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Pathology Unit IV
Gastrointestinal Tract: Small/Large Intestine
66
Pathology
Graduate
03/06/2013

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Term
Pathogenesis of Cholera
Definition
organism produces an enterotoxin that causes massive secretion of water and sodium in small intestine and interferes with the ability of the large intestine to absorb water.
Term
general features of Cholera
Definition
Clinically the patient has profuse watery diarrhea. As a result they experience acute dehydration, hypovolemic shock, and metabolic acidosis.
Term
pathogensis of salmonella
Definition
Organism tends to involve Peyer patches (diffuse lymphatic nodules located in the terminal ileum). Bacteria invade mucosal surface and elaborate a toxin which causes diarrhea.
Term
general features of salmonella
Definition
: bloody diarrhea (more frequently involves large bowel) - often caused by salmonella-shigella organisms - "bacillary dysentery." Surface mucosa ulcerated and hemorrhagic
Term
pathogensis of tuberculosis of the bowel
Definition
can affect the terminal ileum (organism prefers Peyer's patches). Can result in peritoneal adhesions, perforation.
Term
general features of tuberculosis of the bowel
Definition
Pain, weight loss, night sweats, obstruction, GI bleeding
Term
pathogenesis of Giardiasis
Definition
flagellated protozoan that prefers the small intestine. Elaborates local irritant that produces diarrhea.
Term
general features of Giardiasis
Definition
Malabsorptive diarrhea from mucosal injury, Small intestinal biopsy may be normal or show blunting of villi with mixed inflammatory infiltrate
Term
pathogenesis of Strongyloidiasis
Definition
Infective filariform larvae penetrate skin or buccal mucosa, enter vessels, and reach the lungs, where they undergo some maturation. They pass into the alveoli, travel through the bronchi and trachea, and then enter the gastrointestinal tract (are coughed up and swallowed). The female worm deposits eggs in the crypts of the small intestine. The eggs hatch, producing rhabditiform larvae which are passed in the stool or can transform to filariform larvae in the colon; can penetrate the colonic mucosa, and cause reinfection.
Term
general features of Strongyloidiasis
Definition
important infection in immunosuppressed. Infection is by soil contaminated with fecal material.
Term
pathogenesis of Cryptosporidiosis
Definition
extracellular parasite transmitted by fecal-oral route
Term
general features of Cryptosporidiosis
Definition
Profuse diarrhea and malabsortion that may be life-threatening in immunosuppressed patients
Term
pathogenesis of Schistosomiasis
Definition
Cercariae can penetrate human skin coming into contact with the infected water. Larvae will penetrate the venules or lymphatics of the dermis, are carried through the bloodstream. Important lesions that develop are caused by the deposition of eggs in the liver, the walls of the bowel and urinary bladder, as well as other tissues.
Term
general features of Schistosomiasis
Definition
snail as intermediate host
Term
pathogenesis of Entamoebiasis
Definition
Invades surface of large intestine, causing ulcers. May penetrate vessels, travel to the liver, producing amebic abscesses.
Term
general features of Entamoebiasis
Definition
protozoan that primarily affects the colon
Term
pathogenesis of pseudomembranous colitis
Definition
The normally minor Commensal organisms of the bowel, classically Clostridium difficile, are able to proliferate and produce a necrotizing enterotoxin that causes an ulcerative inflammation on the surface of the bowel
Term
general features of pseudomembranous colitis
Definition
related to administration of broad-spectrum antibiotics
Term
Crohn Disease Definition
Definition
regional enteritis that affects terminal ileum or colon
Term
morphology of Crohn Disease
Definition
skip lesions, transmural inflammation, noncaseating granulomas, fissures with fistulas and anal involvement
Term
clinical course of Crohn Disease
Definition
extraitestional complications (arthritis, uveitis), variable and unpredictable presentation, diarrhea, crampy pain and fever, risk of carcinoma is less than with ulcerative colitis
Term
Ulcerative colitis definition
Definition
- recurrent acute and chronic ulceroinflammatory disorder affecting principally rectum and left colon, but sometimes the entire large bowel.
