Cholangitis pathophysiology: Difference between revisions

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{{Cholangitis}}
{{Cholangitis}}
==Overview==
== Pathophysiology ==
== Pathophysiology ==
The presence of [[gallstones]] alone predisposes to bacterial colonization. 70% of patients with gallstones will have bacteria in the bile while normal bile is usually sterile. CBD have a higher probability of infection.  80% of stones can be culture positive.
===Pathogenesis===
[[Bile]], produced by the [[liver]], serves to eliminate cholesterol and [[bilirubin]] from the body, as well as emulsifying of fats to make them more soluble in water and aid in their digestion. It is formed in the liver by [[hepatocytes]] (liver cells) and excreted into the [[common hepatic duct]]. Part of the bile is stored in the [[gallbladder]] because of back pressure, and can be released at time of digestion. All bile reaches the [[duodenum]] through the common bile duct and the [[ampulla of Vater]].<ref name="wiki1"> Cholangitis. Wikipedia (2016).https://en.wikipedia.org/wiki/Ascending_cholangitis#Pathogenesis Accessed on April 1, 2016</ref>
 
The biliary tree is normally relatively free of bacteria because of certain protective mechanisms. The [[sphincter of Oddi]] acts as a mechanical barrier. The biliary system normally has low pressure and allows bile to flow freely through. This flushes bacteria, if present, into the duodenum, and does not allow establishment of an infection.<ref name="wiki1"> Cholangitis. Wikipedia (2016).https://en.wikipedia.org/wiki/Ascending_cholangitis#Pathogenesis Accessed on April 1, 2016</ref>  


The source of biliary infection is usually ascending from the [[duodenum]] or [[jejunum]] and less commonly direct hematogenous seeding of the [[Portal venous system|portal system]]. In the presence of obstruction, the small [[bowel]] becomes colonized with colonic flora.  The common organisms are [[E.coli]], [[Klebsiella]], [[Enterococcus]], [[Enterobacter]], [[Proteus]]. [[Anaerobic organism|Anaerobes]] ([[Strep]], [[Bacteroides]], [[Clostridia]]) can be found particularly in the elderly. Higher incidence of [[Pseudomonas]] in those who have been instrumented. Broad spectrum antibiotics to cover [[Gram-negative bacteria|Gram negatives]] including [[Pseudomonas]], Enterococcus  and anaerobes are needed up front. [[Cephalosporins]] should not be used as [[monotherapy]]. [[Ciprofloxacin]] has been shown in one study to be as effective as monotherapy despite poor coverage for anaerobes and EC.
Bacterial contamination alone in absence of obstruction does not usually result in cholangitis. However, increased pressure within the biliary system resulting from obstruction in the bile duct widens spaces between the cells lining the duct, bringing bacterially contaminated bile in contact with the blood stream. Increased biliary pressure decreases production of IgA immunoglobulins in the bile. This results in bacteremia (bacteria in the blood stream) and gives rise to the systemic inflammatory response syndrome (SIRS) comprising fever (often with rigors), tachycardia, increased respiratory rate and increased white blood cell count.<ref name="wiki1"> Cholangitis. Wikipedia (2016).https://en.wikipedia.org/wiki/Ascending_cholangitis#Pathogenesis Accessed on April 1, 2016</ref>  


The most common causes of biliary obstruction are [[Gallstone|biliary calculi]], benign stricture or malignant [[neoplasms]]. Benign strictures are caused by primary [[Sclerotherapy|sclerosing]] cholangitis, [[ischemic]] cholangitis, [[iatrogenic]] [[biliary tract]] injury, [[congenital disease]] and [[infection]].  Chronic inflammation predisposed to the development of cholangiocarcinomaExtraluminal obstruction can occur from [[pancreatic cancer]] or [[pseudocyst]], [[lymphoma]], [[hepatoma]], [[metastatic]] disease or ampullary cancer.
In ascending cholangitis, it is assumed that organisms migrate backwards up the bile duct as a result of partial obstruction and decreased function of the sphincter of Oddi.<ref name="wiki1"> Cholangitis. Wikipedia (2016).https://en.wikipedia.org/wiki/Ascending_cholangitis#Pathogenesis Accessed on April 1, 2016</ref>  


