QD 80 - Latent TB Save

Welcome to QD Clinic. I'm Jack Cush from RheumNow. QD Clinic is brought to you by RheumNow live. Our patient today, missus DC, is a 42 year old who comes in with a newly diagnosed rheumatoid arthritis. She has a fatty liver, she has diabetes, she's not responding nonsteroidals and low dose prednisone, she gets put on methotrexate, and after twelve weeks, she has an AST of 47 and ALT of 51.

Everyone's a little bit nervous about what to do, and how we can best manage this. The decision is made to put her on a TNF inhibitor and lower her methotrexate. She gets tested with a QuantiFERON test and it comes back positive. She is from The United States, her family is from Central America, and she has no known contacts, with people who have TB. She has no signs or symptoms, her chest exam is normal, her chest x-ray was done, and that's normal.

She meets the definition of having latent tuberculosis. So the question is, what do you do? You want to put her on a TNF inhibitor? How do you best manage that? Again, latent tuberculosis is a positive test for TB reactivity.

That could be a tuberculin skin test, PPD test, or it could be a T spot, or it could be a QuantiFERON spot. Any of these, especially in a high risk individual, someone born in endemic country, any of those are positive is reason enough for treatment if they in fact meet the definition of latent disease. You can assume it's latent disease because again they have no signs and symptoms, a negative chest x-ray, and they have a positive test. Now, you could go one step further in some individuals and culture everything, culture urine, sputum, etc, because there's a few people, especially high risk individuals born in endemic areas, who still could be positive. And that would change the treatment because that would be active TB if they had a positive culture.

So, in this patient who needs to be on treatment, what are you going to do? Well, first you should know how frequent this occurs. If you're running a clinic here in The United States or another non endemic country where the TB rate is roughly less than five per one hundred thousand individuals, the risk of finding a positive PPD or QuantiFERON or IGRA test, it's about five to ten percent. It may be five percent, and then if you do it the first time and then repeat it three, six months later or when they switch their first TNF, and then you'll find another few percent who will be positive. Those people will have been anergic or may have had an indeterminate result, and then with control of inflammation, they'll get their full immune reactivity back and show you they actually are a latent TB person with reactivity.

I do recommend second time testing. I do not recommend annual testing. That is a special kind of stupid. There's no good reason for it. You should repeat test when risk changes with exposure, for instance.

But if you're a skippy living in Connecticut with no change in risk to repeat the testing is just not of any value even though it's requested by insurance companies. I do recommend second testing because as I said, there's a few percentage of people who really are latent TBs who would be missed on initial testing. And then when do you what do you do? You get a positive result, you put them on treatment. What treatment do you put them on?

You have several options. There are some newfangled options that you have to come to RheumNow live to learn about. Kevin Winthrop from Oregon Health Science Center is the infectious disease of the rheumatology stars. He knows our patients, our business. He'll talk on how to TB manage and test, but he would tell us of some newer regimens.

The old regimen is six months of INH grade B evidence, nine months of INH grade A evidence, grade b evidence for rifampin for for four months. I I like rifampin for four months. And with both INH and rifampin, you have to do some heavy TB, LFT testing baseline and every month for two months, and then maybe if there's no elevations, can do it every other month until they're stopped because LFT elevations on those drugs can be disastrous. The question is, you start someone on treatment for LTBI, when can you start treatment with the TNF inhibitor? The FDA rules on this are in the package insert, and they all say the same thing.

Treatment with prophylaxis should begin before treatment with the TNF inhibitor, before. It doesn't say a week before, six months before, nine months before, these are all idiotic recommendations from colleagues, ID specialists, pulmonary specialists. The FDA, in consultation with the largest division of the CDC, said before, meaning, I can throw three hundred milligrams of INH down the throat of one of my patients who has latent TB and then stick an IV in their arm and give them Remicade, and that is okay. I've done that many times. No one's going to reactivate and flare.

In fact, they'll just get better with regard to the arthritis, which you thought was so severe they needed a TNF inhibitor. So before means before, not one week, two weeks, six weeks, six months, nine months. Again, those are all idiotic recommendations. Latent TB is actually really easy to monitor. Patients need to know how long they're gonna be on that therapy and how and you set the expectations for them.

And again, frequent and aggressive monitoring of LFTs are in order. Come to RheumNow. You can hear Kevin Winthrop lecture on this. Let me tell you some of the comments that we got from RheumNow live last year. One of the best first days of a conference I've ever been to, a new level of engagement with the speakers at RNL two thousand nineteen.

Doctor Seal left us with good clinical thoughts and ideas. It was two and a half fun days of intense learning at RheumNow live. Excellent talks and long q and a's. Mike says very slick meeting format. And Thomas says, great job.

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