targeted tuberculin testing and treatment of latent tuberculosis infection pdf

Targeted Tuberculin Testing And Treatment Of Latent Tuberculosis Infection Pdf

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Madhukar Pai and Philip Hopewell. Produced by the WHO. Surveillance of tuberculosis in Europe [].

Targeted Tuberculin Testing and Treatment of Latent Tuberculosis Infection

Latent tuberculosis infection LTBI is the persistence of an immunological response to Mycobacterium tuberculosis antigen stimulation without any clinically active disease.

To control the active infection, the shrinking of the magnitude of the pool of latent infection is required. There has been a lot of emphasis in the past few decades on the elimination of TB. While treatment of active disease is by far the major intervention in this regard, LTB treatment forms an important yet undervalued facet.

The diagnosis and treatment of LTBI are hindered by the cost implications of testing, lack of a consensus on the tests recommended, and side effects of treatment. Treatment of LTBI in low prevalence high to upper-middle-income countries is feasible, as elimination of this reservoir of infection will reduce the burden of the disease.

However, the scenario in high prevalence countries such as India is quite the opposite. Here, reinfection due to contact with active cases rather than reactivation contributes to a high disease burden.

This is the reason for the absence of a nationwide policy on LTBI treatment. In such a situation, LTBI treatment needs to be individualized.

Preference should be given to those at high risk of reactivation, especially due to the short term reversible predisposing factor. Hence, the decision to treat LTBI should be taken by considering the probability of reactivation versus reinfection. The last review of this topic was done in India by Agarwal in In this review, we will focus on current evidence of LTBI testing and treatment in high incidence countries such as India.

TST identifies people with the previous sensitization to tubercular antigens by stimulating a delayed-type hypersensitivity reaction. Time to positivity varies from 2 to 8 weeks after exposure. Interpretation of TST is based on the pre-test probability, patient profile, and setting in which the test has been performed.

Cutoffs of 5, 10, and 15 mm are used. Higher cutoff increases the specificity but decreases the sensitivity of the test. Thus, the high cutoff is useful in low prevalence settings, and in those with high nontubercular mycobacterium NTM exposure.

The effect of vaccination on TST positivity varies with time of vaccination. The role of NTM in positivity is significant only in developed countries with low incidence and prevalence of TB. Those with baseline positivity within 2. If negative, a second test is performed at 8 weeks after the end of the exposure.

There is modest variability in the results, which increases at either end of the spectrum. Immunosuppressed patients and HIV positive are more likely to have indeterminate results [ Table 1 ]. This test has fared well in Phase 3, double-blinded, and randomized trial published in Testing for LTBI should only be done in those who are likely to have the infection.

Before testing, all patients must be systematically investigated for the active tuberculous disease. It takes into consideration the risk of infection, the likelihood of progression of the disease, and the likely benefit of therapy. However, the two tests may be complementary to each other in improving the sensitivity and specificity of the results [ 13 , 14 ].

This includes HIV, contacts of active cases, patients on dialysis, antitumor necrosis factor TNF therapy, and immunosuppressed, patients with silicosis those living in close conditions include prisons and nursing homes. It is a well-known fact that people on immunosuppressant drugs such as steroids, biologicals, disease-modifying antirheumatic drugs, and other antirheumatic drugs have a greater risk of developing TB than the general population. For the rest, either test can be used.

Repeat testing is recommended in immunosuppressed, and those with high-risk conditions as given by the CDC. After at least 1 month of treatment, biological can be given. If biological therapy must be continued, then LTBI screening may be considered on an annual basis if the patient initially tested negative. In India, although a large number of patients suffer from rheumatic diseases, there are no clear guidelines for LTBI testing and treatment.

The value of TST is doubted, due to false negativity in immunosuppressed patients, and false positivity due to BCG vaccination. Even in populations with low TB incidence, TST becomes positive after stopping steroids for at least 1 month and after 3 months with other immunosuppressants.

This is the current practice at most rheumatology centres. Those with radiographic scarring without anti-tubercular treatment ATT intake and those with inadequate ATT intake in the past should be offered chemoprophylaxis. Patients with adequately treated TB in the past may be kept under close monitoring with 3 monthly radiographs. There is a conditional recommendation to give 6 months IPT in children after completion of chemotherapy for active TB. In all subsets, at least 6 months of IPT is preferred.

In high burden countries, 36 months of IPT can be considered in lieu of lifelong therapy. At every contact with the patient, screening for TB must be done. The treatment should be given to: Asymptomatic contacts under 6 years of age of a smear-positive case, without evidence of active disease, should be given in regardless of their TST, BCG, or nutritional status. TST positive children planned for or receiving immunosuppression e. A child born to TB positive mother if there is no evidence of congenital TB in the new-born.

This is in keeping with the ACR guidelines. However, due to lack of clear cut guidelines for India, treatment in other cases such as immunosuppressed and close contacts of active cases are done on a case to case basis. In most studies conducted to date, all the above regimens were non-superior to each other. However, on a case to case basis, some regimens may be preferred over others.

