NIV Congres

Introduction: The introduction of tumor necrosis factor-alpha (TNF-α) inhibitors has changed management of patients with inflammatory bowel disease (IBD). However, multiple adverse events have been described. Incident cases of tuberculosis in patients treated with TNF-antagonists after a negative screening have been reported, suggesting that improved pretreatment tuberculosis testing is mandatory. Standard latent TB infection (LTBI) screening includes a chest radiograph, a tuberculine skin test (TST) and/or an interferon-gamma release test (IGRA).We describe a case of active TBC in a male treated with infliximab with negative pretreatment tests for Crohn’s disease.

Case report: A 54-year old male, emigrated from Sri Lanka in 1995, was diagnosed with Crohn’s disease in 2005. He remained in clinical remission on azathioprin therapy till February 2012. Than he presented with an erythema nodosum. Colonoscopy revealed a severe colitis. A TST was performed to exclude tuberculosis; but showed a indeterminate TST result (11 mm) with previous BCG-vaccination. In order of LTBI, an additive Quantiferon-TB test was negative. A specialized TBC-pulmonologist considered the patient not at risk. Three infusions of infliximab were given. The clinical course was complicated by the development of peri-anal abscesses which cost him two hospitalizations. He developed periodic fever, 40 ºC despite antibiotics and adequate surgical treatment. CT scan and colonoscopy were normal besides improved perianal disease. A second Quantiferon-TB test and blood cultures were negative. A PET-CT showed ascites, several mediastinal PET-positive lymphomas and small nodules in the lungs suspicious for lymphoma. Mediastinal lymph node biopsies were taken. Ziehl-Neelsen testing (on biopsies and ascites) was negative. The ascites mycobacterial tuberculosis and species PCR were negative. The first PCR results on the lymph node biopsy were negative. After 5 days, pathological results on the lymph nodes showed necrotizing inflammatory granuloma matching a TBC infection. Patient started therapy with rifampicin, isoniazid, ethambutol, and pyrazinamid. Infliximab was discontinued. Subsequently adenosine deaminase testing of ascites was positive for tuberculous peritonitis. Only one PCR became positive on the lymph nodes and five weeks after the lymph node biopsies determination showed Mycobacterium tuberculosis.

Conclusion: This case illustrates that, despite extensive negative TBC infection screening there is still a risk of the development of overt TBC after starting anti-TNF therapy. We therefore propose that all patients having any additional risk factors for reactivation of TBC should be treated with isoniazid preventive therapy before starting TNF-α inhibitors. Better LTBI should be developed in the nearby future.