was experiencing watery diarrhea, light microscopic findings of the presence of collagen also were independently confirmed.⁴ At a much later date, ultrastructural changes similar to those seen in the Canadian case were independently confirmed.⁵

Large clinical survey series, mainly from Scandinavian centers, subsequently demonstrated that middle-aged and elderly women were the population most at risk for collagenous colitis.^6,7 The disorder usually has a benign clinical course, at least during an evaluation period of about 10 years.⁸ In most cases, persistent diarrhea develops; otherwise, intermittent periods of recurrent diarrhea develop. Spontaneous resolution has been recorded, making it difficult to evaluate responsiveness to different forms of treatment. Because the characteristic subepithelial collagen deposits may be patchy and variable in depth or they may be focal rather than diffuse and continuous in some parts of the colonic mucosa, a histologic endpoint regarding subepithelial collagen deposits has been difficult to estimate when designing clinical trials. Treatment has been focused largely on symptom resolution with high-fiber diets, nonspecific antidiarrheal agents, and antiinflammatory agents, particularly the 5-aminosalicylate class of medications. Corticosteroids, such as delayedrelease budesonide, also may provide symptomatic relief² Other agents, including immunosuppressive agents and biologics, have been empirically used.

In recent years, the relationship between collagenous colitis and other disorders has been explored. Other immune-mediated diseases have been closely linked to collagenous colitis, including arthritis, spondylitis, thyroiditis, and some dermatologic disorders, including pyoderma gangrenosum.² Other gastrointestinal disorders also may develop. Celiac disease, for example, has been detected in about 20% of patients.⁹ Moreover, in some cases of collagenous colitis, inflammatory mucosal disease marked by collagen deposits may be detected elsewhere in the gastrointestinal tract, including the stomach and small bowel, suggesting that collagenous colitis may be a very heterogeneous disorder.¹⁰ Interestingly, it is uncommon to see malignant colonic complications in the clinical course of collagenous colitis,¹¹ but the associated malignancies have included adenocarcinoma, lymphoma, and neuroendocrine neoplastic disease, specifically carcinoids.^12,13

Although collagenous colitis has a benign and sometimes relapsing and remitting course in most patients, some serious complications can occur. Rarely, a severe and protracted course may be seen, and, in at least one report, a fatal outcome was attributed directly to the colitis.¹⁴ In some patients, a prominent histologic feature of surface epithelial cell sloughing may be detected, providing visual evidence of enhanced mucosal permeability and protein-losing enteropathy.¹⁵ Colonic ulceration may occur and is possibly related to concomitant use of medications, particularly nonsteroidal anti-inflammatory drugs.¹⁶ Rarely, collagenous colitis may progress to inflammatory bowel disease. In one report of collagenous colitis that progressed to severe ulcerative colitis and necessitated colectomy, complete disappearance of preexistent collagen deposits in the resected colon was noted.¹⁷

Other serious colonic complications have been recorded. As in the report by Bennett and colleagues,¹ spontaneous peritonitis with colonic perforation has been previously noted.¹⁸ Peritonitis with colonic perforation is perhaps related to colonic wall compromise that is associated with submucosal collagen deposition. Submucosal dissection has been described.¹⁹ In some cases, changes related to investigative procedures, particularly endoscopic instrumentation possibly due to air insufflation and barotraumas, have been described, and the term “colonic fracturing” has emerged.²⁰ Indeed, endoscopists noting these changes during colonoscopic evaluation might be advised to maintain close observation of patients following colonoscopy.

In summary, a variety of clinical presentations for collagenous colitis have become increasingly recognized. Although chronic or recurrent nonbloody diarrhea is most common, collagenous colitis may initially present with or be complicated by serious findings, including an acute surgical abdomen, which requires urgent surgical treatment. In this situation, an acute colonic perforation deserves special diagnostic attention, especially if the perforation developed following colonoscopic evaluation or in a patient with known collagenous colitis.