This condition is when the peritoneum protrudes through an opening, causing an obstruction.
Hernia
This is the condition 2 segments of the intestine fuse as a result of peritoneal inflammation
Adhesions
This is the condition where a portion of the bowel twists around itself and can cause an obstruction.
Volvulus
This is the condition where 1 bowel segment telescopes on itself.
Intussception
What can happen to the bowels of there is an infarct in the celiac, SMA, or IMA?
Ischemia
This injury occurs at the onset of vascular compromise.
Initial hypoxic injury
This injury in IBD occurs when there is a restoration of blood supply.
Reperfusion injury.
What substances cause the reperfusion injury in IBD
free radicals
The splenic flexure, sigmoid colon, and surface epithelium are at risk for ischemic injury because of what feature of the arterial supply?
they’re in watershed zones.
What are the morphological features of the wall of the bowel in IBD?
it becomes edematous, thick, and rubbery with coagulative necrosis of the muscularis propria
Patients with what pre-existing constions are susceptible for IBD?
cardiac or vascular disease
This is the condition when tortuous dilation of submucosal vessels leads to hematochezia.
Angiodysplasia
Where is angiodysplasia present in the bowels?
Lower stuff (cecum, terminal ileum, ascending colon)
This is the condtion hallmarked by steatorrhea, and symptoms include weight loss, anorexia, abdominal distention, borborygmi, and muscle wasting.
Malabsorption
This condition is a result of Ab development against gliadin, leading to immune destruction of mucosal cells.
Celiac disease
Along with atropy of the villi, which WBC do you see in the lamina propria in celiac disease?
Plasma cells.
Pt’s with celiac disease have an increased risk of what type of lymphoma?
small bowel T-cell lymphoma
Case: a patient comes into the office complaining of malabsorption. You do an endoscopic exam and realize the entire small bowel has sprue, instead of just in the distal ileum and jejunum. Labs show abnormal d-xylose and antiglidin Ab’s. What is the probable cause of this disease?
Bacterial inflammation (tropical sprue)
This condition is an X-linked disorder characterized by severe persistent diarrhea, especially in young children.
Autoimmune enteropathy
What is a severe form of autoimmune enteropathy?
IPEX syndrome
What gene is at fault to cause the IPEX syndrome?
FOXP3
This type of lactase insufficiency produces explosive diarrhea with watery and frothy stools due to an ER mutation in the lactase gene.
Congenital lactase deficiency
This type of lactase deficiency is from down-regulation of the lactase gene, present after childhood, and presents as abdominal fullness, diarrhea, and farting.
Acquired lactase deficiency
What happens if you cannot synthesize apolipoprotein B? What happens to fat absorption?
You can absorb fat into your intestinal epithelia but cannot get it out cuz u cant make chylomicrons
What are the Sx of abetalipoproteinemia?
early childhood malabsorption, failure to thrive, diarrhea/steatorrhea, and neuro manifestations
This organisms enterotoxin causes severe ricewater stools.
Vibrio cholera
What does cholera stimulate excessively in the cells to cause the severe watery diarrhea?
Adenylate Cyclase
This organism produces crypt abscesses after it invades the SI and colonic mucosa.
Campylobacter jejuni
jejuni b/c jejunum!
This genre of bacteria target the ileum and left colon and produce mucosal ulceration and pseudomembranous inflammation.
Shigella
Shigellosis
What is the main salmonella species to cause acute limited colitis, kinda like Campy and Shigella?
S. enteriditis (non-typhoidal)
What happens during the first week of S. typhi infections (typhoid fever)?
(think pathogenesis)
it attaches and invades the terminal ileum over Peyers patches, get ulcers, and produces septicemia.
What happens during the 2nd week of S. typhi infections (typhoid fever)?
(think Sx)
diarrhea, bradycardia, neutropenia and hepatosplenomegaly with typhoid nodules.
This genre of bacteria invade M cells and use adhesion proteins to cause regional lymph node and Peyes patch hyperplasia and bowel wall thickening.
Yersinia
What is the role of the heat-labile toxin (LT) for Enterotoxigenic E. Coli?
stimualtes cAMP –> secretory diarrhea, normal mucosa
What is the role of the heat-stable toxin (ST) for Enterotoxigenic E. Coli?
stimulates guanylate cyclase –> increase cGMP –> secretory diarrhea
What is the serotype of EHEC?
