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New TB Guidelines

New TB Guidelines. Deborah McMahan, MD Health Commissioner Fort Wayne Allen County Department of Health. Agenda. Diagnosis of: Latent TB infection (LTBI) Pulmonary tuberculosis Extrapulmonary tuberculosis. Diagnosis of LTBI. Latent TB.

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New TB Guidelines

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  1. New TB Guidelines Deborah McMahan, MD Health Commissioner Fort Wayne Allen County Department of Health

  2. Agenda Diagnosis of: • Latent TB infection (LTBI) • Pulmonary tuberculosis • Extrapulmonary tuberculosis

  3. Diagnosis of LTBI

  4. Latent TB • The purpose of testing for latent TB infection (LTBI) is to identify folks who should be treated to prevent reactivation at a later date. • There are 2 major benefits of treating LTBI: • Treating LTBI prevents progression to active TB disease in the individual. • Prevents transmission (each active case infects 15 people on average before identified and started on tx. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  5. Latent TB • Average person with latent TB has a about a 5% to 10% chance of developing active TB. •  The greatest risk of progression is during the first 2 years following exposure to an active case. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  6. Latent TB •  Relative risk measures the strength of association between an exposure and a disease.  If the relative risk result is: • <1 the exposure decreases risk of disease • 0 the exposure has no effect on risk of disease • >1 the exposure increases risk of disease

  7. Risk Factors for Progression • Advanced untreated HIV 10 • Close contacts 6.1 • Old unhealed TB on x-ray 5.2 • Treatment with TNF-α inhibitor 2 • Diabetes uncontrolled 1.7 • Silicosis 2.8 https://static1.squarespace.com/static/52c5f4ade4b02052b13a2eac/t/53253ac1e4b08fd5fbc4479b/1394948801465/LTBI+rv+nejm+2011.pdf

  8. Risk Factors for Progression Other risk factors include: • Age less than 4 years • Smoking • Low body weight • Renal failure • Transplant • Prednisone treatment at doses of 15 mg/day for more than 1 month https://static1.squarespace.com/static/52c5f4ade4b02052b13a2eac/t/53253ac1e4b08fd5fbc4479b/1394948801465/LTBI+rv+nejm+2011.pdf

  9. Definitions • Sensitivity is the ability of a test to correctly identify those with the disease (true positive rate) • Specificity is the ability of the test to correctly identify those without the disease (true negative rate).

  10. Definitions • Positive predictive value is the probability that subjects with a positive screening test truly have the disease. • Negative predictive value is the probability that subjects with a negative screening test truly don't have the disease. http://sphweb.bumc.bu.edu/otlt/MPH-Modules/EP/EP713_Screening/EP713_Screening5.html

  11. Diagnosis of Latent TB Tuberculin skin Test • Sensitivity is high (95%–98%). • False-negative reactions occur more frequently in: • Infants and young children • Early (<6–8 weeks) after infection • Persons having recently received viral vaccination • Persons with clinical conditions associated with immunosuppression or overwhelming illness (including TB) • Persons with recent viral and bacterial infections • Association with treatment with immunosuppressive drugs (eg, high-dose corticosteroids, TNF inhibitors). https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  12. Diagnosis of Latent TB Tuberculin skin Test • The specificity is 29 to 39% • The positive predictive value 2.7 to 3.1% • The negative predictive value 99 to 100% https://static1.squarespace.com/static/52c5f4ade4b02052b13a2eac/t/53253ac1e4b08fd5fbc4479b/1394948801465/LTBI+rv+nejm+2011.pdf

  13. Diagnosis of Latent TB - IGRAs • IGRAs use asingle specimen of peripheral blood that is drawn and incubated overnight with specific antigens for M. tuberculosis; interferon-γ production is then determined. • The QFT test measures the amount of interferon-γ in the supernatant of a cell suspension, whereas the T-SPOT test determines the number of cells producing interferon-γ with the use of an ELISpot assay. https://static1.squarespace.com/static/52c5f4ade4b02052b13a2eac/t/53253ac1e4b08fd5fbc4479b/1394948801465/LTBI+rv+nejm+2011.pdf

