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 presenting with perianal fistula, discharge, induration, and low-grade fever for 3 weeks would be option D: MRI. This approach is supported by the need for a detailed anatomical evaluation to identify any hidden abscesses and determine the appropriate treatment strategy, as suggested by the symptoms of possible perianal sepsis or abscess formation 1. After obtaining the MRI, treatment would likely involve a combination approach including:

• Possible surgical drainage if an abscess is present
• Antibiotics (typically ciprofloxacin or metronidazole) to control infection, although their effectiveness in treating Crohn’s perianal fistulas is based on uncontrolled case series and not controlled trials 1
• Optimization of the biological therapy, considering that higher infliximab doses may be beneficial for perianal fistulising disease, with target levels >10 μg/mL associated with better response 1 Simply increasing the infliximab dose without proper assessment could be dangerous if an undrained abscess is present. While antibiotics may ultimately be part of treatment, they shouldn't be initiated without understanding the full extent of the disease. Similarly, a swab from discharge provides limited information compared to the comprehensive anatomical details an MRI would provide for this complex perianal Crohn's manifestation. The use of drug levels to guide dosing, as discussed in the TAXIT study, may also be beneficial in optimizing treatment, especially for patients with perianal fistulae who may require higher levels of infliximab 1.

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.