O157:H7
What are the Sx to EHEC infections?
uremic syndrome, bloody diarrhea, hemorrhagic or pseudomembranous colitis
What are the Sx to EIEC infections?
bloody diarreha, mucosal necrosis and inflammation. invasion of the lower intestine
What is the pathogenesis for EAEC?
attach to enterocytes using fimbrae and dispersin –> produce enterotoxin –> non-bloody diarrhea
This bacteria produces a toxin in the colon and causes watery smelly diarrhea, fever, and pain.
C. diff
This disease is characterized by fever, diarrhea, joint pain, emaciation, skin pigmentation, lymphadenopathy, and neurological abnormalitis.
Whipple disease
T. whippeli
What is the characteristic finding in the lamina propria in whipple disease?
PAS-positive foamy macrophages
What virus causes watery, nonbloody diarrhea in kids by infecting and damaging bursh border enzymes?
Rotavirus
What virus causes gastroenteritis in adults?
Norwalk virus
Which virus causes epithelial degeneration but often non-villous atrophy and crypt hyperplasia, tpyically in kids and the military?
Adenovirus
This nematode causes hepatic abscesses and induces a eosinophil-rich inflammatory rxn?
Ascaris lumbricoides
Where does strongyloides infect?
it causes peripheral eosinophilia and induces inflammatory infiltrates in the lungs and residues in the intestine
What are the 2 hookworms?
Necator duodenale and ancylostoma duadenale
What is the pathogenesis to hookworms?
They “hook” onto duodenal mucosa and such blood –> superficial erosions focal hemorrhage + inflammatory infiltrates
What is the genre fro pinworms?
Enterobius vermicularis
True or False: pinworms rarely cause disease cuz they live their entire life in the intestinal lumen
True
How do you Dx pinworms?
put tape on your b-hole and look for huevos
What is the genre fro whipworm?
Trichuris trichiura (tricky tricky)
This parasite resides in mesenteric veins and their eggs get reapped in the mucosa and submucosa –> immune rxns –> granulomas, bleeding and obstruction.
Schistosomiasis
Diphyllobothrium, taenia solium, and hymenolepsis are all types of what parasitic infection?
Tape worm
What are the Sx of tapeworm infeciton?
abdominal pain, diarrhea, and nausea
What is the parasite that causes dysentary/amebiasis?
Entamoeba histolytica
How does entamoeba cause ulcerations of the colon?
cyts colonize –> apoptosis in lamina propria –> neurotphils recruit –> tissue dmg –> flask shaped ulcer
What is the pathogenesis of giardia lamblia to cause acute or chronic diarrhea?
it decreases production of brush0border enzymes –> microvillous dmg –> apoptosis of SI epithelial cells
How does cryptosporidium cause watery diarrhea?
induces actin polymerization on enterocytes –> engulfment of parasite –> Na malabsorption + Cl secretion –> watery diarrhea
weirdo.
This condition is when there is an abnormality in colonic motility that is commonly precipitated by stress or consumption of high fat meals.
Irritable Bowel Syndrome (IBS)
What are the Sx to IBS?
alternating bouts of diarrhea and constipation, cramping, abd pain, tenesmus, mucous in the stool, and pain relieved by bowel mvmt.
my ex-gf had IBS and it was super annoying. she’d blow up my toilet on the reg. that’s why we’re no longer together.
You think I’m joking.
I’m not.
This is the condition resulting from inappropriate mucosal immune activation.
Inflammatory Bowel Disease (IBD)
What are the 2 classical IBD’s?
Crohn’s disease and Ulcerative Colitis
This IBD is when there is severe ulcerating inflammatory disease that is limited to the colon and rectum and extends only from the mucosa to the submucosa.
Ulcerative Colitis
literally meaning, “ulcers in the inflamed colon”
This IBD is regional in the GI tract and is transmural.
Crohns disease
What types of people are susceptible to IBD?
young white females.
esp Ashkenazi jews.
Case: you do a colonoscopy and find a patch in the colon with far creeping around the serosa, thick bowel wall and narrow lumen, ulcers, and strictures. Which disease are u thinking could be the cause?
Crohns disease
Case: on a different colonoscopy, in the rectum you find inflammatory polyps friable mucosa, uceration and hemorrhage. What is the etiology?
Ulcerative colitis.
So which one is caused by a disordered response to bacteria, Crohns or Ulcerative colitis?
Crohns
So which one is caused by an immune response, Crohns or Ulcerative colitis?
Ulcerative colitis
So you finally treat the ulcerative colitis surgically, but now the patient is at risk for what other type of colitis where an ostomy forms?
Diversion colitis
This is the colitis when there is a presence of a dense subepithelial collagen layer, increased # of intraepithelial lymphocytes, and inflammatory infiltrate in the lamina propria.