  14. Diagnosis of Latent TB IGRAs • The pooled sensitivity of IGRAs for predicting the development of active disease within several years after exposure was 80 to 90%, • The specificity 56 to 83% • The positive predictive value 4 to 8% • The negative predictive value 99 to 100%. https://static1.squarespace.com/static/52c5f4ade4b02052b13a2eac/t/53253ac1e4b08fd5fbc4479b/1394948801465/LTBI+rv+nejm+2011.pdf

  15. Diagnosis of Latent TB - IGRAs • IGRAs appear to be somewhat more specific and less sensitive for predicting future disease than the tuberculin skin test, but the differences are modest. • Both types of test have low positive and high negative predictive values. • Because both IGRAs and the TST rely on an intact immune response, both are likely to have reduced sensitivity when used in persons with immunosuppression. https://static1.squarespace.com/static/52c5f4ade4b02052b13a2eac/t/53253ac1e4b08fd5fbc4479b/1394948801465/LTBI+rv+nejm+2011.pdf

  16. Diagnosis of Latent TB - IGRAs • Whereas the tuberculin skin test may be more likely to identify persons with longstanding cellular immune responses to TB antigens, IGRAs are more likely to be positive in persons who have recently been infected with M. tuberculosis, which is a group at particularly high risk for progression to disease. • Also no cross reactivity with BCG https://static1.squarespace.com/static/52c5f4ade4b02052b13a2eac/t/53253ac1e4b08fd5fbc4479b/1394948801465/LTBI+rv+nejm+2011.pdf

  17. Diagnosis of Latent TB • Remember, A negative reaction to a TST or IGRA does not exclude the diagnosis of LTBI or TB disease. • The decisions about medical or public health management should include epidemiological, historical, and other clinical information when using IGRA or TST results. • Decisions should not be based on TST or IGRA results alone. https://static1.squarespace.com/static/52c5f4ade4b02052b13a2eac/t/53253ac1e4b08fd5fbc4479b/1394948801465/LTBI+rv+nejm+2011.pdf

  18. Guideline Development Methodology

  19. Methodology • American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America searched, selected, and synthesized relevant evidence to draft recommendations that were then graded by the group. • David M. Lewinsohn Michael K. Leonard Philip A. LoBue David L. Cohn Charles L. Daley Ed Desmond Joseph Keane Deborah A. Lewinsohn Ann M. Loeffler Gerald H. Mazurek Richard J. O’Brien MadhukarPai Luca Richeldi Max Salfinger Thomas M. Shinnick Timothy R. Sterling David M. Warshauer Gail L. Woods https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  20. Methodology They used the GRADE approach • Grading • Recommendations • Assessment • Development • Evaluation https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  21. Strong Recommendation Patient Perspective: Most individuals in this situation would want the recommended course of action, and only a small proportion would not.  Clinician Perspective: Most individuals should receive the intervention. Adherence to this recommendation according to the guideline could be used as a quality criterion or performance indicator. Formal decision aids are not likely to be needed to help individuals make decisions consistent with their values and preferences.  Policy: The recommendation can be adopted as policy in most situations.  https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  22. Conditional (Weak) Recommendation Patient Perspective: The majority of individuals in this situation would want the suggested course of action, but many would not.  Clinician Perspective: Recognize that different choices will be appropriate for individual patients and that you must help each patient arrive at a management decision consistent with his or her values and preferences. Decision aids may be useful in helping individuals to make decisions consistent with their values and preferences.  Policy: Policymaking will require substantial debate and involvement of various stakeholders.  https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  23. Methodology Recommendations were made for diagnosing: • Latent TB infection (LTBI) • Pulmonary tuberculosis • Extrapulmonary tuberculosis Their recommendations for diagnostic testing for LTBI are based upon the likelihood of infection with Mtb and the likelihood of progression to TB disease if infected https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  24. High Risk for Infection • Close contacts to an active case • Immigrants from high prevalence countries • Homeless • Injection Drug Users https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  25. Risk for Progression to Disease Low Risk – No Risk Factors Intermediate Risk (RR 1.3 to 3): Clinical predisposition: • Diabetes • Chronic renal failure • IVDU https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  26. Risk for Progression to Disease High Risk (RR 3 to 10): • Children less than 5 years of age • HIV • Immunosuppressive therapy • Chest x-ray consistent with prior infection • Silicosis https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  27. Guidelines for Testing for Latent TB Infection

