Treatment Approach for Sigmoid Colitis
Immediate Assessment and Risk Stratification
The treatment of sigmoid colitis depends critically on distinguishing between inflammatory bowel disease (ulcerative colitis), infectious colitis, and ischemic colitis, followed by rapid assessment for life-threatening complications requiring emergency surgery. 1
Initial Evaluation Must Include:
Immediate hospitalization for patients meeting criteria for severe colitis (≥6 bloody stools daily, tachycardia >90 bpm, temperature >37.8°C, hemoglobin <10.5 g/dL, or ESR >30 mm/hr) to prevent delayed decision-making that increases perioperative morbidity and mortality 1
Full blood count, inflammatory markers (CRP or ESR), electrolytes, liver function tests, and stool culture with C. difficile toxin assay at admission for acute severe presentations 1
Plain abdominal radiograph to exclude colonic dilatation (≥5.5 cm) and assess disease extent, as mucosal islands or >2 gas-filled small bowel loops predict poor response to medical treatment 1
CT imaging with IV contrast when diagnosis is uncertain or to evaluate for ischemia, though this should not delay surgery in unstable patients 2, 3
Emergency Surgical Indications (Immediate Surgery Required)
Surgery is mandatory and must not be delayed in the following scenarios:
Perforation with peritoneal signs, massive bleeding with hemodynamic instability, clinical deterioration with shock, or toxic megacolon failing to improve after 24-48 hours of medical treatment 1
Hartmann's procedure (sigmoid resection with end colostomy) is the standard approach for patients with hemodynamic instability, significant comorbidities, or feculent peritonitis, with mortality rates of 12-20% 2
Primary resection with anastomosis may be considered only in carefully selected stable patients with purulent (not feculent) peritonitis, showing 40% lower mortality compared to Hartmann's procedure in observational studies 2
Medical Management for Non-Emergency Presentations
For Ulcerative Colitis Involving the Sigmoid:
Treatment intensity is determined by disease extent and severity, not just sigmoid involvement:
Flexible sigmoidoscopy should confirm diagnosis and severity within 48 hours, using phosphate enema preparation which is considered safe, though full colonoscopy is contraindicated in acute severe colitis 1
For mild-to-moderate disease: Oral mesalamine 2.4-4.8 g daily has demonstrated 29-41% remission rates at 8 weeks versus 13-22% with placebo 4
For moderate-to-severe disease refractory to 5-aminosalicylates: Infliximab 5 mg/kg at weeks 0,2, and 6, then every 8 weeks is indicated for inducing and maintaining remission 5
Corticosteroids for acute flares, but side effects limit usefulness for chronic therapy 6, 7
For Infectious Sigmoid Colitis:
Most bacterial colitis (Campylobacter, Salmonella, Shigella, E. coli, Yersinia) is self-limiting, but antibiotics should be used for high-risk patients and those with complicated disease 8
Stool culture and identification of specific bacterial toxins are required for definitive diagnosis before initiating targeted antibiotic therapy 8
For Ischemic Sigmoid Colitis:
Conservative management with bowel rest, fluid resuscitation, and broad-spectrum antibiotics is the mainstay for non-fulminant cases 3
Lower GI endoscopy within 48 hours to reach the distal-most extent provides endoscopic and histological confirmation and helps identify severe disease features predicting need for surgery 3
Critical Diagnostic Pitfall
Sigmoidoscopy alone is insufficient for evaluating inflammatory status in ulcerative colitis patients. In a study of 545 colonoscopic examinations, 40% of patients with no inflammation in the rectum and sigmoid colon had inflamed mucosa in the descending colon or more proximal portions 9. This is particularly critical for first-attack patients, where 14% had maximum inflammation beyond the splenic flexure 9.
Maintenance Therapy After Remission Induction
Mesalamine 2.4 g once daily maintains endoscopic remission in 84% of patients at 6 months 4
Endoscopic remission (not just clinical remission) is the therapeutic target, as mucosal healing after 1 year predicts only 1.6% colectomy risk versus 7% without healing 1
Reassessment with flexible sigmoidoscopy is appropriate at relapse, for steroid-dependent or refractory disease, or when considering colectomy 1