What is the best management for a patient with Crohn's disease, treated with infliximab (infliximab), presenting with a perianal fistula, discharge, induration, and low-grade fever for 3 weeks?

From the Guidelines

The best management for a case of Crohn's disease on infliximab who presents with perianal fistula, discharge, induration, and low-grade fever for 3 weeks is option D: MRI. An MRI should be performed first to properly evaluate the extent and complexity of the perianal fistula, identify any hidden abscesses, and guide further management decisions. The patient's symptoms of discharge, induration, and fever suggest possible abscess formation or fistula complications that require detailed anatomical assessment before treatment modifications. While antibiotics (such as ciprofloxacin or metronidazole) are often part of perianal Crohn's disease management, they should be initiated after proper imaging assessment, as suggested by the american gastroenterological association medical position statement: perianal crohn's disease 1. Simply increasing the infliximab dose without ruling out an abscess could worsen the infection. A swab culture from the discharge may be helpful but is insufficient for comprehensive evaluation. The MRI findings will determine whether surgical drainage is needed before adjusting medical therapy, making it the critical first step in managing this complex presentation of perianal Crohn's disease, as supported by the british society of gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults 1. Higher infliximab doses may be beneficial for perianal fistulising disease, with target levels >10 μg/mL associated with better response, as noted in the british society of gastroenterology consensus guidelines on the management of inflammatory bowel disease in adults 1. However, the initial step should focus on assessing the fistula and potential complications through imaging rather than immediately adjusting the medication dose. Optimal management of perianal fistulising Crohn's disease requires a multidisciplinary approach, including diagnostic accuracy achieved by a combination of modalities, and surgical drainage of sepsis as the first line therapy before initiating immunosuppressive treatment, as stated in the global consensus on the classification, diagnosis and multidisciplinary treatment of perianal fistulising crohn's disease 1. Therefore, an MRI is essential for guiding the management of this patient, considering the potential for abscesses or other complications that need to be addressed before modifying the treatment plan.

From the FDA Drug Label

In the second trial (ACCENT II [Study Crohn's II]), patients who were enrolled had to have at least 1 draining enterocutaneous (perianal, abdominal) fistula. At Week 14,65% (177/273) of patients were in fistula response Patients randomized to infliximab maintenance had a longer time to loss of fistula response compared to the placebo maintenance group Patients who achieved a fistula response and subsequently lost response were eligible to receive infliximab maintenance therapy at a dose that was 5 mg/kg higher than the dose to which they were randomized

The best management for a patient with Crohn's disease on infliximab who presents with perianal fistula and discharge, induration, and low-grade fever for 3 weeks is to continue or adjust infliximab therapy.

• The patient is already on infliximab, and the drug label suggests that patients who achieve a fistula response and subsequently lose response can be eligible to receive infliximab maintenance therapy at a dose that is 5 mg/kg higher than the dose to which they were randomized 2.
• There is no direct information in the label to support the use of antibiotics, swab from discharge, or MRI as the best management for this specific scenario.

From the Research

Best Management for Perianal Fistula and Discharge in Crohn's Disease

The best management for perianal fistula and discharge in Crohn's disease involves a combination of medical and surgical approaches.

• The use of infliximab, a chimeric monoclonal antibody targeting human tumor necrosis factor alpha (TNF), is approved for the treatment of fistulizing Crohn's disease 3, 4.
• An exam under anesthesia (EUA) by a surgeon allows for complete inspection of the fistula, incision and drainage of an abscess, and placement of a seton, which can improve the initial response and reduce the recurrence rate of perianal fistulas 3.
• Concomitant immunosuppressive therapy with azathioprine, 6-mercaptopurine, or methotrexate may result in improved outcomes due to a reduction in the frequency of human anti-chimeric antibody formation, acute infusion reactions, and a reduced risk of delayed hypersensitivity-like reactions and formation of antinuclear antibodies 4.
• Local injection of infliximab along the fistula tract may be an effective and safe treatment for perianal fistulas in Crohn's disease, with a response rate of 72.7% and a remission rate of 36.4% 5.
• Magnetic resonance imaging (MRI) can be used to assess the behavior of perianal fistulas before and after infliximab treatment, and to evaluate the inflammatory changes in the fistula tracks 6.

Diagnostic Approaches

• MRI can be used to evaluate the extent of perianal fistulas and to assess the response to treatment 7, 6.
• A swab from the discharge can be used to identify any infectious causes of the fistula and to guide antibiotic therapy.
• EUA and seton placement can be used to drain abscesses and to reduce the risk of recurrence.

Treatment Options

• Increasing the dose of infliximab may be considered in patients who do not respond to the initial dose, but this should be done with caution and under close monitoring 4.
• Antibiotics may be used to treat any infectious causes of the fistula, but they are not a substitute for definitive treatment of the fistula itself.
• MRI can be used to guide the treatment of perianal fistulas and to evaluate the response to treatment.