  28. Strong Recommendation They recommend performing an IGRA rather than a TST in individuals 5 years or older who meet the following criteria: • are likely to be infected with Mtb • have a low or intermediate risk of disease progression • it has been decided that testing for LTBI is warranted • either have a history of BCG vaccination or are unlikely to return to have their TST read Remarks: A TST is an acceptable alternative, especially in situations where an IGRA is not available, too costly, or too burdensome. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  29. Conditional Recommendation They suggest performing an IGRA rather than a TST in all other individuals 5 years or older who are: • likely to be infected with Mtb • who have a low or intermediate risk of disease progression • and in whom it has been decided that testing for LTBI is warranted Remarks: A TST is an acceptable alternative, especially in situations where an IGRA is not available, too costly, or too burdensome. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  30. Insufficient Data There are insufficient data to recommend a preference for either a TST or an IGRA as the first-line diagnostic test in individuals 5 years or older who are: • likely to be infected with Mtb • who have a high risk of progression to disease • in whom it has been determined that diagnostic testing for LTBI is warranted. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  31. Conditional Recommendation Testing of people with low risk of being infected and disease progression but are required to be tested for job, etc. They suggest performing an IGRA instead of a TST in individuals 5 years or older Remarks: A TST is an acceptable alternative in settings where an IGRA is unavailable, too costly, or too burdensome. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  32. Conditional Recommendation They suggest a second diagnostic test if the initial test is positive in individuals 5 years or older Remarks: The confirmatory test may be either an IGRA or a TST. When such testing is performed, the person is considered infected only if both tests are positive. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  33. Conditional Recommendation They suggest performing a TST rather than an IGRA in healthy children <5 years of age for whom it has been decided that diagnostic testing for LTBI is warranted Remarks: In situations in which an IGRA is deemed the preferred diagnostic test, some experts are willing to use IGRAs in children over 3 years of age. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  34. Conditional Recommendation They suggest performing a TST rather than an IGRA in healthy children <5 years of age for whom it has been decided that diagnostic testing for LTBI is warranted Remarks: In situations in which an IGRA is deemed the preferred diagnostic test, some experts are willing to use IGRAs in children over 3 years of age. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  35. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectioushttps://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  36. World TB Day Quizlet • 45 year old Phillippino presents for green card physical. His Past Medical History is remarkable for hypertension and chronic renal failure. He has no symptoms but his shoe size is 11 medium. • What test do you recommend for evaluating for LTBI? IGRA; high risk of infection and intermediate risk for progression

  37. World TB Day Quizlet • Eighteen year old girl whose grandmother was diagnosed with smear positive active TB. No symptoms but does not seem to like you very much and she is homeless • What test do you recommend for evaluating for LTBI? IGRA; high risk of infection and intermediate risk for progression but not likely to return

  38. Guidelines for Testing for Active TB Disease

  39. Strong Recommendation We recommend that acid-fast bacilli (AFB) smear microscopy be performed, rather than no AFB smear microscopy, in all patients suspected of having pulmonary TB. Providers should request a sputum volume of at least 3 mL, but the optimal volume is 5–10 mL. Concentrated respiratory specimens and fluorescence microscopy are preferred. Remarks: False-negative results are sufficiently common that a negative AFB smear result does not exclude pulmonary TB. Similarly, false-positive results are sufficiently common that a positive AFB smear result does not confirm pulmonary TB. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  40. Conditional Recommendation They suggest that both liquid and solid mycobacterial cultures be performed, rather than either culture method alone, for every specimen obtained from an individual with suspected TB disease (conditional recommendation, low-quality evidence). Remarks: The conditional qualifier applies to performance of both liquid and solid culture methods on all specimens. At least liquid culture should be done on all specimens as culture is the gold standard microbiologic test for the diagnosis of TB disease. The isolate recovered should be identified according to the Clinical and Laboratory Standards Institute guidelines and the American Society for Microbiology Manual of Clinical Microbiology. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  41. Mycobacterium tuberculosis colonies on Löwenstein-Jensen solid medium TB growth in liquid medium

