Amoebiasis pathophysiology: Difference between revisions
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__NOTOC__ | __NOTOC__ | ||
{{Amoebiasis}} | {{Amoebiasis}} | ||
{{CMG}}; {{AE}} {{ | {{CMG}}; {{AE}} {{YD}}; {{SSK}} | ||
==Overview== | ==Overview== | ||
==Pathophysiology== | |||
===Transmission=== | |||
==Transmission== | |||
*''E. histolytica'' cyst is usually transmitted by the fecal-oral route through contaminated drinking water or food) | *''E. histolytica'' cyst is usually transmitted by the fecal-oral route through contaminated drinking water or food) | ||
*''E. histolytica'' cyst may also be transmitted indirectly through direct contact with infected individuals. | *''E. histolytica'' cyst may also be transmitted indirectly through direct contact with infected individuals. | ||
===Pathogenesis=== | |||
*Following transmission, ''E. histolytica'' trophozoites inhabit in the large intestine of the human host. | |||
*In the large intestine, the trophozoite invades the intestinal mucosa into the blood stream. Simultaneously, they form resistant cysts that are then excreted in human stools. | |||
*Once in the bloodstream, the trophozoite migrates into the portal circulation and develops amebic liver abscess. | |||
====Invasion of Intestinal Mucosa==== | |||
*''E. histolytica'' trophozoites secrete proteases, which induce the release of mucin from goblet cells, resulting in glandular hyperplasia. | |||
*''E. histolytica'' is | |||
===Gross Pathology=== | |||
On gross pathology, the following findings may be present in patients with amebiasis: | |||
*Wavy surface epithelium (results from focal release of mucin and spasm of the muscular layer) | |||
*Nodular and/or irregular ulcers in the cecum (most common), sigmoid colon, and rectum. Early ulcers are usually in the interglandular epithelium. | |||
:*Nodular: small (sub-centrimetric), rounded, elevated lesions with necrotic center and edematous rim | |||
:*Irregular: large (1-5 cm), shallow with broad elevated margins | |||
Note: the mucosal folds may occasionally hide small colonic ulcers (false-negative results) | |||
===Microscopic Pathology=== | |||
*On microscopic pathology, amebiasis is characterized by a flask ulcer (deep, microhemorrhagic ulceration involving the submucosa), which is a characteristic of advanced disease. | |||
*Additional findings may be present in patients with amebiasis: | |||
:*Interglandular ulceration | |||
:*Hyperemia | |||
:*Thickened mucosa | |||
:*Reactive glandular hyperplasia | |||
:*Stromal edema | |||
:*Infiltration of neutrophils, eosinophils, and macrophages | |||
:*Lymphoid aggregates | |||
:*Detection of amebas on surface exudate | |||
:*Tissue necrosis, usually fibrinoid (advanced lesion) | |||
:*Formation of granulation tissue (advanced lesion) | |||
==Gallery== | ==Gallery== | ||
Revision as of 17:55, 10 March 2016
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Amoebiasis Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Amoebiasis pathophysiology On the Web |
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American Roentgen Ray Society Images of Amoebiasis pathophysiology |
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Risk calculators and risk factors for Amoebiasis pathophysiology |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Yazan Daaboul, M.D.; Serge Korjian M.D.
Overview
Pathophysiology
Transmission
- E. histolytica cyst is usually transmitted by the fecal-oral route through contaminated drinking water or food)
- E. histolytica cyst may also be transmitted indirectly through direct contact with infected individuals.
Pathogenesis
- Following transmission, E. histolytica trophozoites inhabit in the large intestine of the human host.
- In the large intestine, the trophozoite invades the intestinal mucosa into the blood stream. Simultaneously, they form resistant cysts that are then excreted in human stools.
- Once in the bloodstream, the trophozoite migrates into the portal circulation and develops amebic liver abscess.
Invasion of Intestinal Mucosa
- E. histolytica trophozoites secrete proteases, which induce the release of mucin from goblet cells, resulting in glandular hyperplasia.
- E. histolytica is
Gross Pathology
On gross pathology, the following findings may be present in patients with amebiasis:
- Wavy surface epithelium (results from focal release of mucin and spasm of the muscular layer)
- Nodular and/or irregular ulcers in the cecum (most common), sigmoid colon, and rectum. Early ulcers are usually in the interglandular epithelium.
