More information about text formats
The introduction of newer TNF blockers (etanercept, infliximab, adalimumab) has greatly improved the treatment of chronic inflammatory disorders such as Crohn’s disease, rheumatoid arthritis and ankylosing spondylitis. As the main side effect however many patients are rendered susceptible to infections.(1) Especially the activation of latent tuberculosis infection (LTBI) is a common and dangerous problem....
The introduction of newer TNF blockers (etanercept, infliximab, adalimumab) has greatly improved the treatment of chronic inflammatory disorders such as Crohn’s disease, rheumatoid arthritis and ankylosing spondylitis. As the main side effect however many patients are rendered susceptible to infections.(1) Especially the activation of latent tuberculosis infection (LTBI) is a common and dangerous problem. A national three and half year survey in France found 56 cases of activated LTBI due to infliximab.(2)
Physicians are therefore advised to screen for LTBI before commencing any TNF blocker. All recommendations include careful history, and chest radiograph.(1,3) The need for tuberculin skin testing has been questioned as a high incidence of anergy in Crohn’s patients on immunosuppressive therapy has been reported.(4) It now seems to be consensus not to skin test these patients and to give chemoprophylaxis for certain ethnic groups.(5) Careful monitoring for activation of LTBI is required for patients not receiving chemoprophylaxis.
We initiated Infliximab therapy in an anxious 28 year old female with refractory Crohn’s disease. Screening for LTBI showed a normal chest x-ray and tuberculin skin test, but at that stage the patient was receiving high dose steroids. Two months later she presented to her general practitioner with a productive cough. Sputum cultures were obtained and a preliminary report revealed mycobacteria growth. However as the patient did not develop any constitutional symptoms and final culture results showed an atypical mycobacterium it was opined that this rather represents a contaminant.
Not only false negative tuberculin skin tests but also false positive cultures for mycobacteria can cause a diagnostic dilemma in Crohn’s patients. Furthermore this can cause additional distress in already anxious patients.
1. Keane J. TNF-blocking agents and tuberculosis; new drugs illuminate an old problem. Rheumatology 2005 March 1
2. Baldin B, Dozol A, Spreux A, Chichmanian RM. Tuberculosis and infliximab treatment. National surveillance from January 1, 2000 through June 30, 2003. Presse Med 2005 Mar 12; 34 (5):353-7
3. Salmon D. Recommendations about the prevention and management of tuberculosis in patients taking infliximab. Joint Bone Spine 2002;69:170-2
4. British Thoracic Society with Ormerod LP, Milburn H, Gillespie S, Ledingham JM, Rampton DS. Recommendations for assessing risk, and managing tuberculosis infection and disease in patients due to start anti-TNF alpha treatment. Thorax, in press 2005. (Also online at http://thorax.bmjjournals.com/cgi/rapidpdf/thx.2005.046797v1)
5. Rampton DS. Preventing TB in patients with Crohn’s disease needing Infliximab or other anit-NTF therapy. Gut, 2005; 54: 1360 - 1362.