Infectious colitis pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Qasim Salau, M.B.B.S., FMCPaed [2]
Overview
Pathophysiology
Pathogenesis
Infectious colitis occurs following invasion of colonic mucosa or attachment to the colonic mucosa by a micro-organism causing inflammation
Pathogenesis of Infectious colitis
- Enteric organisms that cause colitis are usually transmitted through fecal-oral route especially in children. As few as 100 bacterial cells can be enough to cause an infection.[1]
- May also occur following antibiotic use, especially broad spectrum antibiotics.
- Can also be acquired as a sexually transmitted infection (STI) among individuals who practice unsafe anal sex especially among men who have sex with men (MSM)
- In MSM the pathogens are transmitted directly through overt or microabrasions in the rectal mucosa or indirectly during oral-anal contact.[2]
The pathogenesis, gross and microscopic pathology of infectious colitis will depend on the causative organism as follows:
- Shigella spp.
- Campylobacter jejuni
- Clostridium difficile
- Escherichia coli
- Nontyphoidal Salmonella
- Entameoba histolytica
- Chlamydia trachomatis
- Cytomegalovirus
- Yersinia enterocolitica
- Pseudomembranous colitis. The gross pathologic finding is presence of diffuse, small, 2 to 10mm, raised yellowish (or whitish) lesions. Mucosa in between lesions may appear normal. Lesions may merge giving rise to a characteristic "pseudomembrane" layer over the mucosa.
Microscopic pathology
- In pseudomembranous colitis microscopy shows[5]
- Heaped necrotic tissue
- Polymorphonuclear neutrophils in the lamina propria, breeching the epithelium like a "volcanic eruption".
- With or without capillary thrombi
- On microscopy, the characteristic finding in ulcerative colitis is presence of lymphocytes and plasma cells in the deeper aspect of the lamina propria (basal lymphoplasmacytosis).
- Crypt architecture is destroyed.
- Abscesses may also be seen in the crypts.
-
Pseudomembranous colitis. H& E staining showing pseudomembranes in Clostridium colitis [6]
References
- ↑ Levinson, Warren E (2006). Review of Medical Microbiology and Immunology (9 ed.). McGraw-Hill Medical Publishing Division. p. 30. ISBN 978-0-07-146031-6. Retrieved February 27, 2012.
- ↑ Template:Rompalo AM. Chapter 9: Proctitis and Proctocolitis. In Klausner JD, Hook III EW. CURRENT Diagnosis & Treatment of Sexually Transmitted Diseases. McGraw Hill Professional; 2007
- ↑ Libre Pathology. Pseudomembranous colitis. https://librepathology.org/wiki/Pseudomembranous_colitis Accessed on August 31, 2016
- ↑ Libre Pathology. Pseudomembranous colitis. https://librepathology.org Accessed on September 1, 2016
- ↑ Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 837-8. ISBN 0-7216-0187-1}}
- ↑ Libre Pathology. Pseudomembranous colitis. https://librepathology.org/wiki/File:Colonic_pseudomembranes_low_mag.jpg Accessed on September 1, 2016