Flashcards in GI: Small and Large Intestine II Deck (50)
What is the infectious disease agent responsible for pseudomembranous colitis?
C. diff (toxins A and B)
Which parasitic infection presents with bloody diarrhea?
What is the genetic abnormality in familial adenomatous polyposis (FAP)?
mutation of APC gene
What are the 2 varieties of GI protrusions?
What comprises a "true" diverticulum?
all three wall layers (ex: Meckel's)
If the diverticulum only penetrates the mucosa and submucosa, what is it called?
false or pseudo
many diverticuli, usually in sigmoid colon where vasa recta perforate colon
(most cases in elderly, associated with low fiber diets)
inflammation of diverticula (LLQ pain, fever, leukocytosis) can perforate causing peritonitis, abscesses, etc)
serosal lined out-pouching of peritoneum (loop of intestines are trapped within hernia sac)
bowel compressed and twisted at mouth of hernia
What are some causes of ischemic bowel disease?
anything that causes vasculature problems (atherosclerosis, aortic aneurysm, hypercoagulable states, etc)
What are some symptoms of ischemic bowel disease?
sudden/severe abdominal pain
bloody diarrhea, melanotic stools
What is the main watershed zone in the bowel?
splenic flexure (furthest from the blood supply - most vulnerable to ischemia)
What does ischemic bowel disease look like on histology?
necrotic mucosa next to intact crypts
Internal hemorrhoids are __________ the pectinate lines and are ____________
External hemorrhoids are _________ the pectinate line and are ____________
True or false: both varieties of hemorrhoids are worse with defecations
Name the 4 kinds of bowel growths that are NON-neoplastic
1) inflammatory polyp
2) juvenile polyp
3) hamatomaous (psutz-Jeghers syndrome)
4) hyperplastic polyp
What are inflammatory polyps and how do they form?
form in the colon due to impaired relaxation of the anorectal sphincter which creates a sharp angle at the anterior rectal shelf (leads to recurrent abrasion and ulceration of the overlying rectal mucosa)
How are inflammatory polyps associated with prolapse?
they are pulled by the fecal stream
What do inflammatory polyps look like on histology?
lamina propria fibromuscular hyperplasia, inflammation and erosion and epithelial hyperplasia
Where do juvenile polyps occur?
rectum in kids
Are juvenile polyps concerning?
not if single, if multiple there is an increased risk of adenocarcinoma
What is Hamatomatous (Peutz-Jeghers syndrome)?
formation of many hamartomas throughout GI tract (looks like hyperpigmented melanotic macules of mouth, lips, genitalia, hands)
polyps have no malignant potential
What are hyperplastic polyps?
look like adenomas, proliferation of mature goblet cells
What are adenomatous growths?
benign polyps that are precursors to majority of colorectal adenocarcinomas
(can be pedunculated, sessile, tubular, and villous)
What are the two major things to monitor in adenomatous growths so that they do not become cancerous?
size and presence of high grade dysplasia
Sessile serrated adenomas occur predominantly where?
Define adenomatous dysplasia
neoplastic dysplastic epithelium which lines the glands as tall hypercrhomatic somewhat disordered cells with or without mucin production
What is FAP?
an AD disease that leads to thousands of polyps and ALWAYS leads to colorectal adenocarcinoma
How do you treat FAP?
What causes FAP?
What are 3 neoplastic GI conditions?
2) sessile serrated adenoma
3) adenomatous dysplasia
What are the 2 variants of FAP?
1) gardner - osteomas of mandible
2) turcots - DNA repair mutations, get glioblastomas
What is HNPCC?
hereditary nonpolyposis colorectal cancer (fewer polyps but cancer still occurs at younger age)
What causes HNPCC?
mutation in DNA mismatch repair genes
What are the two molecular pathways that can lead to colorectal cancer
1) APC/WNT pathway
2) DNA mismatch repair
True or false: for the APC/WNT pathway, both copies must be functionally inactivated to cause cancer
What is APC?
a negative regulator of the beta catenin pathway
so without APC, beta catenin goes into the nucleus and activates transcription of genes such as those encoding MYC and cyclin D1
Which pathway is associated with increased beta catenin?
DNA mismatch repair leads to ________
What kind of adenomas are caused by HNPCC?
sporadic colorectal cancer is associated with _______ while sessile serrated adenoma is associated with ________
sporadic CRC --> FAP
SSA --> HNPCC
What doe colorectal cancer look like on barium xray
apple core (pushes on colon)
screen after 50
What is partially protective for CRC?
high fiber diet
What are some signs and symptoms of right sided CRC?
iron deficient anemia (surface ulceration and blood loss)
ulcerate because of fecal matter banging up against it
What are some features of left sided CRC?
change in bowel habits, blood in stool, originates from ruptured vessels
obstructive, napkin ring
____________ kind of cancer develops in the rectum while ____________________ develops in the anus
How are GI tumors staged?
based on depth of invasion
Name 3 neoplasms of the appendix?
1) mucocele (benign dilatation of lumen by mucinous secretions)
2) mucinous cystadenoma (proliferation of benign neoplastic cells - dilatation by mucinous material)
3) mucinous cystadenocarcinoma (invasion fo neoplastic cells)