Don C. Rockey

Asymptomatic chronic gastrointestinal blood loss in patients taking aspirin or warfarin for cardiovascular disease.

OBJECTIVE To determine whether low-dose aspirin or warfarin induces fecal occult blood loss. PATIENTS AND METHODS A prospective, cross-over study, of 100 participants over 40 years of age in 1 of 3 groups, taking: (1) no aspirin or warfarin, (2) daily aspirin (either 81 or 325 mg), or (3) warfarin, but no aspirin. Stool samples were collected and analyzed for the presence of occult blood using HemoQuant and Hemoccult II. After collection of baseline samples, patients initially taking no aspirin (group 1) were asked to take regular aspirin (325 mg daily) for 2 months. Patients initially taking aspirin 81 mg daily (group 2) were switched to 325 mg daily for 2 months, and vice versa. RESULTS Patients taking no aspirin had mean fecal blood of 0.68 +/- 0.05 mg hemoglobin/g stool, which increased to 1.41 +/- 0.36 mg/g after taking 325 mg of aspirin daily (P = 0.02). In contrast, patients in group 2, taking 81 mg and 325 mg of aspirin, had mean fecal blood of 0.82 +/- 0.08 mg/g (P = 0.57) and 1.04 +/- 0.23 mg/g (P = 0.13), respectively (comparisons with patients taking no aspirin). The mean blood loss in patients taking warfarin was 0.51 +/- 0.04 mg/g (P = 0.55), and fecal blood was not related to the degree of anticoagulation. There was no increase over normal in the rate of Hemoccult II-positive stool tests with aspirin or warfarin therapy. CONCLUSION Aspirin, but not warfarin, caused a small but clinically insignificant increase in occult fecal blood. The small blood loss in patients taking aspirin or warfarin is unlikely to interfere with fecal occult blood test. Therefore, positive fecal occult blood tests, in patients taking either low-dose aspirin or warfarin, should be managed in the same fashion as patients not taking these medications.

The outpatient evaluation of hematochezia

Objective:The objective of this study was to determine whether specific clinical symptoms associated with hematochezia are predictive of important GI pathology and whether full colonoscopic examination is necessary.Methods:A total of 103 outpatients (⩽ 45 yr) with hematochezia, defined as the passage of bright red blood per rectum, underwent anoscopy and colonoscopy. Before endoscopy, patients completed a detailed interview, quantitating the amount and frequency of bleeding, weight loss, use of aspirin/NSAIDs, change in bowel habits, family history, and prior GI illnesses. Based on this information, physicians were asked to predict whether the bleeding was from a perianal or more proximal site. At colonoscopy, pathology was stratified as either proximal or distal to the sigmoid/descending junction. Substantial pathology was defined as one or more adenomas > 8 mm, carcinoma, or colitis.Results:Anoscopy demonstrated internal and external hemorrhoids in 78 and 29 patients, respectively. On colonoscopy, 36 patients had 43 substantial lesions. Thirty-seven of these lesions were distal to the junction of the descending and sigmoid colons and six were proximal lesions. Four patients had cancer; all were distal lesions. Patients with substantial lesions were more likely to give a history of blood mixed within their stool (p = 0.03), to have more episodes of hematochezia per month (p = 0.008), and to have a significantly shorter duration of bleeding before medical evaluation (p = 0.02) than did patients without such lesions. However, the physicians clinical assessment did not predict reliably which patients were likely to have substantial pathology.Conclusions:In patients with hematochezia, clinicians were unable to distinguish between those patients with and those without significant colonic lesions by history alone. Flexible sigmoidoscopy would have demonstrated most (95%) substantial lesions. The lesions that flexible sigmoidoscopy missed were an unlikely cause of bleeding in this small group of patients.

Prospective comparison of air-contrast barium enema and colonoscopy in patients with fecal occult blood: a pilot study

BACKGROUND The utility of air-contrast barium enema and colonoscopy for evaluation of the colon has been debated. Air-contrast barium enema is less expensive and invasive than colonoscopy, but it also is less sensitive and specific. Further, although air-contrast barium enema may be less painful than colonoscopy, it often is poorly tolerated by patients. Thus, this study compared the sensitivity and the specificity of air-contrast barium enema and colonoscopy for detection of colonic lesions in patients with fecal occult blood. METHODS Over a 30-month period, patients with fecal occult blood were recruited. Patients underwent standard air-contrast barium enema, followed by colonoscopy 7 to 14 days later. Colonoscopists were blinded to the results of air-contrast barium enema until the colonoscopy was completed, after which the results were disclosed. If the findings were discrepant, colonoscopy was repeated. RESULTS A total of 100 patients were evaluated. Nine air-contrast barium enemas were reported to be inadequate, and the cecum was not intubated at colonoscopy in two patients. In the remaining patients, 5 cancers were identified (1 each cecum, transverse colon, descending colon, sigmoid colon, and rectum) by both studies. Sixty-six polypoid lesions were identified in 30 patients. Diverticula were identified in 42 patients by air-contrast barium enema and in 18 patients by colonoscopy. Air-contrast barium enema detected 3 of 36 polypoid lesions 5 mm or less in diameter, 5 of 15 adenomas 6 to 9 mm in size, and 4 of 15 adenomas 10 mm or greater in diameter (sensitivity 8%, 33%, and 27%, respectively). After excluding patients with diverticula, air-contrast barium enema detected 3 of 7 adenomas 10 mm or greater in size. Overall, 12 polypoid lesions or filling defects were identified by air-contrast barium enema that could not be verified by colonoscopy. The specificity of air-contrast barium enema for lesions 1.0 cm or greater in size was 100%; for those 6 mm or greater, it was 97%. CONCLUSIONS Air-contrast barium enema accurately detects colon cancer and diverticula. Its sensitivity for detection of polypoid lesions or adenomas is poor and was confounded by the presence of diverticula.