Magnetic resonance image healing correlating with long‐term clinical improvement in proximal small bowel Crohn disease treated with first‐line vedolizumab therapy

A 23-year-old male nurse of South American origin was undergoing investigation of abdominal pain. He had a normal gastroscopy and colonoscopy; however, his C-reactive protein (CRP) level was raised at 25 mg/L. Video capsule endoscopy was performed but complicated by retention. He subsequently presented to the hospital with peritonism, and computed tomography of his abdomen showed thickened, dilated proximal small bowel and retained video capsule at a jejunal stricture (Fig. 1A) with local perforation-fistula from jejunum to colon. Surgical resection of 43 cm of jejunum and 9 cm of transverse colon confirmed stricturing and penetrating small bowel Crohn disease. He was commenced on metronidazole 400 mg three times a day and azathioprine 150 mg daily following surgery given concerns for recurrence. Six months following the patient’s operation, he had a clinical recurrence of small bowel Crohn disease, with a raised calprotectin level of 554 mg/kg and was commenced on controlled ileal-release budesonide 9 mg daily for 6 weeks to reinduce remission. Because of his concerns regarding the risk of his occupational exposure to infections as well as his desire to visit family members in a developing country overseas, he refused to commence an antitumor necrosis factor agent. Instead, intravenous vedolizumab induction therapy followed by 8-weekly maintenance was commenced, in addition to his regular azathioprine. After 1 year of treatment, the patient was in clinical and biochemical remission with a CRP level of 4.4 mg/ L. However, serial magnetic resonance enterography (MRE) performed yearly for the next 3 years showed ongoing active inflammation in the jejunum (Fig. 1B, C), not significantly improved compared with prior imaging, despite his clinical and biochemical remission (calprotectin 26.4 mg/kg). Given the only partial response, his vedolizumab was escalated to 4-weekly dosing and his subsequent MRE 1 year later showed significant improvement in the disease activity with near complete radiological remission. He was then deescalated to 8-weekly dosing and remains in remission with transmural healing (Fig. 1D) whilst being monitored with yearly calprotectin testing, MRE and intestinal ultrasound (IUS). Stricturing proximal small bowel Crohn disease is a high-risk condition and is not always amenable to endoscopic assessment of healing, which is currently the therapeutic target and may not correlate with clinical and biochemical markers. As such, surrogate follow-up tools including MRE and IUS assessing transmural healing are essential to monitor disease activity for signs of progression and may in fact lead to better outcomes, as in our case. This case also supports the use of vedolizumab as both a first-line agent in small bowel Crohn disease, as well as its efficacy in both dose escalation and deescalation in achieving transmural healing, which was not known at the time but there is now growing evidence that imaging supports its efficacy in dose escalation. This case also demonstrates that transmural healing may take over 1 year to occur, and so symptomatic control is insufficient in high-risk cases such as this.