Mycobacterium tuberculosis: Difference between revisions
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Mycobacterium tuberculosis
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* Standard treatment for susceptible TB is '''RIPE x2mo then RI x4mo''' |
* Standard treatment for susceptible TB is '''RIPE x2mo then RI x4mo''' |
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| − | == |
+ | == Background == |
| + | === Microbiology === |
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| + | * Fastidious [[Has Gram stain::Acid-fast]] [[Has shape::bacillus]] |
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* Reinfection accounts for ~40% of active tuberculosis in endemic countries |
* Reinfection accounts for ~40% of active tuberculosis in endemic countries |
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* Latent tuberculosis in ~30% of the global population |
* Latent tuberculosis in ~30% of the global population |
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== Clinical Presentation == |
== Clinical Presentation == |
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| + | === Classification === |
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=== Primary tuberculosis === |
=== Primary tuberculosis === |
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* Primary tuberculosis is usually asymptomatic |
* Primary tuberculosis is usually asymptomatic |
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* Possible presentations include mild URTI with cough and/or fever |
* Possible presentations include mild URTI with cough and/or fever |
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=== Pulmonary tuberculosis === |
=== Pulmonary tuberculosis === |
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* Subacute or [[chronic cough]] (at least 2 to 3 weeks) eventually becoming productive and occasionally involving [[hemoptysis]] |
* Subacute or [[chronic cough]] (at least 2 to 3 weeks) eventually becoming productive and occasionally involving [[hemoptysis]] |
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** Should be suspected in any patient with '''cough and [[HIV]] infection''' |
** Should be suspected in any patient with '''cough and [[HIV]] infection''' |
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=== Extra-pulmonary tuberculosis === |
=== Extra-pulmonary tuberculosis === |
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* Pleural tuberculosis is most common extrapulmonary site |
* Pleural tuberculosis is most common extrapulmonary site |
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* [[Scrofula]] (cervical lymph node infection) next-most common |
* [[Scrofula]] (cervical lymph node infection) next-most common |
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=== Latent tuberculosis === |
=== Latent tuberculosis === |
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* Refers to chronic latent infection contained within granulomas that may reactivate in the future |
* Refers to chronic latent infection contained within granulomas that may reactivate in the future |
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* Refer to [[Latent tuberculosis infection]] |
* Refer to [[Latent tuberculosis infection]] |
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== Investigations == |
== Investigations == |
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* Radiography: chest x-ray with or without CT chest |
* Radiography: chest x-ray with or without CT chest |
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* Microbiology: |
* Microbiology: |
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== Management == |
== Management == |
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* Standard HREZ x2mo then HR x4mo |
* Standard HREZ x2mo then HR x4mo |
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** Isoniazid 5mg/kg/d, max 300mg daily |
** Isoniazid 5mg/kg/d, max 300mg daily |
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=== DILI === |
=== DILI === |
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* Most common complication leading to treatment interruption, with a mortality of 6-12% if drugs are not stopped |
* Most common complication leading to treatment interruption, with a mortality of 6-12% if drugs are not stopped |
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* Rif > INH > PZA |
* Rif > INH > PZA |
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=== Adherence to Treatment === |
=== Adherence to Treatment === |
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* Refer to [http://www.letstalktb.org/ Let's Talk TB] |
