About TB..

suzanne4, RN · Mar 15, 2004

Just because you are exposed to TB does not mean that you are going to get it.

WalkingInTheRain · Mar 15, 2004

But, people I know tested positive for it and they had to take Meds for it. Because, someone told me they make you take the Meds where it won't develop into it..

elkpark · Mar 15, 2004

My Mantoux test converted while I was in nursing school (long, long ago, in a galaxy far, far away ... :chuckle ). I had to turn myself in to the local Public Health department, and take INH for a year. So, I'm v. familiar with how all this works.

Most people who are exposed to TB never come close to developing the active disease (some public health people say that everyone who lives in a city in the US has been exposed ...) The medications carry a fair amount of risk of liver damage -- in the US, prophylactic treatment (what I had to take) is not done if you're over 35, because that is the point at which the risk of liver damage outweighs the risk of developing the disease, and they don't do prophylactic treatment in Europe at all, because they consider the risk of liver damage to be too great to justify the treatment, period (at least, that was how it worked 'way back when, when I was doing this. Things may have changed since then.)

The point of the prophylactic treatment is to kill off all the little beasties that are lurking in your system, waiting for the day when you may be too run down, too weak, too poorly nourished, or your immune system may be compromised by some other agent/situation. UNFAIR AS IT SEEMS, the year of prophylaxis does not give you any immunity to the disease. Once you're done with the prophylactic treatment, your risk of exposure is just the same as anyone else's. On the bright side :chuckle , you never have to have a Mantoux test again ... Once you've converted to a positive Mantoux, you're positive forever, so they're meaningless from then on (and, in fact, somewhat dangerous -- you can have so strong a positive reaction to the test that the site necroses and you slough tissue. Yuk!)

Hope this info is helpful (and not too terribly out of date and incorrect ... :) )

WalkingInTheRain · Mar 15, 2004

Thanks for the responses

AUN · Mar 15, 2004

HI,

TB can be recurrented that why they have to take medication for 6 months or some cases up to 1 year and after that they need to be following for CXR .

That what I remember from the book.

MRhodes · Mar 25, 2004

Here is an article I wrote on TB screening. Hope it may be of some use to someone. It didn't cut and paste to well (the charts), but if anyone wants it, PM me and I'll send it to you.

TB Skin Testing

Melba Rhodes, RN, BSN, CIC

Objectives: Discuss the administration, reading and interpretation of the TB skin test. Discuss reasons for false positives and false negatives.

The TB Skin TestThe tuberculin skin test is used to determine whether a person has TB infection or latent TB (non-infectious). A substance called tuberculin is injected in between the layer of the skin (intradermally). Tuberculin is protein derived from tubercle bacilli that have been killed by heating. In most people who have TB infection, the immune system will recognize the tuberculin because it is similar to the tubercle bacilli that caused the infection. This will cause a reaction to the tuberculin. Tuberculin is used for diagnosing TB infection; it is not a vaccine.A health care worker (usually a nurse) will inject a small amount of testing fluid (called tuberculin) just under the skin on the lower part of your arm. Do not scratch or rub the site. After 2 or 3 days, the health care worker will measure your reaction to the test. You may have a small bump where the tuberculin was injected. The health care worker will measure this bump and tell you if your reaction to the test is positive or negative. A positive reaction usually means that you have latent (inactive) TB infection.

A TB skin test is the only way to find out if you have latent (inactive) TB infection.

You should get tested for TB if you:

þ Have spent time with a person with known or suspected to have TB disease

þ Have HIV infection or another condition that puts you at high risk for TB disease

þ Think you might have TB disease

þ Are from a country where TB disease is very common (most countries in Latin America and the Caribbean, Africa, Asia, Eastern Europe, and Russia)

þ Inject drugs

þ Live or work somewhere in the U.S. where TB disease is more common (homeless shelters, migrant farm camps, prisons and jails, hospitals, and some nursing homes)

þ Are a Healthcare Worker

If you have a positive reaction to the skin test, you will need other tests to see if you have TB disease. These tests usually include a chest x-ray and a test of the material you cough up. A positive skin test does not mean that you cannot continue to work. As long as you have no symptoms of TB (cough, night sweats, fever, weight loss, etc.), you can continue to work.

If you have TB disease, you will need to take medicine to cure the disease. This medication is the same medication used to treat active TB. You will generally take the medication for 6 to 9 months.