Biliary obstruction leads to elevated biliary pressures, favoring migration of bacteria into the portal circulation and bile.  As pressures increase [[hepatocyte]] secretion is impaired and bacteria move into the [[lymphatics]] and [[systemic circulation]].
The onset involves two factors:<ref name="pmid17252293">{{cite journal |vauthors=Kimura Y, Takada T, Kawarada Y, Nimura Y, Hirata K, Sekimoto M, Yoshida M, Mayumi T, Wada K, Miura F, Yasuda H, Yamashita Y, Nagino M, Hirota M, Tanaka A, Tsuyuguchi T, Strasberg SM, Gadacz TR |title=Definitions, pathophysiology, and epidemiology of acute cholangitis and cholecystitis: Tokyo Guidelines |journal=J Hepatobiliary Pancreat Surg |volume=14 |issue=1 |pages=15–26 |year=2007 |pmid=17252293 |pmc=2784509 |doi=10.1007/s00534-006-1152-y |url=}}</ref>
* Increased bacteria in the bile duct
*Elevated intraductal pressure in the bile duct that allows translocation of bacteria or [[endotoxins]] into the [[vascular system]].
In acute cholangitis, with the elevated intraductal biliary pressure, the bile ductules tend to become more permeable to the translocation of bacteria and toxins. This process results in serious infections that can be fatal, such as hepatic abscess and [[sepsis]].<ref name="pmid17252293">{{cite journal |vauthors=Kimura Y, Takada T, Kawarada Y, Nimura Y, Hirata K, Sekimoto M, Yoshida M, Mayumi T, Wada K, Miura F, Yasuda H, Yamashita Y, Nagino M, Hirota M, Tanaka A, Tsuyuguchi T, Strasberg SM, Gadacz TR |title=Definitions, pathophysiology, and epidemiology of acute cholangitis and cholecystitis: Tokyo Guidelines |journal=J Hepatobiliary Pancreat Surg |volume=14 |issue=1 |pages=15–26 |year=2007 |pmid=17252293 |pmc=2784509 |doi=10.1007/s00534-006-1152-y |url=}}</ref>


==References==
==References==

Revision as of 18:36, 1 April 2016

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Farwa Haideri [2]

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Overview

Pathophysiology

Pathogenesis

Bile, produced by the liver, serves to eliminate cholesterol and bilirubin from the body, as well as emulsifying of fats to make them more soluble in water and aid in their digestion. It is formed in the liver by hepatocytes (liver cells) and excreted into the common hepatic duct. Part of the bile is stored in the gallbladder because of back pressure, and can be released at time of digestion. All bile reaches the duodenum through the common bile duct and the ampulla of Vater.[1]

The biliary tree is normally relatively free of bacteria because of certain protective mechanisms. The sphincter of Oddi acts as a mechanical barrier. The biliary system normally has low pressure and allows bile to flow freely through. This flushes bacteria, if present, into the duodenum, and does not allow establishment of an infection.[1]

Bacterial contamination alone in absence of obstruction does not usually result in cholangitis. However, increased pressure within the biliary system resulting from obstruction in the bile duct widens spaces between the cells lining the duct, bringing bacterially contaminated bile in contact with the blood stream. Increased biliary pressure decreases production of IgA immunoglobulins in the bile. This results in bacteremia (bacteria in the blood stream) and gives rise to the systemic inflammatory response syndrome (SIRS) comprising fever (often with rigors), tachycardia, increased respiratory rate and increased white blood cell count.[1]

In ascending cholangitis, it is assumed that organisms migrate backwards up the bile duct as a result of partial obstruction and decreased function of the sphincter of Oddi.[1]

The onset involves two factors:[2]

  • Increased bacteria in the bile duct
  • Elevated intraductal pressure in the bile duct that allows translocation of bacteria or endotoxins into the vascular system.

In acute cholangitis, with the elevated intraductal biliary pressure, the bile ductules tend to become more permeable to the translocation of bacteria and toxins. This process results in serious infections that can be fatal, such as hepatic abscess and sepsis.[2]

References

  1. 1.0 1.1 1.2 1.3 Cholangitis. Wikipedia (2016).https://en.wikipedia.org/wiki/Ascending_cholangitis#Pathogenesis Accessed on April 1, 2016
  2. 2.0 2.1 Kimura Y, Takada T, Kawarada Y, Nimura Y, Hirata K, Sekimoto M, Yoshida M, Mayumi T, Wada K, Miura F, Yasuda H, Yamashita Y, Nagino M, Hirota M, Tanaka A, Tsuyuguchi T, Strasberg SM, Gadacz TR (2007). "Definitions, pathophysiology, and epidemiology of acute cholangitis and cholecystitis: Tokyo Guidelines". J Hepatobiliary Pancreat Surg. 14 (1): 15–26. doi:10.1007/s00534-006-1152-y. PMC 2784509. PMID 17252293.


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