S5025 Rapid Evolution to Penetrating Crohn’s Disease Shortly After Vedolizumab Induction in a Newly Diagnosed Crohn’s Patient

Introduction: Vedolizumab is a gut‐selective anti‐integrin approved for induction and maintenance of moderate‐to‐severe Crohn’s disease (CD). Its delayed onset (6–10 weeks) renders it less suitable for penetrating or fistulizing disease. We describe a young man whose disease rapidly evolved to intra‐abdominal abscess and entero‐enteric fistulas shortly after vedolizumab initiation, highlighting the need for guideline-based therapy selection and bridging strategies. Case Description/Methods: A 23-year-old man with CD diagnosed 3 months earlier (after partial small-bowel obstruction) began vedolizumab and prednisone 40 mg daily. Two weeks later, he developed right lower quadrant abdominal pain and non-bloody diarrhea, without fever for 3 days. White blood cell count was 23.9 × 10³/µL and c-reactive protein was 13.6 mg/dL. Computed tomography abdomen demonstrated severe terminal ileal inflammation and 2 rim-enhancing air–fluid collections adjacent to the distal ileum and sigmoid colon; magnetic resonance imaging enterography excluded fistulas. Empiric antibiotics with cefepime, vancomycin, and metronidazole were initiated. Prednisone and the second dose of vedolizumab were deferred due to concern of infection. A percutaneous Jackson-Pratt drain was placed and yielded 20 mL of purulent fluid growing aerobic gram-negative rods. Clinical and biochemical parameters improved rapidly. Antibiotics were de-escalated to ceftriaxone and metronidazole, then transitioned to oral ciprofloxacin/metronidazole to complete a 10-day course. The patient was discharged on day 5 and received vedolizumab the next day. One week later, computed tomography confirmed abscess resolution, but Fluoroscopy fistulogram revealed new small-bowel fistulas, necessitating prolonged drainage and multidisciplinary follow-up. Discussion: Vedolizumab’s slow onset requires steroid bridging, but steroids were halted once the abscess emerged to limit infection. In penetrating or fistulizing Crohn’s disease, anti-TNF therapy—particularly infliximab—offers superior efficacy and better prevention of complications; early use may have averted abscess formation in our patient. Timely recognition of vedolizumab’s pharmacodynamics and adherence to guideline-based risk stratification are essential to avoid adverse outcomes in newly diagnosed CD and rapid escalation of symptoms—even without fever—should prompt cross-sectional imaging to detect occult penetrating complications before sepsis ensues.