Intestinal Behçet Disease

Intestinal Behçet disease is gastrointestinal involvement in Behçet disease, a variable vessel vasculitis. It produces ulcers, typically in the terminal ileum and caecum, and can cause bleeding and perforation.

Gastrointestinal involvement is found in 3% to 25% of patients with Behçet disease, with a higher frequency in East Asia (Japan, Korea, Turkey) than in the Middle East. Onset is usually in the third to fourth decade, and recurrence after surgery is high (up to 50% or more).

Pathophysiology.

Immune activation in a genetically predisposed person (HLA-B51) leads to neutrophil driven vasculitis, ulceration and in severe cases necrosis and perforation.

Recurrent oral ulcers (nearly all patients), genital ulcers, uveitis, skin lesions and arthritis, with abdominal pain, diarrhoea, haematochezia, fever, weight loss and a right iliac fossa mass. Acute presentations include perforation and massive bleeding.

Red flags.

• Peritonitis from perforation.
• Massive rectal bleeding.
• Fistula or abscess.
• Neurological or vascular involvement.

The International Criteria for Behçet Disease are used for the systemic diagnosis (oral ulcers 2 points, genital ulcers 2, eye lesions 2, skin lesions 1, vascular lesions 1, neurological 1, pathergy 1; a score of 4 or more). Colonoscopy shows round or oval deep ulcers (usually 1 to 3 in the ileocaecal region). CT enterography shows wall thickening and complications. Biopsy excludes Crohn disease, tuberculosis and cytomegalovirus. C-reactive protein is raised. Test for tuberculosis and Clostridioides difficile.

Differential diagnosis.

• Crohn disease.
• Intestinal tuberculosis.
• Cytomegalovirus ulceration.
• Ischaemic colitis.
• Non-steroidal drug enteropathy.
• Yersiniosis.

Mild disease is treated with mesalazine and, when needed, corticosteroids. Moderate to severe or refractory disease needs immunosuppression. Operate for perforation, massive bleeding, fistula or obstruction, and prevent recurrence with immunosuppression after surgery.

• Prednisolone: 0.5 to 1 mg/kg orally once daily (maximum 60 mg daily) for 2 to 4 weeks, then taper over 8 weeks; for severe disease give methylprednisolone 1 mg/kg IV daily (maximum 80 mg) for 3 to 5 days; monitor glucose, blood pressure, bone health and infection; reduce in older adults and give bone and gastric protection.
• Azathioprine: 2 to 2.5 mg/kg orally once daily long term; maximum 3 mg/kg daily; check thiopurine methyltransferase activity first, and monitor blood counts and liver tests every 2 weeks for 2 months, then every 3 months; halve the dose in renal impairment and avoid with allopurinol or reduce the dose by 75%.
• Infliximab (refractory or severe): 5 mg/kg IV at weeks 0, 2 and 6, then every 8 weeks; maximum 10 mg/kg for each dose; monitor for infection, infusion reactions and screen for tuberculosis and hepatitis B first; avoid in heart failure.
• Adalimumab (alternative): 160 mg subcutaneously at week 0, 80 mg at week 2, then 40 mg every 2 weeks; maximum 80 mg every 2 weeks if the response is lost; same screening and monitoring.
• Colchicine (oral ulcers and arthritis): 0.5 mg orally two to three times daily; maximum 1.5 mg daily; monitor blood counts and diarrhoea; halve the dose in renal impairment.

Monitoring. Symptoms, C-reactive protein and blood counts every 3 months; colonoscopy at 6 to 12 months to check mucosal healing.

Referral and escalation. Gastroenterology, rheumatology and colorectal surgery.