Pathology of Lower GI Flashcards
What is inflammatory diarrhea
Diarrhea containing red/white cells and debris (maybe mucus)
Requires microscopic examination
Associated with inflammation of the colorectum
3 causes of colitis
Infection
Inflammatory bowel disease
Ischemic colitis
Indeterminate type inflammatory bowel disease
When its not possible to differentiate between Crohn’s and Ulcerative Colitis
Crohn’s Disease
Any part of the GI tract
Patchy distribution
Transmural inflammation with associated serositis (can get stenosis or fistular tracts)
Granulomas (chronic inflammation, so can see the presence of epitheliod macrophages arranged in a group, ringed by lymphocytes)
Ulcerative colitis
Colon only (starts in rectum and then moves proximal)
Continuous involvement
Inflammation limited to the mucosa
No granulomas
4 complications associated with Crohn’s
Fistula tracts
Stenosis and obstruction (can get cobblestone appearance)
Dysplasia and carcinoma
Extraintestinal features (arthritis, eye lesions, skin lesions)
3 complications with ulcerative colitis
Toxic megacolon (rare) Dysplasia and carcinoma Extraintestinal features (arthritis, eye lesions, skin lesions)
2 histological changes in ulcerative colitis
Absence of goblet cells
Crypt distortion and abscess
Microscopic colitis
When the colonoscopy is normal but the mucosal biopsy is abnormal
2 types: lymphocytic and collagenous
Present with chronic, watery, non-bloody diarrhea
More common in women
Diverticular disease of the colon
Presence of multiple diverticula
Usually on the left side of the colon that may be associated with clinical findings
From high intraluminal pressure
Risk factors include low-fiber diet, inactivity, obesity, muscle wall weakness
What are diverticula
Out pouchings of the wall of a hollow organ
Contain all layers of the wayy
What are pseudodiverticula? Where are they found?
Colon diverticula are pseudodiverticula because they do not contain all layers of the bowel wall
Not rectum, found in distal colon
3 complications of diverticulosis
Diverticulitis (erosion of the wall, may be associated with abscess, obstruction, perforation)
Bleeding
Diverticular disease associated colitis
Colorectal polyps
A polyp is an abnormal growth of tissue projecting from a mucus membrane
Can be found in the colon or rectum
Can be neoplastic or non-neoplastic (not pre-malignant)
Sessile vs pedunculated polyps
Sessile: broad base (plateau)
Pedunculated: has a stalk
Hamartoma
Collection of tissue in an organ that is normally found in that organ, but in an excessive amount
Increase in epithelium, CT and smooth muscle
Colorectal adenoma (what is it, 4 types)
Epithelial neoplasm that has the potential to progress to carcinoma
Pre-malignant neoplasm
Can be tubular, villous, tubulovillous, or serrated
What adenomas are at highest risk to progress to carcinoma? (4 things)
Size > 1 cm
Presence of high grade dysplasia
Villous architecture
Serrated polyp
In the colorectum only, when does invasive carcinoma begin?
When the cancer invades into the submucosa (through the muscularis mucosae)
The majority of colorectal carcinomas are what type of cancer?
Adenocarcinoma
Pathogenesis of acute appendicitis
Lumenal obstruction Bacterial overgrowth Inflammation/swelling (increased pressure) Localized ischemia Perforation Peritonitis or abscess formation
What is the most common neoplasm of appendix
Neuroendocrine tumor (carcinoid tumor)
Produces serotonin
Relatively benign, but may metastasize
Carcinoid syndrome
Flushing, diarrhea, and wheezing
May occur in carcinoid tumor metastasis to the liver
Serotonin released into the systemic circulation
How do people with microscopic colitis usually present?
Present with chronic, watery, non-bloody diarrhea
What does a neuroendocrine tumor of the appendix (carcinoid tumor) secrete?
Serotonin
