Colon Flashcards
What percent of the lamina propria is inflammatory cells in normal colonic mucosa?
50%
T/F- water must cross the surface epithelium and collagen table to enter the capillaries of the superficial lamina propria
true
Hirschsprung disease is associated with what genetic abnormality?
Down syndrome
T/F- Although males get hirschsprung disease more frequently than females, females are more severely affected
true
A neonate presents with failure to pass meconium in the immediate postnatal period. What is most likely diagnosis?
Hirschsprung disease
Name 5 common causes of acute colitis
Bacterial viral (norovirus, rotavirus, adenovirus) Protozoal and parasitic Toxin Ischemic
Name 4 causes of chronic colitis
Ulcerative colitis, Crohn’s disease
Lyphocytic colitis, collagenous colitis
T/F- crypt architecture is not preserved in acute bacterial colitis
False, it is preserved
Name 2 examples of toxin damage causing colitis
- C. dificile (pseudomembranous colitis), most commonly after 3rd gen cephalosporin
- Enterohemorrhagic E. Coli (fecal contamination, raw hamburger, sprouts, apples picked in pasture)
What is the pseudomembrane composed of?
fibrin, mucin, neutrophils
ichemic colitis most often occurs in older patients with vascular disease and presents with abdominal pain, nausea, vomiting, bloody stools. Where are the watershed zones where this most often occurs?
splenic flexure, sigmoid colon, rectum
T/F- Irritable bowel syndrome will show gross and microscopic abnormalities
False, it will be normal
In chronic colitis, is crypt architecture and branching preserved or distorted?
distorted and irregular crypts are signs of chronicity
Compare ulcerative colitis and Crohns disease
- UC: diffuse, superficial (only mucosal layer affected), colon only
- Crohns: focal (lymphoid aggregates or granulomas), transmural (mucosa through to serosa), anywhere in the GI tract (especially ileum and colon)
If you see a terminal ileum with a thick wall, stricture, and linear ulcer what is it most likely?
Crohn’s disease
Does Crohn’s or ulcerative colitis carry a greater risk for cancer?
Ulcerative colitis
The term microscopic colitis encompasses what two diseases?
- Lymphocytic and collagenous colitis
- these will appear normal endoscopically
T/F- in collagenous colitis you will see microscopically normal crypt architecture, increased superficial chronic inflammation of the lamina propria, increased numbers of intraepithelial lymphocytes
False, that is lymphocytic colitis
What will you see histologically in collagenous colitis?
A thickened, irregular subepithelial collagen layer entrapping capillaries and cells
Is diverticulosis related to the western diet?
yes
Although only 20% of patients are symptomatic for diverticulosis, what will they present with?
cramping, lower abdominal discomfort, constipation/diarrhea, distention
Where is the weakest spot in the muscle that allows for diverticuli to form?
where
nerves and vessels
penetrate
Can diverticulitis perforate?
yes
T/F- Inflammatory polyps are often associated with IBD, but also seen with ischemic colitis, infectious colitis, necrotizing enterocolitis
true
Juvenile polyps often present with rectal bleeding or prolapse of polyp through the rectum. Does polyposis syndrome increase risk of malignancy?
risk of upper and lower GI malignancies
For Peutz-Jeghers syndrome, what is the mode of inheritance? Symptoms? Complications?
- Autosomal dominant
- Mucocutaneous pigmentation
- polyps of the upper and lower GI tract with increased risk of carcinoma, pancreatic, breast, and ovarian carcinomas
Hyperplastic polyps are commonly found where? Are they malignant or benign?
- Left colon and rectum
- Benign
Do sessile, serrated adenomas/polyps have malignant potential? Where are they commonly found?
yes, most often on right side of colon
How do you distinguish a sessile serrated adenoma from a hyper plastic polyp?
Sessile serrated adenoma has normal base, hyper plastic polyp has abnormal base
Name three different types of adenomas
- tubular
- tubulovillous
- villous
Are adenomas a precursor to colon cancer?
yes “These are the MAJOR precursor to colon cancer”
Once an adenoma passes ______ layer it becomes invasive
muscularis mucosae
T/F- adenocarcinoma is rare in western populations
False, VERY common in western populations and account for 3% of cancer deaths
Are adenocarcinomas related to dietary factors?
yes, low intake of vegetable fiber and high intake of refined carbohydrates and fat
Is the preclinical phase of colorectal cancer long or short?
long (10 years)
What lesion do the vast majority of colorectal cancers begin with?
tubular adenoma
T/F- The majority of colorectal adenocarcinomas are associated with familial syndromes such as FAP, HNPCC, juvenile polyposis coli
False, 90% are sporadic! FAP: 1% HNPCC: 5% Juvenile Polyposis coli: 1% IBD: 1%
Familial adenomatous polyposis is an autosomal dominant mutation in what gene?
APC (adenomatous polyposis coli) gene
How many adenomas would you find in a colon of a person with FAP?
at least 100, often more than 1000
T/F- colorectal adenocarcinoma will develop in 100% of untreated FAP patients
true
HNPCC includes lynch syndrome I and II, what is the difference?
-Lynch Syndrome I – confined to colorectum
-Lynch syndrome II – colorectal carcinoma associated with extra-colonic cancers
(Endometrium, stomach, small bowel, hepatobiliary tract, pancreas, ovary, urinary tract, brain (GBM), sebaceous neoplasms of the skin (Muir-Torre syndrome))
Is HNPCC autosomal dominant or recessive? What type of gene does this affect?
dominant
DNA mismatch repair gene (risk of colorectal cancer is 70% by age 70)
