S4943 Acute Fibrostenotic and Fistulizing Ileal Crohn’s Disease: Timing of Biologic Therapy in the Setting of Obstruction and Infection

Introduction: Crohn’s disease (CD) is a chronic relapsing inflammatory disorder with highly variable phenotypes. Patients with stricturing and/or fistulizing disease are at increased risk for surgery and long-term disability. Biologic therapies, especially anti-tumor necrosis factor agents, are effective in altering disease progression when initiated early. However, acute complications such as obstruction or suspected infection may delay therapy, complicating management. Case Description/Methods: A 30-year-old biologic-naïve woman with stricturing ileal CD diagnosed in 2020 (baseline fecal calprotectin 5,000 μg/g) presented with worsening abdominal pain while on prednisone 40 mg daily pending biologic approval. Labs showed leukocytosis (white blood cell 20,000/μL) and C-reactive protein 30.2 mg/L. Computed tomography abdomen/pelvis revealed small bowel obstruction at the terminal ileum with circumferential thickening and an adjacent enhancing collection with punctate air, suggestive of early fistula formation. A second fluid collection between the bladder and uterus was suspicious for phlegmon or early abscess. Surgical evaluation recommended conservative management. A nasogastric tube was placed, and intravenous antibiotics and methylprednisolone were initiated. The patient clinically improved and was transitioned to oral prednisone and a regular diet. C-reactive protein improved to 14.6 mg/L; fecal calprotectin decreased to 222 μg/g. Colonoscopy was deferred due to obstruction. Small bowel follow-through was unremarkable. Thiopurine methyltransferase testing confirmed normal metabolism. Vedolizumab was denied by insurance. Given suspicion for evolving fistulizing disease, infliximab with azathioprine was selected. Biologic initiation was deferred for 2 weeks to allow infection control. Discussion: This case highlights the complexity of initiating biologic therapy in CD complicated by obstruction and possible infection. Imaging played a crucial role when endoscopy was contraindicated. Early identification of fistulizing disease is critical, and anti-tumor necrosis factor combination therapy remains the standard in this setting. Multidisciplinary coordination with surgery, infectious disease, and pharmacy facilitated safe initiation of appropriate long-term treatment. Timely recognition and treatment of early fistulizing CD are essential. When infection or obstruction precludes immediate therapy, a cautious, coordinated approach allows for stabilization and optimized treatment outcomes.