Rx in PPD ve with h/o BCG in childhood, no symptoms, xray normal

[sshr23]

Do this patient who is 28y need Rx?

[National Jewish]

Most people who had the Bacille Calmette-Guerin (BCG) vaccine as a child do not react positively to purified protein derivative (PPD) tuberculin skin test as an adult.  So an adult with a positive PPD may have been infected with tuberculosis (TB).  The likelihood is higher if they are at risk as a health care worker or have other exposures.  We don't believe that a childhood BCG protects against adult TB.  So we would treat this person with INH preventive therapy.

[sshr23]

where can I find more resources?

[Ellis7]

You can find info by searching with google.com on 'tuberculosis ppd bcg'   For example:

http://www.pamf.org/patients/bcg_ppd.html
Understanding Positive PPD Skin Tests after BCG Vaccination
Excerpts:
"Most adults who received BCG before age 7 who have a positive PPD skin test after age 21 have the tuberculosis germ in their bodies. This positive reaction is NOT usually because of BCG they received as a child.

If you have a positive PPD skin test, you should get a chest X-ray to look for active tuberculosis, since this germ most commonly affects the lungs. You also should report any symptoms that suggesting active tuberculosis. These symptoms include long standing cough, sweating at night or unexplained weight loss. If there is no cough and the chest xray is normal, then the condition is not likely to be contagious and won't be spread to others.

If you have none of these symptoms and have a normal chest X-ray, then you are not considered contagious and you are able to work or volunteer normally. Your doctor can write a note confirming this for anyone who needs this information

As people get older, the tuberculosis germ can become active, start to grow and cause illness. Without preventive medication, 15 out of 100 people (15%) with a positive PPD will develop active tuberculosis at some time. With medication, only three in 100 people (3%) with a positive PPD will develop active tuberculosis.

If you have a positive PPD and normal chest xray, your doctor may recommend that you take medicine to prevent the tuberculosis from becoming active and making you sick. Medication, usually isoniazid (INH), is taken daily for nine months to prevent future symptoms of tuberculosis. While INH is generally quite safe, it can cause temporary changes in the liver.

Please talk with your doctor about your risks of developing tuberculosis symptoms and the possible benefits of medication to prevent illness in the future.
Last updated: 2/2003
Palo Alto Medical Foundation

[sshr23]

Could u please suggest any articles on research done in this area. Full article

Is it just the opinion? as was given in article retrieved by google?

[Ellis7]

Info from the National Inst of Health [US gov]:
http://www.nlm.nih.gov/medlineplus/tuberculosis.html

http://www.niaid.nih.gov/factsheets/tb.htm
Nat Inst of Allergy & Infectious Disease
Tuberculosis              March 2002
Excerpts:
"How is TB diagnosed?

Doctors can identify most people infected with M. tuberculosis with a skin test. They will inject a substance under the skin of the forearm. If a red welt forms around the injection site within 72 hours, the person may have been infected. This doesn't necessarily mean he or she has active disease. Most people with previous exposure to M. tuberculosis will test positive on the tuberculin test, as will some people exposed to bacteria that are related to the TB germ.

If a person has an obvious reaction to the skin test, other methods can help to show if the individual has active TB. In making a diagnosis, doctors rely on symptoms and other physical signs, a person's history of exposure to TB, and x-rays that may show evidence of M. tuberculosis infection.

The doctor also will take sputum and other samples, to see if the TB bacteria will grow in the lab. If bacteria are growing, this positive culture confirms the diagnosis of TB. Because M. tuberculosis grows very slowly, it can take four weeks to confirm the diagnosis. An additional two to three weeks usually are needed to determine which antibiotics the bacteria are susceptible to.
...................
Is there a vaccine for TB?

In those parts of the world where the disease is common, the World Health Organization (WHO) recommends that infants receive a vaccine called BCG made from a live weakened bacterium related to M. tuberculosis. BCG vaccine prevents M. tuberculosis from spreading within the body, thus preventing TB from developing.

However, the vaccine has its drawbacks. It does not protect adults very well against TB. In addition, BCG interferes with the TB skin test, showing a positive skin test reaction in people who have received BCG vaccine. In countries where BCG vaccine is used, the ability of the skin test to identify persons that are infected with M. tuberculosis is limited. Because of these limitations, more effective vaccines are needed and BCG is not recommended for general use in the United States."
---------------------------

[Ellis7]

From PubMed:
1: Int J Tuberc Lung Dis. 2003 Apr;7(4):320-6.
                                                                
Tuberculin reactivity in adult BCG-vaccinated subjects: a cross-sectional study.

Bugiani M, Borraccino A, Migliore E, Carosso A, Piccioni P, Cavallero M, Caria E, Salamina G, Arossa W.

Pneumology Unit, Consorzio Provinciale Antitubercolare, Azienda Sanitaria Locale 4, Piedmont, Turin, Italy. ***@****
Excerpt:

INTRODUCTION: Interpretation of the tuberculin skin test (TST) may be complicated by prior bacille Calmette-Guerin (BCG) vaccination. The skin reaction to the vaccination interferes with the management of individuals who may be infected with Mycobacterium tuberculosis...............
............
RESULTS: The risk of being a contact versus BCG-vaccinated increases 2.43-fold with every mm of TST diameter. The 11 mm cut-off point seems to be the best discriminating value. CONCLUSIONS: Using the traditional 10 mm cut-off, we can consider all vaccinated subjects with a positive TST to be infected. The TST remains a valuable tool for the evaluation of household contacts and suspected cases of tuberculosis in BCG-vaccinated subjects and in populations with high vaccination coverage."

PMID: 12729336 [PubMed - indexed for MEDLINE]

[Ellis7]

http://ajrccm.atsjournals.org/cgi/content/full/170/1/65
American Journal of Respiratory and Critical Care Medicine Vol 170. pp. 65-69, (2004) © 2004 American Thoracic Society

Comparison of Tuberculin Skin Test and New Specific Blood
Test in Tuberculosis Contacts

Inger Brock, Karin Weldingh, Troels Lillebaek, Frank Follmann and Peter Andersen

Department of Infectious Disease Immunology, Statens Serum Institute; and International Reference Laboratory of Mycobacteriology, Statens Serum Institute, Copenhagen, Denmark
Excerpt:
"The tuberculin skin test used to detect latent Mycobacterium tuberculosis infection has many drawbacks, and a new
diagnostic test for latent tuberculosis (QuantiFERON-TB [QTF-TB]) has recently been introduced. This test measures the
production of IFN- in whole blood upon stimulation with purified protein derivative (PPD). The QTF-TB test addresses
the operational problems with the tuberculin skin test, but, as the test is based on PPD, it still has a low specificity in
populations vaccinated with the Bacile Calmette-Guérin (BCG) vaccine. We have modified the test to include the antigens
ESAT-6 and CFP-10, which are not present in BCG vaccine strains or the vast majority of nontuberculous mycobacteria. This test was used to detect infection in contacts in a tuberculosis outbreak at a Danish high school. The majority of the contacts were BCG-unvaccinated, which allowed a direct comparison of the skin test and the novel blood test in individuals whose skin test was not confounded by vaccination. An excellent agreement between the two tests was found (94%,  value 0.866), and in contrast to the blood test based on PPD, the novel blood test was not influenced by the vaccination status of the subjects tested. "