In others, these may be preferred as they are shorter and patients are likely to be more compliant. However, cost implications must be considered as well. TB is a major burden in our nation. The selection of the LTBI subgroup requiring management is an under-learn aspect of comprehensive patient care. This must be offered to high-risk individuals.

Currently, LTBI treatment is recommended in children below 6 years of age who are contacts of smear-positive cases, born to mothers with TB, are immunosuppressed with TST positive, or in contact with active TB cases. In adults with HIV, a personalized approach to care is taken. However, the benefit of treatment may be more in those with TST positivity.

While the results of treating LTBI at a nationwide level may not be evident in the short run, it will decrease the reservoir of infection which will impact future elimination efforts. Being a high burden country, such data are highly relevant.

We also need to identify other high-risk subgroups where LTBI treatment may be warranted. The complex nature of the disease and various socioeconomic factors mandates further research in this area. Skip to content. Share Tweet Share. Review Article. Current status of treatment of latent tuberculosis infection in India. Saha 1 , A. Saurabh 2 , S. Shankar 1 , A. Kashyap 1 , N. Nischal 1 , A. Biswas 1 , N. Wig 1. Indian J Med Sci ;71 2 Abstract In view of the high burden of latency of tuberculosis TB in India, tackling latent TB in the right way is a menace.

However, this approach cannot be implemented in high burden countries like India until concrete evidence or consensus by experts on this subject is made. There are very specific risk groups where these patients are to be treated as far as current evidence-based medicine is concerned.

Hence, the need to develop a document was felt, through which the treatment of LTBI becomes homogeneous by each and every physician who is practicing and treating TB. The last attempt to review the topic was made in , after which there have been many changes and update in this subject. Keywords Latent tuberculosis infection. Show Related Articles from PubMed. In the Indian context, tuberculin skin test may be preferred over interferon-gamma release assay refer text.

Export to PPT. Figure Algorithm for the testing and treatment of latent tuberculosis infection. Eur Respir J. Consensus statement. Global burden of tuberculosis: Estimated incidence, prevalence, and mortality by country. World Health Organization. The prognosis of a positive tuberculin reaction in childhood and adolescence.

Am J Epidemiol. Health AGD. Tuberculosis: A Comprehensive International Approach 2nd ed. Latent tuberculosis in children: Diagnosis and management. Indian J Pediatr. Agarwal R.

Targeted TB Testing and Treatment of Latent TB Infection (LTBI)

Latent tuberculosis infection LTBI is the persistence of an immunological response to Mycobacterium tuberculosis antigen stimulation without any clinically active disease. To control the active infection, the shrinking of the magnitude of the pool of latent infection is required. There has been a lot of emphasis in the past few decades on the elimination of TB. While treatment of active disease is by far the major intervention in this regard, LTB treatment forms an important yet undervalued facet. The diagnosis and treatment of LTBI are hindered by the cost implications of testing, lack of a consensus on the tests recommended, and side effects of treatment. Treatment of LTBI in low prevalence high to upper-middle-income countries is feasible, as elimination of this reservoir of infection will reduce the burden of the disease.

Targeted TB Testing and Treatment of Latent TB Infection (LTBI)

The treatment of latent tuberculosis infection LTBI is an essential component of tuberculosis TB elimination in regions that have a low incidence of TB. However, the decision to treat individuals with LTBI must consider the limitations of current diagnostic tests for LTBI, the risk of developing active TB disease, the potential adverse effects from chemoprophylactic therapy, and the importance of treatment adherence. When an individual has been diagnosed with LTBI and active TB has been ruled out, this is followed by an evaluation of the risks and benefits of LTBI treatment within the context of the regional epidemiology of TB and public health priorities. As the duration of treatment of LTBI therapy is many months, therapy must be offered within a plan that monitors for adverse drug reactions and emphasizes adherence. For latent multidrug-resistant TB MDR-TB or extensively drug-resistant TB XDR-TB infection, the management is more complicated as there are few options for chemoprophylactic therapy and little evidence regarding the efficacy or risks of these regimens.

TB Diagnostic Reference Documents

David L.

David L. New recommendations for targeted tuberculin testing and treatment of latent tuberculosis TB infection have recently been published. Changes in nomenclature from screening to targeted tuberculin testing and from preventive therapy to treatment of latent TB infection LTBI are intended to promote more widespread implementation by programs and health care providers. Targeted tuberculin testing is designed to identify persons at high risk for TB and is discouraged for persons at low risk.

FERN R. Related Editorial. Patient information: See related handout on tuberculosis , written by the authors of this article. Latent tuberculosis infection LTBI is a condition in which a person is infected with Mycobacterium tuberculosis , but does not currently have active tuberculosis disease. Because 5 to 10 percent of persons with LTBI are at risk of progressing to active disease, identification and treatment of LTBI are essential for the elimination of tuberculosis.

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