There is an English proverb – “the older the fiddle, the sweeter the tune.” In the current issue of the Journal of Digestive Endoscopy, an article reminds me of this proverb.[1] In this study from southern India on a large number of patients (n = 9418) undergoing rigid sigmoidoscopic examination for bleeding per rectum (51%) and chronic constipation (21%) and sigmoidoscopic assessment of ulcerative colitis, the diagnostic yield of proctosigmoidoscopy was as high as 73.5%.[1] Although such a high yield of a limited sigmoidoscopic examination is quite encouraging, it does raise several issues, which are being discussed below.
Why is it encouraging? Although a full-length colonoscopy would be a better investigation than a limited examination of anorectum in some conditions, such as endoscopic assessment of ulcerative colitis, the former needs expertise, is not widely available, and is also quite expensive. Therefore, it is quite encouraging for the physicians working in a resource-constraint environment to know that even a limited examination of the anorectum with a rigid sigmoidoscope gave a diagnostic yield of 73.5%. However, the downside of such an approach includes missing more proximal lesions and failing to recognize the extent of ulcerative colitis, which has significant implication in the management and prognosis of the disease.[2] For example, a patient with proctosigmoiditis is better managed with 5-aminosalicylate enema alone, which is rather a suboptimal treatment in patients with pancolitis.[2] Some of the patients with inflammatory bowel disease, particularly Crohn’s disease, may have more proximal or skip lesions, which might have been missed by rigid sigmoidoscopy.[3] Similarly, in patients with colon cancer or polyp, the synchronous and metachronous proximal lesions would be missed.[4]
In the current series, the diagnostic yield of rigid sigmoidoscopy in patients with bleeding per rectum was very high to the tune of 98.5% of whom 72.7% had hemorrhoids.[1] This may suggest that in patients with bleeding per rectum, the rigid sigmoidoscopic examination is very useful. In fact, in practice, most of us working in big university hospitals have seen that patients with ulcerative colitis presenting with bleeding per rectum had surgery for piles, albeit inappropriately, in a community care setting, which could be obviated by a rigid sigmoidoscopic examination. Therefore, the result of this study has important clinical application.
Twenty-nine percent of patients underwent rigid sigmoidoscopy for chronic constipation. It is important to note that in patients with chronic constipation without alarm symptoms such as old age, visible or occult gastrointestinal (GI) bleed, family history of colon cancer, unintended weight loss, abdominal mass, and fever, even full-length colonoscopy may not yield much, and hence, the limited sigmoidoscopic examination is not worth it.[5]
26.5% of patients had a negative sigmoidoscopic examination.[1] However, were these true-negative results? Is it possible that a full-length colonoscopy might have yielded positive results in some of them? This would also depend on the indication of the sigmoidoscopic/colonoscopic examination. For example, some diseases such as Crohn’s disease tend to spare rectum, and hence, a limited sigmoidoscopic examination is expected to show a false-negative result.[3] In contrast, rigid sigmoidoscopy alone is expected to be sufficient to detect piles and solitary rectal ulcer.
Although the current single-center retrospective series of 9418 patients undergoing rigid sigmoidoscopic examination for lower GI diseases hardly adds much novel information, it does have important clinical implication.[1] In countries such as India with superspecialty healthcare facilities that are unlikely to match the vast and ever-growing population, simple, cheap, widely available technologies such as rigid sigmoidoscopy may diagnose several anorectal diseases that may be of great help for the treatment of these patients. In fact, the saying that “half a loaf is better than none” does apply here.