  42. Conditional Recommendation They suggest performing a diagnostic nucleic acid amplification test (NAAT), rather than not performing a NAAT, on the initial respiratory specimen from patients suspected of having pulmonary TB. Remarks: In AFB smear-positive patients, a negative NAAT makes TB disease unlikely. In AFB smear-negative patients with an intermediate to high level of suspicion for disease, a positive NAAT can be used as presumptive evidence of TB disease, but a negative NAAT cannot be used to exclude pulmonary TB. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  43. Strong Recommendation They recommend performing rapid molecular drug susceptibility testing for rifampin with or without isoniazid using the respiratory specimens of persons who are either AFB smear positive or Hologic Amplified MTD positive and who meet one of the following criteria: • have been treated for tuberculosis in the past, • were born in or have lived for at least 1 year in a foreign country with at least a moderate tuberculosis incidence (≥20 per 100 000) or a high primary multidrug-resistant tuberculosis prevalence (≥2%) • are contacts of patients with multidrug-resistant tuberculosis, or • are HIV infected. Remarks: This recommendation specifically addresses patients who are Hologic Amplified MTD positive because the Hologic Amplified MTD NAAT only detects TB and not drug resistance; it is not applicable to patients who are positive for types of NAAT that detect drug resistance, including many line probe assays and Cepheid Xpert MTB/RIF. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  44. Molecular Drug Susceptibility • The test simultaneously detects Mycobacterium tuberculosis complex (MTBC) and resistance to rifampin (RIF) in less than 2 hours. • In comparison, standard cultures can take 2 to 6 weeks for MTBC to grow and conventional drug resistance tests can add 3 more weeks. • Quicker results provide timely that aids in selecting treatment regimens and reaching infection control decisions quickly. https://www.cdc.gov/tb/publications/factsheets/pdf/xpertmtb-rifassayfactsheet_final.pdf

  45. Conditional Recommendation They suggest mycobacterial culture of respiratory specimens for all children suspected of having pulmonary TB. Remarks: In a low incidence setting like the United States, it is unlikely that a child identified during a recent contract investigation of a close adult/adolescent contact with contagious TB was, in fact, infected by a different individual with a strain with a different susceptibility pattern. Therefore, under some circumstances, microbiological confirmation may not be necessary for children with uncomplicated pulmonary TB identified through a recent contact investigation if the source case has drug- susceptible TB. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  46. Conditional Recommendation They suggest sputum induction rather than flexible bronchoscopic sampling as the initial respiratory sampling method for adults with suspected pulmonary TB who are either unable to expectorate sputum or whose expectorated sputum is AFB smear microscopy negative https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  47. Conditional Recommendation They suggest flexible bronchoscopic sampling, rather than no bronchoscopic sampling, in adults with suspected pulmonary TB from whom a respiratory sample cannot be obtained via induced sputum. Remarks: In the committee members’ clinical practices, bronchoalveolar lavage (BAL) plus brushings alone are performed for most patients; however, for patients in whom a rapid diagnosis is essential, transbronchial biopsy is also performed. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

  48. What is a NAAT? • Nucleic acid amplification test (NAAT) is a testing method that detects the genetic material (nucleic acid) of the bacteria causing the infection. • It does this in part by amplifying or making numerous copies of the genetic material so that the detection system can identify the presence of the bacteria. 

  49. Conditional Recommendation They suggest that postbronchoscopy sputum specimens be collected from all adults with suspected pulmonary TB who undergo bronchoscopy. Remarks:Postbronchoscopy sputum specimens are used to perform AFB smear microscopy and mycobacterial cultures. https://academic.oup.com/cid/article/doi/10.1093/cid/ciw694/2629583/Official-American-Thoracic-Society-Infectious

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