The role of colonoscopy and CT colonography in patients presenting with symptoms of constipation

Constipation and colonoscopy

Constipation is a significant sociomedical problem, which can be caused by various reasons. In the diagnostic approach to patients with constipation, the following data are usually sufficient: History, complete physical examination (including rectal examination), and additional diagnostic tests. A colonoscopy is not a necessary diagnostic method for all patients with constipation. However, if patients have alarm symptoms/signs, that suggest an organic reason for constipation, a colonoscopy is necessary. The most important alarm symptoms/signs are age > 50 years, gastrointestinal bleeding, new-onset constipation, a palpable mass in the abdomen and rectum, weight loss, anemia, inflammatory bowel disease, and family history positive for colorectal cancer. Most endoscopists do not like to deal with patients with constipation. There are two reasons for this, namely the difficulty of endoscopy and the adequacy of preparation. Both are adversely affected by constipation. To improve the quality of colonoscopy in these patients, good examination techniques and often more extensive preparation are necessary. Good colonoscopy technique implies adequate psychological preparation of the patient, careful insertion of the endoscope with minimal insufflation, and early detection and resolution of loops. Bowel preparation for colonoscopy often requires prolonged preparation and sometimes the addition of other laxatives.

Effect of dose splitting of a low-volume bowel preparation macrogol-based solution on CT colonography tagging quality

Purpose

To compare examination quality and acceptability of three different low-volume bowel preparation regimens differing in scheduling of the oral administration of a Macrogol-based solution, in patients undergoing computed tomographic colonography (CTC). The secondary aim was to compare CTC quality according to anatomical and patient variables (dolichocolon, colonic diverticulosis, functional and secondary constipation).

Methods

One-hundred-eighty patients were randomized into one of three regimens where PEG was administered, respectively: in a single dose the day prior to (A), or in a fractionated dose 2 (B) and 3 days (C) before the examination. Two experienced radiologists evaluated fecal tagging (FT) density and homogeneity both qualitatively and quantitatively by assessing mean segment density (MSD) and relative standard deviation (RSD). Tolerance to the regimens and patient variables were also recorded.

Results

Compared to B and C, regimen A showed a lower percentage of segments with inadequate FT and a significantly higher median FT density and/or homogeneity scores as well as significantly higher MSD values in some colonic segments. No statistically significant differences were found in tolerance of the preparations. A higher number of inadequate segments were observed in patients with dolichocolon (p < 0.01) and secondary constipation (p < 0.01). Interobserver agreement was high for the assessment of both FT density (k = 0.887) and homogeneity (k = 0.852).

Conclusion

The best examination quality was obtained when PEG was administered the day before CTC in a single session. The presence of dolichocolon and secondary constipation represent a risk factor for the presence of inadequately tagged colonic segments.

Colon Capsule Endoscopy vs. CT Colonography Following Incomplete Colonoscopy: A Systematic Review with Meta-Analysis

Following incomplete colonoscopy (IC) patients often undergo computed tomography colonography (CTC), but colon capsule endoscopy (CCE) may be an alternative. We compared the completion rate, sensitivity and diagnostic yield for polyp detection from CCE and CTC following IC. A systematic literature search resulted in twenty-six studies. Extracted data included inter alia, complete/incomplete investigations and polyp findings. Pooled estimates of completion rates of CCE and CTC and complete colonic view rates (CCE reaching the most proximal point of IC) of CCE were calculated. Per patient diagnostic yields of CCE and CTC were calculated stratified by polyp sizes. CCE completion rate and complete colonic view rate were 76% (CI 95% 68-84%) and 90% (CI 95% 83-95%). CTC completion rate was 98% (CI 95% 96-100%). Diagnostic yields of CTC and CCE were 10% (CI 95% 7-15%) and 37% (CI 95% 30-43%) for any size, 13% (CI 95% 9-18%) and 21% (CI 95% 12-32%) for >5-mm and 4% (CI 95% 2-7%) and 9% (CI 95% 3-17%) for >9-mm polyps. No study performed a reference standard follow-up after CCE/CTC in individuals without findings, rendering sensitivity calculations unfeasible. The increased diagnostic yield of CCE could outweigh its slightly lower complete colonic view rate compared to the superior CTC completion rate. Hence, CCE following IC appears feasible for an introduction to clinical practice. Therefore, randomized studies investigating CCE and/or CTC following incomplete colonoscopy with a golden standard reference for the entire population enabling estimates for sensitivity and specificity are needed.

Colonoscopy in the very elderly

INTRODUCTION

Colonoscopy is the gold standard test for investigating lower gastrointestinal symptoms and is an important therapeutic tool for colonic polypectomy. This paper is aimed at the general physician and examines the role of colonoscopy in very elderly patients by exploring the particular risks in this population, the yield of colonoscopy and potential alternative investigations.

SOURCES OF DATA

Original research and review articles were identified through selective PubMed searches. Guidelines were identified through interrogation of national and international society websites in addition to PubMed searches.

AREAS OF AGREEMENT

Advanced age alone is not a reason to avoid investigation. The decision to perform colonoscopy in this population must take into account indication and yield, risks of the procedure and bowel preparation, physical fitness of the patient, potential alternative and the ability to consent. As a general rule, the principle of 'first doing no harm' should be applied and requires balancing of the risks of the procedure and preparation with the benefits of doing the test.

AREAS OF CONTROVERSY

There is no defined upper age limit at which colonoscopy is contraindicated, however; the National Health Service Bowel Cancer Screening Programme stops inviting patients for screening and surveillance colonoscopy at age 75.

GROWING POINTS AND AREAS TIMELY FOR DEVELOPING RESEARCH

The concepts of 'first do no harm' and shared decision-making are not new but are increasingly important, particularly in this patient group. It is crucial to provide patients with information about risks, benefits and alternative investigations to empower their decision-making.