* Refer to [http://www.letstalktb.org/ Let's Talk TB] |
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== Further Reading == |
== Further Reading == |
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* [https://www.canada.ca/en/public-health/services/infectious-diseases/canadian-tuberculosis-standards-7th-edition.htmlCanadian Tuberculosis Standards, 7th Edition (2014)] |
* [https://www.canada.ca/en/public-health/services/infectious-diseases/canadian-tuberculosis-standards-7th-edition.htmlCanadian Tuberculosis Standards, 7th Edition (2014)] |
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Revision as of 09:31, 10 November 2019
- Mycobacterium tuberculosis causes tuberculosis
- Most commonly pulmonary TB but extrapulmonary tuberculosis is possible (including adenitis, gastrointestinal TB, pericarditis, meningitis)
- Standard treatment for susceptible TB is RIPE x2mo then RI x4mo
Background
Microbiology
Epidemiology
- Reinfection accounts for ~40% of active tuberculosis in endemic countries
- Latent tuberculosis in ~30% of the global population
Clinical Presentation
Classification
- Primary vs. reactivation vs. reinfection
- Latent vs. active
Primary tuberculosis
- Primary tuberculosis is usually asymptomatic
- Possible presentations include mild URTI with cough and/or fever
- May be seen on CXR as infiltrate in mid-lung zones with hilar adenopathy
- Ghon complex, especially in children
- May progress in children and the immunocompromised patients
- Immunological phenomena
- Erythema nodosum
- Phlyctenular conjunctivitis
- Erythema induratum
Pulmonary tuberculosis
- Subacute or chronic cough (at least 2 to 3 weeks) eventually becoming productive and occasionally involving hemoptysis
- Should be suspected in any patient with cough and HIV infection
- Constitutional symptoms, with fevers, night sweats, and unexplained weight loss
- Usually from reactivation of latent tuberculosis infection, and usually reactivates in lung apices
- May transiently improve with partially-active antibiotics such as fluoroquinolones
Extra-pulmonary tuberculosis
- Pleural tuberculosis is most common extrapulmonary site
- Scrofula (cervical lymph node infection) next-most common
- Tuberculous meningitis
- Tuberculous pericarditis
- Renal tuberculosis
- Abdominal tuberculosis
- Gastrointestinal tuberculosis
Latent tuberculosis
- Refers to chronic latent infection contained within granulomas that may reactivate in the future
- Refer to Latent tuberculosis infection
Investigations
- Radiography: chest x-ray with or without CT chest
- Microbiology:
- Samples can include routine or induced sputum (x3) or bronchoscopy, or tissue sample
- Spontaneous sputum should include at least one morning sputum, ideally
- Acid-fast bacillus culture of sputum x3 is about 70% sensitive, and PCR (ANTB) x1 is about 75% sensitive
Management
- Standard HREZ x2mo then HR x4mo
- Isoniazid 5mg/kg/d, max 300mg daily
- Rifampin 10mg/kg/d
- Pyrazinamide 25mg/kg/d, max 2g daily
- Ethambutol 20mg/kg/d, max 1.2g daily
- Pyridoxine
- Airborne precautions until:
- Treated for at least 2 weeks
- 3x negative sputum smears
- Collected at 8- to 24-hour intervals, including one early morning collection
- Improvement in symptoms
IRIS
DILI
- Most common complication leading to treatment interruption, with a mortality of 6-12% if drugs are not stopped
- Rif > INH > PZA
- Most patients can have the same TB drugs reintroduced without recurrence of DILI, though recurrence can be delayed
- Procedure
- Hold if ALT >120 and symptoms, if ALT >200 even without symptoms, or bili >2x ULN
- Switch to second-line meds
- Reintroduce the original drugs once AST & ALT are <2x ULN
- Only rechallenge with pyrazinamide if it was a mild case
Adherence to Treatment
- Refer to Let's Talk TB
Further Reading
References
- ^ Daphne Yee, Chantal Valiquette, Marthe Pelletier, Isabelle Parisien, Isabelle Rocher, Dick Menzies. Incidence of Serious Side Effects from First-Line Antituberculosis Drugs among Patients Treated for Active Tuberculosis. American Journal of Respiratory and Critical Care Medicine. 2003;167(11):1472-1477. doi:10.1164/rccm.200206-626oc.
- ^ Jussi J. Saukkonen, David L. Cohn, Robert M. Jasmer, Steven Schenker, John A. Jereb, Charles M. Nolan, Charles A. Peloquin, Fred M. Gordin, David Nunes, Dorothy B. Strader, John Bernardo, Raman Venkataramanan, Timothy R. Sterling. An Official ATS Statement: Hepatotoxicity of Antituberculosis Therapy. American Journal of Respiratory and Critical Care Medicine. 2006;174(8):935-952. doi:10.1164/rccm.200510-1666st.