If you have recently spent time with someone with infectious TB, your skin test reaction may not be positive yet. It takes about 8 weeks for the skin test to become positive after infection. You may need a second skin test 10 to 12 weeks after the last time you spent time with the infectious person. If your reaction to the second test is negative, you probably do not have latent (inactive) TB infection. You should report any symptoms of TB (i.e.; cough lasting longer than two weeks, fatigue, coughing up blood) to the Employee Health Office immediately.

How can you prevent exposure to tuberculosis?

1. Screen each patient upon admit for signs and symptoms of TB. Your policy may call for administering a TB skin test upon admit and annually.

2. Wear an N95 Respiration when treating a patient with suspected or known TB. The patient should be isolated in a negative pressure room. If your facility does not have a negative pressure isolation room, have the patient wear a surgical mask (if coughing) while TB is being ruled out or the patient is being transferred.

Post test instructionsAs the tuberculin solution is injected, a 6 to 10 mm wheal will raise up at the site. This is quickly absorbed and no dressing is required.Do not massage the site. Doing so may cause the medication to disperse into the tissue or leak out of the site.Apply slight direct pressure if the site bleeds.Do not rub area when bathing or use perfume or lotion on the site.Do not put an adhesive bandage over the site.Return to have test read when instructed, no longer than 72 hours. If test is not read then, it will need to be repeated.Notify the employee Health Nurse of any itching or redness at the site within the first 15 minutes of application.Reports of delayed reaction have occurred. Report any hardened area that occurs for up to 14 days after application. This may indicate early TB infection and the test should be repeated in a month.

TB Skin TestingTB skin testing is a test of the body’s reaction to purified protein derivative (PPD) of tuberculin via delayed type hypersensitivity (similar to the body’s reaction to poison ivy). This delayed reaction typically appears 48 to 72 hours after placement of the TB skin test.

False Positive False Negative

Atypical mycobacterium infection (MAC, m. bovine, etc.) Recent vaccination (Rubella, measles, influenza)

Infant under 6 months (due to immature immune system)

Early in TB infection or disease (it takes about 2 months for hypersensitivity reaction to the TB skin test to develop)

Immunosupression (Hodgkin’s, AIDS, Large dose corticosteroids)

Pen Method of Measuring TB Skin Tests

The reaction is an area of induration (swelling that can be felt) around the site of the injection. The diameter of the indurated area is measured across the forearm.

1. Place a pen about 2 inches away from the suspected induration (ignore the redness).

2. Glide the pen until you meet resistance.

3. Do the same from the other direction.

4. Measure the distance between the 2 lines.

Classifying the ReactionWhether a reaction to the Mantoux tuberculin skin test is classified as reactive depends on the size of the induration and the person's risk factors for TB. 5 or more millimeters is considered a positive reaction for the following people: - People with HIV infection - Close contacts of people with infectious TB - People with chest x-ray findings suggestive of previous TB disease - People who inject illicit drugs and whose HIV status is unknown 10 or more millimeters is considered a positive reaction for the following people: - People born in areas of the world where TB is common (foreign-born persons) - People who inject illicit drugs but who are known to be HIV negative - Low-income groups with poor access to health care - People who live in residential facilities (for example, nursing homes or correctional facilities) - People with medical conditions that appear to increase the risk for TB (not including HIV infection), such as diabetes - Children younger than 4 years old - People in other groups likely to be exposed to TB, as identified by local public health officials 15 or more millimeters is considered a positive reaction for people with no risk factors for TB. In most cases, people who have a very small reaction or no reaction probably do not have TB infection.

What about BCG Vaccination?

There is NO RELIABLE WAY to distinguish a positive tuberculin reaction caused by vaccination with BCG from a reaction caused by true TB infection. However, the reaction is more likely to be due to TB infection if any of the following are true:

- The reaction is large

- The person was vaccinated a long time ago

- The person comes from an area of the world where TB is common

- The person has been exposed to someone with infectious TB disease

- The person's family has a history of TB disease

TRUE or FALSE

1. It takes about 25 weeks for the skin test to become positive after infection.

2. Symptoms of TB include cough and night sweats.

3. A positive TB skin test means you cannot work in a healthcare facility.

4. If you have TB disease, you will need to take medicine to cure the disease.

5. Reports of delayed reaction, up to 14 days after application, have occurred.

6. A TB skin test is the only way to find out if you have latent TB infection.

7. If you have a positive reaction to the skin test, you will need other tests to see if you have TB disease.

8. A false positive may be caused by recent vaccination.

9. Wear an N95 Respiration when treating a patient with suspected or known TB.

10. If test is not read within 72 hours it will need to be repeated.

Answers

1. False

2. True

3. True

4. True

5. True

6. True

7. True

8. False

9. True

10. True