Collagenous colitis
What is the condiiton when the collagen layer is of normal thickness and there is an increase in lymphocytes?
Lymphocytic colitis
What type of colitis formed after bone marrow transplant, and there is epithelial apoptosis of crypt cells over the SI and colon?
Graft-vs-host disease
This is an outpouching of the lower colonic mucosa and submucosa.
Sigmoid diverticulitis
What is the main cause of sigmoid diverticulitis?
icnreased intraluminal pressure
Which quadrant in the abdomen will a patient present with pain from sigmoid diverticulitis?
LLQ
What are sessile polyps?
Those that have a broad base that’s firmly attached ot the mucosa
What are pedunculated polyps?
Those that have a stalk
What type of polyps form with soltary rectal ulcer syndrome?
inflammatory polyps
think ulcers = inflammation
The impaired relaxation of what sphincter causes recurrent abrasions and thus inflammatory polyps and the solitary rectal ulcer syndrome?
rectoanal sphincter
Which polypsoccur sporadiccally and in the context of various genetic or acquired syndromes?
Hamartomatous polyps
These are polyps that form reddish-brown, round, smooth polyps on the rectum of kids.
Juvenile polyps
If there is only 1 juvenile polyp, is there an increased risk for adenocarcinoma?
no
This AD disease is assocated with multiple non-malignant hamartomatous polyps in the SI, colon and stomach.
Peutz-Jeghers syndrome
IN PJS, there is pigementation of what epithelial tissues?
Lips, mouth, hands, and genetalia
This Ad syndrome is characterized by macrocephaly, intestinal hamartomatous polyps, and benign skin tumors.
Cowden syndrome.
Which 3 carcinomas does Cowden syndrome predispose you for?
breast, thyroid, and endometrial carcinoma.
Which syndrome has mental deficiencies, developmental delays, and lower instances of neoplasia as compared to Cowden syndrome?
Bannayan-Ruvalcaba-Riley Syndrome
YEAH LETS PUT ALL OUR LONG NAMES TOGETHER FOR 1 THING
True or False: Cronkhite-canada syndrome has no hereditary disposition and is assocaited with juvenile type polyps throughout the intestines.
True
What is the most common polyp in the colon?
Hyperplastic polyp
What causes hyperplastic polyps to form?
A defect in maturation of the epithelial cells
What do hyperplastic polyps look like histologically?
hyperplastic epithelium with a sawtooth appearance
True or False: any neoplastic mass lesion in the GI may produce a polyp.
True
Colonic adenomas cause benign polyps that are precursors to what type of cancer?
colorectal adenocarcinomas
Colorectal adenomas are characterized by the presence of what abnormal epithelial growth?
epithelial dysplasia
What is the most common polyposis syndrome?
Familial adenomatous polyposis (FAP)
What # of polyps must u have to be diagnosed as having FAP?
> 100
Is FAP autosomal dominant or recessive?
AD
What gene is suppressed in FAP?
APC supressor gene
By 40 years old, what % of FAP patients will have cancer?
100%
This condition is when there is familial clustering of cancers at several sites in the body, from mutations in DNA repair mechanisms.
Hereditary non-polyposis colorectal cancer
Lynch syndrome
What is the genetic defect to cause colonic adenocarcinoma development via the WNT pathway?
APC/B-catenin pathway
What is the genetic factor to cause defects in DNA mismatch repair, leading to colonic adenocarcinomas?
Microsatellite instability pathway
What are the clinical features of right-sided colonic adenocarcinomas?
polypoid appearance, usually bleed
What are the clinical features of left-sided colonic adenocarcinomas?
napkin ring/apple-core lesion due to smaller diameter, constipation (obvi)
These are tumors of the anal canal which are populated by immature cells derived from the basal layer of transitional epithelium.
basaloid tumors
Pure squamous cell carcinomas of the anus are associated with what infection?
HPV
The classification of hemorrhoids (internal/external) are based off which line?
Pectinate line
True or false: all hemorroids present with pain or itching.
False. internal do not.
60% of acute appendicitis is caused by fecalith blockage of what part of the intestine?
Lumen to the appendix
What WBC invades the appendix in acute appendicits?
Neutrophils
What forms in the walls in acute supporative appendicitis?
focal abscesses
What happens to the appendix in acute gangenous appendicits?
there are large areas of ulceration and gangenous necrosis that extends to the serosa.
Which sign can u use for acute appendicits in clinical exam?
McBurneys sign
What is the most common tumor of the appendix?
Carcinoid tumor