Latent tuberculosis infection: Difference between revisions
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= Definition = |
== Definition == |
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* Prior exposure to TB |
* Prior exposure to TB |
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* Goal is to identify those who are at increased risk of developing active TB and would benefit from treatment |
* Goal is to identify those who are at increased risk of developing active TB and would benefit from treatment |
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= Investigations = |
== Investigations == |
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* Tuberculin skin test (TBST) |
* Tuberculin skin test (TBST) |
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** Preferred for those who have received BCG after infancy |
** Preferred for those who have received BCG after infancy |
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= Positive TBST = |
== Positive TBST == |
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# Is it truly positive? |
# Is it truly positive? |
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#* baseline liver enzymes and vision testing |
#* baseline liver enzymes and vision testing |
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= Further Reading = |
== Further Reading == |
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* [http://blogs.jwatch.org/hiv-id-observations/index.php/common-curbsides-the-tuberculin-skin-test-and-igra-that-dont-agree/2014/11/10/ TBST vs. IGRA for latent TB] |
* [http://blogs.jwatch.org/hiv-id-observations/index.php/common-curbsides-the-tuberculin-skin-test-and-igra-that-dont-agree/2014/11/10/ TBST vs. IGRA for latent TB] |
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= Tools = |
== Tools == |
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* [http://www.tstin3d.com/en/calc.html TST in 3D online TBST/IGRA Interpreter] |
* [http://www.tstin3d.com/en/calc.html TST in 3D online TBST/IGRA Interpreter] |
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Revision as of 15:23, 17 August 2019
Definition
- Prior exposure to TB
- Goal is to identify those who are at increased risk of developing active TB and would benefit from treatment
Investigations
- Tuberculin skin test (TBST)
- Sens 90%, Spec >95
- Interferon-gamma release assay (IGRA)
- Sn 95%, Sp >95%
- Preferred for those who have received BCG after infancy
Positive TBST
- Is it truly positive?
- Consider IGRA
- BCG vaccine can be considered a cause of false positive when
- vaccine given after 12 months of age, and
- patient has no risk factors, and
- either Canadian-born non-Aboriginal, or not from endemic country
- Rule out active TB
- signs/symptoms
- CXR or CT chest
- Sputum x3 if coughing or cavitary lesions
- Evaluate risk of reactivation treatment
- INH 300 daily x9 mo with pyridoxine
- baseline liver enzymes and vision testing
Further Reading
Tools
References
- ^ Canadian Tuberculosis Standards. 7th edition. ed. Template:ISBN. OCLC 978699031.
- ^ Dick Menzies, Menonli Adjobimey, Rovina Ruslami, Anete Trajman, Oumou Sow, Heejin Kim, Joseph Obeng Baah, Guy B. Marks, Richard Long, Vernon Hoeppner, Kevin Elwood, Hamdan Al-Jahdali, Martin Gninafon, Lika Apriani, Raspati C. Koesoemadinata, Afranio Kritski, Valeria Rolla, Boubacar Bah, Alioune Camara, Isaac Boakye, Victoria J. Cook, Hazel Goldberg, Chantal Valiquette, Karen Hornby, Marie-Josée Dion, Pei-Zhi Li, Philip C. Hill, Kevin Schwartzman, Andrea Benedetti. Four Months of Rifampin or Nine Months of Isoniazid for Latent Tuberculosis in Adults. New England Journal of Medicine. 2018;379(5):440-453. doi:10.1056/nejmoa1714283.