- Nodular: small (sub-centrimetric), rounded, elevated lesions with necrotic center and edematous rim
- Irregular: large (1-5 cm), shallow with broad elevated margins
Note: the mucosal folds may occasionally hide small colonic ulcers (false-negative results)
Microscopic Pathology
- On microscopic pathology, amebiasis is characterized by a flask ulcer (deep, microhemorrhagic ulceration involving the submucosa), which is a characteristic of advanced disease.
- Additional findings may be present in patients with amebiasis:
- Interglandular ulceration
- Hyperemia
- Thickened mucosa
- Reactive glandular hyperplasia
- Stromal edema
- Infiltration of neutrophils, eosinophils, and macrophages
- Lymphoid aggregates
- Detection of amebas on surface exudate
- Tissue necrosis, usually fibrinoid (advanced lesion)
- Formation of granulation tissue (advanced lesion)
Gallery
-
![Invasive extraintestinal amebiasis. Adapted from Public Health Image Library (PHIL). [1]](/images/4/48/Amebiasis04.jpeg)
Invasive extraintestinal amebiasis. Adapted from Public Health Image Library (PHIL). [1]
-
![Amebic abscess of liver. Adapted from Public Health Image Library (PHIL). [1]](/images/e/ef/Amebiasis11.jpeg)
Amebic abscess of liver. Adapted from Public Health Image Library (PHIL). [1]
-
![Intestinal ulcers due to amebiasis. Adapted from Public Health Image Library (PHIL). [1]](/images/b/b0/Amebiasis12.jpeg)
Intestinal ulcers due to amebiasis. Adapted from Public Health Image Library (PHIL). [1]
-
![Intestinal ulcers due to amebiasis. Adapted from Public Health Image Library (PHIL). [1]](/images/b/b0/Amebiasis13.jpeg)
Intestinal ulcers due to amebiasis. Adapted from Public Health Image Library (PHIL). [1]
-
![Intestinal amebiasis. Adapted from Public Health Image Library (PHIL). [1]](/images/7/72/Amebiasis15.jpeg)
Intestinal amebiasis. Adapted from Public Health Image Library (PHIL). [1]
-
![Amebic abscess in liver. Adapted from Public Health Image Library (PHIL). [1]](/images/c/cf/Amebiasis16.jpeg)
Amebic abscess in liver. Adapted from Public Health Image Library (PHIL). [1]
-
![Amebic abscess in liver. Adapted from Public Health Image Library (PHIL). [1]](/images/b/b6/Amebiasis17.jpeg)
Amebic abscess in liver. Adapted from Public Health Image Library (PHIL). [1]
-
![Amebiasis in intestine. Adapted from Public Health Image Library (PHIL). [1]](/images/1/1c/Amebiasis18.jpeg)
Amebiasis in intestine. Adapted from Public Health Image Library (PHIL). [1]
![Invasive extraintestinal amebiasis. Adapted from Public Health Image Library (PHIL). [1]](/index.php/File:Amebiasis04.jpeg)
![Amebic abscess of liver. Adapted from Public Health Image Library (PHIL). [1]](/index.php/File:Amebiasis11.jpeg)
![Intestinal ulcers due to amebiasis. Adapted from Public Health Image Library (PHIL). [1]](/index.php/File:Amebiasis12.jpeg)
![Intestinal ulcers due to amebiasis. Adapted from Public Health Image Library (PHIL). [1]](/index.php/File:Amebiasis13.jpeg)
![Intestinal amebiasis. Adapted from Public Health Image Library (PHIL). [1]](/index.php/File:Amebiasis15.jpeg)
![Amebic abscess in liver. Adapted from Public Health Image Library (PHIL). [1]](/index.php/File:Amebiasis16.jpeg)
![Amebic abscess in liver. Adapted from Public Health Image Library (PHIL). [1]](/index.php/File:Amebiasis17.jpeg)
![Amebiasis in intestine. Adapted from Public Health Image Library (PHIL). [1]](/index.php/File:Amebiasis18.jpeg)