Best Initial Investigation for Sigmoid Ulcer with Ascending Colon Polyps
Colonoscopy is the best initial investigation for a patient with a sigmoid ulcer and ascending colon polyps, as it allows complete visualization of the entire colon, tissue sampling from both lesions, and therapeutic intervention in a single session. 1
Why Colonoscopy is Superior
Complete colonic evaluation is essential when pathology exists in both the sigmoid colon (ulcer) and ascending colon (polyps), as these lesions are separated by significant distance and require different diagnostic considerations. 1
Colonoscopy allows direct mucosal inspection of the entire colon from the appendiceal orifice to the dentate line with same-session biopsy sampling and definitive treatment by polypectomy. 1
The procedure can establish diagnosis in more than 90% of cases when evaluating colonic pathology, making it the diagnostic procedure of choice. 1
Colonoscopy enables histological confirmation through biopsies from multiple sites, which is essential for differentiating between inflammatory, infectious, ischemic, and neoplastic etiologies. 1
Why Flexible Sigmoidoscopy is Inadequate
Flexible sigmoidoscopy cannot adequately evaluate this clinical scenario because it only examines the rectum, sigmoid, and descending colon under optimal conditions (typically to 40-60 cm). 1
The ascending colon polyps lie beyond the reach of even extended flexible sigmoidoscopy, which achieves cecal intubation in only 32% of patients. 2
When adenomatous polyps are detected during sigmoidoscopy, colonoscopy is mandated anyway to evaluate for proximal lesions, as 34% of patients with distal adenomas harbor additional proximal adenomatous polyps. 1, 3
Studies demonstrate that 80% of significant lesions are beyond the reach of standard sigmoidoscopy, and the second highest percentage of lesions are found in the ascending colon. 4
Critical Diagnostic Considerations for the Sigmoid Ulcer
The sigmoid ulcer requires tissue diagnosis to differentiate multiple etiologies:
Ischemic colitis presents with sharply defined segments particularly in the "watershed territory" from sigmoid colon to splenic flexure, with longitudinal ulcerations. 1
Inflammatory bowel disease (Crohn's disease or ulcerative colitis) shows discrete ulcers, longitudinal or aphthous ulcers, and cobblestone appearance favoring Crohn's. 1
Intestinal tuberculosis demonstrates transverse ulcers, patulous ileocecal valve, and localized involvement. 1
Infectious colitis accounts for 38% of acute hemorrhagic colitis presentations and requires endoscopic evaluation with biopsy since stool cultures are positive in only 40-60% of cases. 1
Management of the Ascending Colon Polyps
The ascending colon polyps require complete evaluation and removal:
Any adenomatous polyp detected necessitates total colon examination to identify synchronous lesions, as 14-34% of patients have additional polyps beyond the initially detected lesion. 4, 3
Colonoscopy allows same-session polypectomy with proper margin assessment, which is critical for determining adequacy of excision and risk of lymph node metastasis in malignant polyps. 1
The entire polyp should be removed intact when possible to allow optimal pathologic sectioning through the center of the stalk for margin evaluation. 1
Common Pitfalls to Avoid
Do not perform sigmoidoscopy first in this scenario, as it will inevitably require subsequent colonoscopy, subjecting the patient to two procedures instead of one. 5
Do not rely on barium enema as the initial test, as 24 of 89 patients (27%) in one study required subsequent colonoscopy after barium enema for suspected tumors, polyps, incomplete examination, or unexplained bleeding. 5
Ensure adequate bowel preparation as proper preparation is critical for accuracy and cost-effectiveness of colonoscopy. 1
Obtain biopsies from the sigmoid ulcer from at least one site to establish diagnosis and exclude infectious or inflammatory etiologies. 1