Current Consensus on Tuberculosis in Patients with Rheumatoid Arthritis

Tuberculosis (also known as TB) is a bacterial infection affecting the lungs and other parts of the body. It was almost completely gone from the United States but is now on the rise again. And patients being treated for rheumatoid arthritis may be at increased risk.

Before the development of anti-TB drugs in the late 1940s, TB was the leading cause of death in the United States. Drug therapy, along with improvements in public health and general living standards, resulted in a marked decline in the number of new cases of tuberculosis.

There are several reasons for the increased number of people developing this disease. Immigrants coming to the U.S. from developing Third World nations, rising homeless populations, and the emergence of HIV have led to an increase in reported cases. The new trend was first noticed in the mid-1980s, after a 40-year period of decline.

How does having rheumatoid arthritis (RA) figure in here? This particular group of patients when treated with some of the newer immune modifying drugs are experiencing a reactivation of latent (inactive or silent) tuberculosis. The same thing is happening to organ transplant recipients and patients with other immune-based problems who are being treated with these kinds of medications.

What does this mean for people with rheumatoid arthritis (RA)? Should they stop taking the helpful medications for the sake of avoiding tuberculosis? Should they be tested more often for TB?

A group of experts got together to discuss these diagnostic issues. They offered a series of what they refer to as clinical pearls to help guide patients and physicians in this matter. Here's a quick summary of the most important points:

People with latent tuberculosis aren't contagious and can't spread TB. They don't have any symptoms of TB but they need to be treated to prevent TB from becoming active.
Anyone with rheumatoid arthritis should be screened for TB regularly -- even if they are not being treated with the newer disease-modifying anti-rheumatic medications (DMARDs). That's because for some (as yet unknown) reason, people with rheumatoid arthritis (RA) get TB four times more often than folks who don't have RA.

Patients with RA should be tested for tuberculosis before being put on the disease modifying antirheumatic medications.

How serious is this risk of tuberculosis for rheumatoid arthritis (RA) patients? We mentioned the four-fold increase in cases of tuberculosis (TB) among people with rheumatoid arthritis but there's more. The latent form of TB can become active. This happens about 10 per cent of the time. And a reactivated case of TB can be fatal.

What does it mean "anyone with rheumatoid arthritis should be screened for TB regularly"? The experts recommend yearly tests for TB. That means an updated medical history, tuberculin skin test, chest X-ray, and physical examination.

Each physician will decide exactly which tests are needed for individual patients. There are a couple of additional tests that may be required (e.g., sputum analysis, Interferon-Gamma Release Assay or IGRA).

The standard skin test for tuberculosis (TB) isn't fool-proof. It is possible to get a false-negative response. In other words, the test says the patient does NOT have TB when in fact the patient DOES have it. Sometimes the skin test is given a second time one-to-four weeks after the first test. Again, the physician will make this decision based on each patient's ability to react to the tuberculin test.

Diagnosis usually means there's some kind of treatment involved. The authors of these clinical pearls mention treatment briefly but promise a second article soon just on treatment.

For now, they point out that treating latent tuberculosis can reduce the risk of active infection by 60 per cent. That statistic supports the recommendation to screen regularly and treat rheumatoid arthritis patients who test positive for latent tubercular disease.

Reference: Bella Mehta, MBBS, and Petros Efthimiou, MD. Latent Tuberculosis Infection in RA: The Disease and the Diagnosis. In The Journal of Musculoskeletal Medicine. June 27, 2011. Vol. 28. No. 7.

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