Term
morphology of Ulcerative colitis
Definition
nongranulomatous, continuous involvement (no skip lesions), psudopolyps, little fibrosis
Term
clinical course of Ulcerative colitis
Definition
arthritis, greater risk for carcinoma
Term
similarities between Crohn disease and Ulcerative colitis
Definition
accompanied by extraitestional complications, like arthritis, both peak incidence at 20-30
Term
differences between Crohn disease and Ulcerative colitis
Definition
Crohn is less prevalent, Crohn has a decreased risk of carcinoma, and Crohn has skip lesions, ulcerative colitis has continuous involvement, Crohn has noncaseating granulomas, ulcerative colitis is nongranulomatous, ulcerative colitis is limited to the colon, and Crohn can involve any part of the GI tract
Term
incidence of diverticular
disease
Definition
: rare in persons younger than 30, prevalence approaches 50% in western adult population after age 60, less common in Japan
Term
etiology of diverticular
disease
Definition
low fiber diet, straining at stool with back pressure, increased luminal pressure, exaggerated peristaltic contractions, spasmodic sequestration of bowel segments, reduce stool bulk
Term
pathogenesis of diverticular
disease
Definition
numerous outpunching of the colon, particularly in the rectosigmoid area (outpunching occur between the teniae coli). Developed after conditions of elevated luminal pressure in the sigmoid colon, muscle layer is discontinuous
Term
clinical course of diverticular
disease
Definition
asymptomatic, intermittent cramping, continuous lower abdominal discomfort, constipation and diarrhea. When complicated by fecoliths and inflammation - diverticulitis. "Left sided appendicitis.", perforation, abscess and bleeding
Term
diverticulosis definition
Definition
condition in which acquired diverticular outpouchings occur on the colonic mucosa and submucosa
Term
diverticulitis definition
Definition
inflammation of the diverticula
Term
hemorrhoids definition
Definition
dilated anal and perianal collateral vessels that connect the portal and caval venous systems to relieve elevated venous pressure within the hemorrhoid plexus
Term
formation of hemorrhoids
Definition
: related to low fiber, low residue diet, elevated venous pressure. With dehydration of fecal material in the large intestine a hard stool is formed, making straining at time of defecation necessary. The increased abdominal pressure forces hemorrhoidal veins to become dilated
Term
clinical significance of hemorrhoids
Definition
Hemorrhoids are also frequently related to pregnancy, especially at the time of delivery
Term
causes of bowel obstruction
Definition
may be related to some previous abdominal injury such as inflammation, surgery, endometriosis, conditions which all result in formation of adhesions (fibrous scars which contract). Other causes - hernia, intussusception, and volvulus. Constipation and invasion by tumor can also cause obstruction (these affect the large bowel more frequently).
Term
significance of bowel obstruction
Definition
painful and life threatening
Term
general incidence of tumors of small intestine
Definition
carcinoma (90-95%), lymphoma (4%), carcinoid (3%) and GIST (2%)
Term
the most common benign tumors of the small intestine
Definition
Leiomyoma
Term
the most common malignant tumors of the small intestine
Definition
Adenocarcinoma
Term
most common site of development of adenocarcinoma of the small intestine
Definition
tend to arise around ampulla of Vater (where pancreatic and bile ducts empty into duodenum).
Term
clinical symptoms of adenocarcinoma of the small intestine
Definition
Presenting signs - jaundice, pancreatitis - due to blockage of ampulla
Term
carcinoid tumor definition
Definition
neuroendocrine tumor
Term
common sites involved by carcinoid tumor
Definition
Appendix most common site of gut carcinoid; then ileum, stomach and colon
Term
clinical course of carcinoid tumor
Definition
Once tumor has metastasized to the liver, detoxification is not possible before the serotonin escapes into the circulation and causes the characteristic syndrome of episodic flushing of the skin, intestinal hypermotility (diarrhea, vomiting), bronchoconstrictive attacks resembling asthma, heart failure, edema.
