Latent tuberculosis infection: Difference between revisions
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* Prior exposure to TB leading to persistent latent tuberculosis, usually contained within lung ganulomas |
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== Definition == |
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* 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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** 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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#* INH 300 daily x9 mo with pyridoxine |
#* INH 300 daily x9 mo with pyridoxine |
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#* baseline liver enzymes and vision testing |
#* baseline liver enzymes and vision testing |
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== Management == |
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* Standard regimen (9INH): |
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** Nine months of isoniazid with daily vitamin B6 |
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* Alternative shorter courses: |
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** 6INH |
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** 3-4INH/RMP |
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** 4RIF, maybe |
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== Further Reading == |
== Further Reading == |
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Revision as of 17:36, 18 September 2019
- Prior exposure to TB leading to persistent latent tuberculosis, usually contained within lung ganulomas
- 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
Management
- Standard regimen (9INH):
- Nine months of isoniazid with daily vitamin B6
- Alternative shorter courses:
- 6INH
- 3-4INH/RMP
- 4RIF, maybe
Further Reading
Tools
References
- a b c Tasnim Hasan, Eric Au, Sharon Chen, Allison Tong, Germaine Wong. Screening and prevention for latent tuberculosis in immunosuppressed patients at risk for tuberculosis: a systematic review of clinical practice guidelines. BMJ Open. 2018;8(9):e022445. doi:10.1136/bmjopen-2018-022445.
