What is the appropriate management for a patient with ileitis and superimposed enteritis?

Management of Ileitis with Superimposed Enteritis

Start intravenous corticosteroids (hydrocortisone 400 mg/day or methylprednisolone 60 mg/day) immediately plus intravenous metronidazole without waiting for stool culture results, because distinguishing active inflammatory disease from infectious or septic complications is extremely difficult in this clinical scenario. 1, 2

Immediate Diagnostic Work-Up

• Obtain stool cultures for bacterial pathogens (especially Yersinia spp., the most common infectious cause of acute ileitis), Clostridioides difficile toxin, and parasites, but do not delay corticosteroid therapy while awaiting results. 2, 3
• Perform ileocolonoscopy with biopsies from at least five sites (including ileum and rectum, two specimens per site) to confirm diagnosis and differentiate ulcerative colitis with backwash ileitis from Crohn's disease. 2, 4
• Send tissue for CMV immunohistochemistry if the patient is critically ill or has been in the ICU, as CMV enterocolitis can coexist with or unmask underlying inflammatory bowel disease. 5
• Obtain contrast-enhanced CT abdomen/pelvis to evaluate for bowel wall thickening, pneumatosis, perforation, or abscess formation. 2

Severity Assessment and Monitoring

• Monitor vital signs four times daily, stool frequency with blood presence, and perform serial abdominal examinations every 4–6 hours for peritoneal signs (rebound tenderness, guarding, rigidity). 2
• Repeat laboratory panel (CBC, ESR/CRP, electrolytes, albumin, liver function tests) every 24–48 hours to track inflammatory activity. 2
• Obtain plain abdominal radiograph if colonic dilatation is suspected; transverse colon diameter > 5.5 cm indicates severe disease requiring urgent intervention. 2

Initial Medical Management

Severe Disease (Hospitalization Required)

• Administer intravenous hydrocortisone 400 mg/day or methylprednisolone 60 mg/day immediately. 1, 2, 4
• Add intravenous metronidazole concomitantly because active inflammatory disease cannot be reliably distinguished from septic complications in this presentation. 1, 2
• Provide supportive care: IV fluids, electrolyte replacement, blood transfusion to maintain hemoglobin > 10 g/dL, and subcutaneous heparin for venous thromboembolism prophylaxis. 2
• Offer enteral or parenteral nutritional support if the patient is malnourished. 2
• Continue intravenous steroids for 3–5 days with response assessment; do not extend beyond 7 days if the patient is not responding. 6

Moderate Disease (Oral Therapy Appropriate)

• Prescribe oral prednisolone 40 mg daily for moderate-to-severe ileocolonic disease or for mild disease that failed mesalazine. 1, 2, 4
• Taper prednisolone gradually over 8 weeks; rapid tapering (< 8 weeks) is associated with early relapse. 1, 2, 4
• For isolated ileo-cecal moderate disease, budesonide 9 mg daily is an alternative, though marginally less effective than prednisolone. 1, 4

Mild Disease

• High-dose mesalazine 4 g daily may be sufficient as initial therapy for mild ileocolonic disease. 1, 2, 4

Rescue Therapy for Steroid-Refractory Disease

• By day 3, > 8 stools/day or 3–8 stools/day with CRP > 45 mg/L predicts an ≈ 85% colectomy rate and signals the need for rescue therapy. 2
• Rescue options: infliximab 5 mg/kg IV at weeks 0,2,6 or cyclosporine 2 mg/kg/day IV. 2, 6
• Avoid infliximab in patients with obstructive symptoms or active sepsis (intra-abdominal abscess). 1, 4, 6
• Screen for tuberculosis before initiating anti-TNF therapy. 2

Adjunctive and Steroid-Sparing Agents

• Add azathioprine 1.5–2.5 mg/kg/day or mercaptopurine 0.75–1.5 mg/kg/day as adjunctive steroid-sparing agents in patients requiring more than one corticosteroid course per year. 1, 2, 4
• These thiopurine agents have a slow onset of action (8–12 weeks) and should not be used as sole therapy for active disease. 1, 2
• Elemental or polymeric diets are less effective than corticosteroids but may be used in patients with contraindications to steroids or those who prefer to avoid them. 1
• Metronidazole 10–20 mg/kg/day is effective but not recommended as first-line therapy due to side effects; reserve for colonic or treatment-resistant disease. 1, 4

Surgical Indications

• Urgent surgery is indicated for toxic megacolon not improving after 24–48 hours of medical therapy, colonic perforation, massive hemorrhage with hemodynamic instability, or failure of rescue therapy after 4–7 days. 2
• Presence of peritoneal signs (rebound tenderness, guarding, rigidity) mandates immediate surgical consultation. 2
• Surgery should be considered for patients who have failed medical therapy and may be appropriate as primary therapy in patients with limited ileal or ileo-cecal disease. 1, 4

Special Considerations and Differential Diagnosis

• Infectious ileitis (especially Yersinia spp.) is the most common cause of acute ileitis in immunocompetent patients, accounting for approximately 33% of cases. 3
• CMV enterocolitis should be suspected in critically ill or ICU patients with partial response to initial therapy; this may unmask underlying Crohn's disease. 5
• Backwash ileitis (continuous extension of inflammation from cecum into terminal ileum) occurs in up to 20% of patients with extensive ulcerative colitis and tends to follow a more refractory course. 4
• Additional small bowel imaging (MR enterography or CT enterography) should be performed to differentiate ulcerative colitis with backwash ileitis from Crohn's disease. 2, 4
• Consider alternative explanations for symptoms beyond active inflammatory disease: bacterial overgrowth, bile salt malabsorption, fibrotic strictures, dysmotility, or medication-induced ileitis (NSAIDs). 1, 4, 7
• Gynecologic conditions account for approximately 9% of cases initially diagnosed as acute ileitis, representing 14% of cases among female patients. 3

Critical Pitfalls to Avoid

• Do not postpone corticosteroid therapy while awaiting stool microbiology results in suspected severe inflammatory ileitis with enteritis. 2
• Do not taper prednisolone faster than 8 weeks, as rapid tapering precipitates early relapse. 1, 2, 4
• Do not use infliximab in patients with obstructive symptoms or active intra-abdominal sepsis. 1, 4, 6
• Do not continue intravenous corticosteroids beyond 7 days in patients who are not responding. 6
• Do not use thiopurine or methotrexate monotherapy for induction of remission in active disease. 6

Follow-Up and Maintenance

• If infectious causes are excluded and inflammatory bowel disease is confirmed, continue maintenance therapy with aminosalicylates (mesalazine ≥ 2 g daily), azathioprine, or mercaptopurine to reduce relapse risk. 2
• Faecal calprotectin can be used as a non-invasive marker to assess inflammation and monitor treatment response. 4
• Repeat endoscopy at 6 months to assess mucosal healing and confirm diagnosis if initial presentation was complicated by CMV or other superimposed infection. 5