Bronchiectasis pathophysiology: Difference between revisions

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==Overview==
==Overview==
Bronchiectasis involves bronchi that are permanently dilated, inflamed, and easily collapsible. This results in airflow obstruction and impaired clearance of secretions.
Bronchiectasis involves bronchi that are permanently [[dilated]]  inflamed, and easily collapsible. This results in airflow obstruction and impaired clearance of [[secretions]] Cole's Cycle describes how infections and a defect in the host defense are factors for this disease. An immune response also plays a role in the pathogenesis, which involves [[neutrophils]], [[lymphocytes]], and [[macrophages]].
 
==Pathophysiology==
*Dilation of the bronchial walls results in airflow obstruction and impaired clearance of secretions because the dilated areas interrupt normal air pressure of the bronchial tubes, causing [[sputum]] to pool inside the dilated areas instead of being pushed upward.<ref>{{cite journal |author=Morrissey BM |title=Pathogenesis of bronchiectasis |language=English |journal=Clin Chest Med|volume=28 |issue=2 |pages=289-96 |year=2007 |pmid=17467548 |doi=}}</ref> 
*The pooled [[sputum]] provides an environment conducive to the growth of infectious [[pathogen|pathogens]]. Therefore, that particular area is vulnerable to infections. 
*The more infections that the lungs experience, the more damaged the [[alveoli]] in the lung become.
*With more damage to the lung tissue, the [[bronchial tube]]s become more inelastic and dilated. This creates a perpetual, destructive cycle within this disease.


==Pathophysiology<ref>{{cite journal |author=Morrissey BM |title=Pathogenesis of bronchiectasis |language=English |journal=Clin Chest Med|volume=28 |issue=2 |pages=289-96 |year=2007 |pmid=17467548 |doi=}}</ref>==
*[[Dilation]] of the [[bronchial]] walls results in airflow obstruction and impaired clearance of secretions
*The dilated areas interrupt normal air pressure of the [[bronchial]] tubes, causing [[sputum]] to pool inside the dilated areas instead of being pushed upward
*The pooled [[sputum]] provides an environment favorable to the growth of infectious [[pathogen|pathogens]] 
*The more [[infections]] that the lungs experience, the more damaged the [[alveoli]] in the lung become
*With more damage to the lung tissue, the [[bronchial tube]]s become more inelastic and dilated
*This creates a perpetual, destructive cycle 
*The biopsies indicate that the infiltrate contains [[neutrophils]], [[T lymphocytes]] and [[macrophages]]
*The sputum contains [[elastase]], [[interleukin-8]], tumor necrosis factor a  (TNF-a), and prostanoids


===Cole's Cycle<ref name="pmid20037680">{{cite journal| author=King PT| title=The pathophysiology of bronchiectasis. | journal=Int J Chron Obstruct Pulmon Dis | year= 2009 | volume= 4 | issue=  | pages= 411-9 | pmid=20037680 | doi= | pmc=PMC2793069 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20037680  }} </ref>===
===Cole's Cycle<ref name="pmid20037680">{{cite journal| author=King PT| title=The pathophysiology of bronchiectasis. | journal=Int J Chron Obstruct Pulmon Dis | year= 2009 | volume= 4 | issue=  | pages= 411-9 | pmid=20037680 | doi= | pmc=PMC2793069 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=20037680  }} </ref>===
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*The most widely known model of the development of bronchiectasis  
*The most widely known model of the development of bronchiectasis  
*Impaired muco-ciliary clearance due to genetic susceptibility causes environmental insult
*Impaired muco-ciliary clearance due to genetic susceptibility causes environmental insult
*Results in persistence of microbes in the sinobronchial tree and microbial colonization
*Results in persistence of microbes in the sinobronchial tree  
*The microbial infection causes chronic inflammation  
*The microbial infection causes chronic inflammation  
*This results in tissue damage and impaired mucociliary motility
*This results in tissue damage and impaired mucociliary motility
*This leads to more infection with a cycle of inflammation causing lung damage
*This leads to more infection with a cycle of inflammation causing lung damage
*Two factors required for the development of this condition are persistent infection and a defect in host defense
*Two factors required for the development of this condition are persistent infection and a defect in host defense
*The biopsies indicate that the infiltrate contains [[neutrophils]], [[T lymphocytes]] and [[macrophages]]. The sputum contains [[elastase]], [[interleukin-8]], tumor necrosis factor a  (TNF-a), and prostanoids.


===Immune Response===
===Immune Response===
Line 28: Line 30:
F1.large.jpg | Schematic representation of a vicious circle of events which occurs during chronic bronchial infection. IL: interleukin; TNF: tumour necrosis factor; LT: leukotriene; MMP: matrix metalloproteinase <br> [http://erj.ersjournals.com/content/31/2/396/F1.large.jpg <font size="-2">''European Respiratory Journal''</font>]
F1.large.jpg | Schematic representation of a vicious circle of events which occurs during chronic bronchial infection. IL: interleukin; TNF: tumour necrosis factor; LT: leukotriene; MMP: matrix metalloproteinase <br> [http://erj.ersjournals.com/content/31/2/396/F1.large.jpg <font size="-2">''European Respiratory Journal''</font>]
</gallery>
</gallery>
**The biopsies indicate that the infiltrate contains [[neutrophils]], [[T lymphocytes]] and [[macrophages]]. The sputum contains [[elastase]], [[interleukin-8]], tumor necrosis factor a  (TNF-a), and prostanoids
 


==References==
==References==

Revision as of 12:54, 29 June 2015

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Saarah T. Alkhairy, M.D.

Overview

Bronchiectasis involves bronchi that are permanently dilated inflamed, and easily collapsible. This results in airflow obstruction and impaired clearance of secretions Cole's Cycle describes how infections and a defect in the host defense are factors for this disease. An immune response also plays a role in the pathogenesis, which involves neutrophils, lymphocytes, and macrophages.

Pathophysiology[1]

  • Dilation of the bronchial walls results in airflow obstruction and impaired clearance of secretions
  • The dilated areas interrupt normal air pressure of the bronchial tubes, causing sputum to pool inside the dilated areas instead of being pushed upward
  • The pooled sputum provides an environment favorable to the growth of infectious pathogens
  • The more infections that the lungs experience, the more damaged the alveoli in the lung become
  • With more damage to the lung tissue, the bronchial tubes become more inelastic and dilated
  • This creates a perpetual, destructive cycle
  • The biopsies indicate that the infiltrate contains neutrophils, T lymphocytes and macrophages
  • The sputum contains elastase, interleukin-8, tumor necrosis factor a (TNF-a), and prostanoids

Cole's Cycle[2]

  • Also known as Cole's "vicious cycle hypothesis"
  • The most widely known model of the development of bronchiectasis
  • Impaired muco-ciliary clearance due to genetic susceptibility causes environmental insult
  • Results in persistence of microbes in the sinobronchial tree
  • The microbial infection causes chronic inflammation
  • This results in tissue damage and impaired mucociliary motility
  • This leads to more infection with a cycle of inflammation causing lung damage
  • Two factors required for the development of this condition are persistent infection and a defect in host defense

Immune Response


References

  1. Morrissey BM (2007). "Pathogenesis of bronchiectasis". Clin Chest Med. 28 (2): 289–96. PMID 17467548.
  2. King PT (2009). "The pathophysiology of bronchiectasis". Int J Chron Obstruct Pulmon Dis. 4: 411–9. PMC 2793069. PMID 20037680.


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