Tuberculosis: Difference between revisions
Formatted the page. Corrected the references. |
Added links & information about latent and active infections |
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=== Disease === | === Disease === | ||
MTB is transmitted via droplet nuclei when a person coughs or sneezes and is then inhaled by another individual. The MTB travels to the alveoli where it comes into contact with [[Macrophage]]s that engulfs the MTB [[Pathogen|Pathog]][[Pathogen|en]]. MTB evades the immune system by binding to mannose receptors and is phagocytosed where it secretes a protein that modifies the [[Phagosome]] to prevent [[Phagosome]] - [[Lysosome]] fusion thus preventing [[Antigen]] presentation. The MTB then multiplies within the [[Macrophage]] until it bursts. However, some MTB [[Antigen]] s are still presented which activate [[T-cells]] which then activate [[Cytokines]] including IFN. IFN causes activation of macrophages which can now destroy the MTB. This is a cell-mediated response and helps to control the infection but MTB can still multiply in inactivated macrophages and eventually spreads to the [[Bronchi]] where it can spread to the rest of the body - extrapulmonary tuberculosis <ref>https://www.tbfacts.org/tb/</ref><ref>https://www.cdc.gov/tb/education/corecurr/pdf/chapter2.pdf</ref><ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC164219/</ref>. | MTB is transmitted via droplet nuclei when a person coughs or sneezes and is then inhaled by another individual. The MTB travels to the [[Alveoli|alveoli]] where it comes into contact with [[Macrophage]]s that engulfs the MTB [[Pathogen|Pathog]][[Pathogen|en]]. MTB evades the immune system by binding to mannose receptors and is phagocytosed where it secretes a protein that modifies the [[Phagosome]] to prevent [[Phagosome]] - [[Lysosome]] fusion thus preventing [[Antigen]] presentation. The MTB then multiplies within the [[Macrophage]] until it bursts. However, some MTB [[Antigen]] s are still presented which activate [[T-cells]] which then activate [[Cytokines]] including IFN. IFN causes activation of macrophages which can now destroy the MTB. This is a cell-mediated response and helps to control the infection but MTB can still multiply in inactivated macrophages and eventually spreads to the [[Bronchi]] where it can spread to the rest of the body - extrapulmonary tuberculosis <ref>https://www.tbfacts.org/tb/</ref><ref>https://www.cdc.gov/tb/education/corecurr/pdf/chapter2.pdf</ref><ref>https://www.ncbi.nlm.nih.gov/pmc/articles/PMC164219/</ref>. | ||
TB is considered to be either 'Latent' or 'Active'. A patient with a latent TB infection will not experience any of the usual symptoms that are characteristic of tuberculosis and is unable to spread the infection to others. <ref>https://www.cdc.gov/tb/publications/factsheets/general/ltbiandactivetb.htm</ref> According to the World Health Organisation, "the overall lifetime risk of developing active TB is about 10%" for a patient with a latent infection who is otherwise in a good state of general health. This risk of the infection becoming active increases in those with comprimised immune systems, such as [[HIV|HIV]] patients and the elderly. <ref>http://www.who.int/tb/areas-of-work/preventive-care/ltbi_faqs/en/</ref> If TB becomes active then the infected patient will be symptomatic and contagious and must be treated. | |||
=== At Risk: === | === At Risk: === | ||
*HIV | *[[HIV|HIV ]] | ||
*Diabetes | *[[Diabetes|Diabetes]] | ||
*Immunocompromised | *Immunocompromised | ||
* | *Smokers<br> | ||
*Elderly | |||
=== Symptoms === | === Symptoms === | ||
| Line 16: | Line 19: | ||
<u></u>Symptoms include: | <u></u>Symptoms include: | ||
* | *Cough | ||
* | *Night sweats | ||
* | *Appetite loss | ||
* | *Fever | ||
* | *Fatigue | ||
* | *Swollen neck<br> | ||
=== Prevention === | === Prevention === | ||
| Line 27: | Line 30: | ||
*<u></u>Good personal hygiene | *<u></u>Good personal hygiene | ||
*Cover mouth and nose when coughing/sneezing | *Cover mouth and nose when coughing/sneezing | ||
*Vaccination: BCG<br> | *Vaccination: [[Bacillus Calmette-Guérin (BCG)|BCG]]<br> | ||
*Screening and early diagnosis | |||
=== Treatment: === | === Treatment: === | ||
Revision as of 22:23, 23 October 2017
Tuberculosis (TB) is a bacterial infection that is caused by the bacteria Mycobacterium tuberculosis
Disease
MTB is transmitted via droplet nuclei when a person coughs or sneezes and is then inhaled by another individual. The MTB travels to the alveoli where it comes into contact with Macrophages that engulfs the MTB Pathogen. MTB evades the immune system by binding to mannose receptors and is phagocytosed where it secretes a protein that modifies the Phagosome to prevent Phagosome - Lysosome fusion thus preventing Antigen presentation. The MTB then multiplies within the Macrophage until it bursts. However, some MTB Antigen s are still presented which activate T-cells which then activate Cytokines including IFN. IFN causes activation of macrophages which can now destroy the MTB. This is a cell-mediated response and helps to control the infection but MTB can still multiply in inactivated macrophages and eventually spreads to the Bronchi where it can spread to the rest of the body - extrapulmonary tuberculosis [1][2][3].
TB is considered to be either 'Latent' or 'Active'. A patient with a latent TB infection will not experience any of the usual symptoms that are characteristic of tuberculosis and is unable to spread the infection to others. [4] According to the World Health Organisation, "the overall lifetime risk of developing active TB is about 10%" for a patient with a latent infection who is otherwise in a good state of general health. This risk of the infection becoming active increases in those with comprimised immune systems, such as HIV patients and the elderly. [5] If TB becomes active then the infected patient will be symptomatic and contagious and must be treated.
At Risk:
Symptoms
Symptoms include:
- Cough
- Night sweats
- Appetite loss
- Fever
- Fatigue
- Swollen neck
Prevention
- Good personal hygiene
- Cover mouth and nose when coughing/sneezing
- Vaccination: BCG
- Screening and early diagnosis
Treatment:
Two main antibiotics:
- Isoniazid - synthesis of essential mycolic acids by inhibiting NADH-dependent enoyl-ACP reductase (can cause nerve damage (peripheral neuropathy) so patients are given supplements of vitamin B6
- Rifampicin – affects transcription - β-subunit of RNA polymerase, where it binds and inhibits the elongation of messenger RNA. (side effect: reduced effectiveness of combined contraceptive pill)