Term
Colon Polyp definition
Definition
rare, can be non-neoplastic growth or neoplastic (adenoma)
Term
incidence of hyperplastic polyps of the colon
Definition
80-85% of gastric polyps
Term
gross features of hyperplastic polyps of the colon
Definition
left colon, less than 5mm in diameter, smooth, nodular protrusions of the mucosa, on the crests of musical folds, occur singly or in multiples (sigmoid colon and rectum), mature globet cells, absorptive cells, delayed shedding leads to crowding --> serrated surface architecture (hallmark)
Term
clinical significance of hyperplastic polyps of the colon
Definition
must be distinguished from sessile serrated adenomas, no malignant potential
Term
incidence of adenomatous polyps of the colon
Definition
most common neoplastic polyp
Term
gross features of adenomatous polyps of the colon
Definition
presence of epithelial dysplasia, 0.3-10 cm in diameters, pedunculated or sessile, nuclear hypochromasia, elongation, and stratification
Term
clinical significance of adenomatous polyps of the colon
Definition
give rise to a majority of colorectal adenocarcinomas
Term
relationship of adenomatous polyps of the colon to carcinoma
Definition
The extent of the neoplasm is the most important prognostic factor in patients with colon carcinoma. Most neoplasms are histologically well-differentiated. The larger the adenomatous growth and the more villous (finger-like) the growth pattern, the greater the chance it has carcinoma in it
Term
relationship of familial polyposis to carcinoma of the colon
Definition
100% risk of developing colon carcinoma
Term
incidence of colon carcinoma
Definition
common, 102,480 new cases in 2013 colon
Term
etiology of colon carcinoma
Definition
low fiber, high carbohydrate, high fat, decreased Vitamins A,C,E, Iron deficiency anemia in elderly highly worrisome for colorectal carcinoma
Term
pathogenesis of colon carcinoma
Definition
Carcinoma develops from adenomas through series of mutations leading ultimately to malignant transformation
Term
clinical course of colon carcinoma
Definition
Symptoms develop insidiously: bleeding, change in stool, pain, weakness, fatigue
Term
Difference in gross morphology between carcinoma of the left colon and carcinoma of the right colon
Definition
Left sided morphology is annular/endophytic with napkin ring constriction, right sided morphology is polypoid exophytic
Term
difference in symptoms between carcinoma of the left colon and carcinoma of the right colon
Definition
symptoms of left sided carcinoma bleeding, change in stool and pain or discomfort, symptoms of right sided carcinoma fatigue, weakness and IDA
Term
After a summertime camping trip in the Cascade mountains of Washington state, a 29-year-old man developed a mild watery diarrhea for a week. While on the trip he drank water from the mountain streams. A physical examination showed no abdominal pain or masses. He didn't have a fever. Bowel sounds were present. His stool was negative for occult blood. The diarrhea abated after 3 weeks. His two children are similarly affected by the organism shown in the image. What is this organism?
Definition
G. Lamblia
Term
Which organism is a flagellated protozoan that causes diarrhea and usually infects man as a contaminant of drinking water?
Definition
G. Lamblia
Term
This inflammatory bowel disease (IBD) is characterized by granulomatous inflammation involving all layers of the bowel wall. What is this IBD?
Definition
Crohns
Term
Which term includes all the others?
Definition
inflammatory bowel disease
Term
In which part of the gastrointestinal tract are neoplastic polyps MOST commonly seen?
Definition
Colon
Term
A 20-year-old man was healthy but has a family history of colon cancer at a young age. There were no abnormal physical exam findings. He underwent a colonoscopy and similar to the image shown, there were over 200 tubular adenomas ranging in size from 0.2 to 1 cm on gross inspection and microscopic examination of biopsies. Which of the following genetic diseases is he most likely to have?
Definition
Hereditary non-polyposis colon carcinoma syndrome
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