Path Lower Gi

Front 1

What are the 4 layers of the GI tract?

Back 1

Mucosa, submucosa, muscularis, serosa/adventitia

Front 2

What are the 4 layers of the mucosa?

Back 2

Epithelium, glands, lamina propria (loose ct below basement membrane), muscularis mucosa

Front 3

What are the different muscle layers of the muscularis typically and of the stomach and large intestine?

Back 3

Typically: inner circular, outer longitudinal
Stomach: inner circular, outer longitudinal, oblique
Large intestine: Circular, outer longitudinal, tenia coli

Front 4

What are the 3 regions of the small intestine?

Back 4

Duodenum, jejunum, ileum

Front 5

How often does epithelium of the small intestine regenerate?

Back 5

Every 72-96 hours

Front 6

What are 5 types of cells in the small intestine?

Back 6

Absorptice cells, goblet cells, panneth cells, endocrine cells, undifferentiated cells

Front 7

What are the absorptive cells of the small intestine?

Back 7

Enterocytes with microvilli to increase SA. Purpose: reclaim nutrients, fats, proteins digested from acids of pancreas and stomach

Front 8

What are two characteristics of goblet cells in the small intestine?

Back 8

Many more seen in large intestine than small intestine. The number of goblet cells increase as you move closer to the colon.

Front 9

What do goblet cells do?

Back 9

Secrete mucus

Front 10

What are panneth cells in the small intestine?

Back 10

Bright red cells at the bottom of the glands. Involved in host immunity where they detect and destroy bacteria

Front 11

What are endocrine cells?

Back 11

Individual cells that secrete hormones

Front 12

What are the major pathologies of the small intestine?

Back 12

Inflammatory disorders, infarctions, malabsorption, tumors of the SI (rare!)
The biggest problems with the SI are infarctions (more in elderly) and malabsorptions

Front 13

What are 3 congenital abnormalities of the small intestine?

Back 13

Atresia, stenosis and diverticula

Front 14

What is atresia of the small intestine?

Back 14

Segment of bowel is missing and has blind loops. Some w/ fibrous cord (w/ no lumen) in between. Typically identified first few days of life due to backup, bacterial overgrowth and many other issues

Front 15

What is stenosis of the small intestine?

Back 15

Narrow lumen of bowel which has a mild constriction to complete obstruction. Can be minor enough to never be picked up or diagnosed.

Front 16

What are the two types of intestinal diverticula?

Back 16

Congenital (True - Includes ALL 4 layers**) or False (herniation only of mucosa and submucosa)

Front 17

What is Meckel's Diverticulum?

Back 17

Persistence of vestige of omphalmesenteric duct.True diverticular structure. Ilium (1-3 ft from ileocecal valve) Few cm in length

Front 18

Why is the mucosa likely to be inflammed in Meckel's diverticulum?

Back 18

Can differentiate into gastric, pancreatic, duodenal, biliary or colonic mucosa/epithelium. Gastric/panc - SI will secrete acid rather than absorb --> perforation/ ulcerations. If differentiate into gastric epi --> will see rugal folds. Assoc w/ internal bleeding. Symptoms similar to acute appendicitis

Front 19

What are complications of Meckel's Diverticulum?

Back 19

Ulceration, perforation, fibrous adhesions.

* Ppl can live with this for a long time

Front 20

What are false diverticulum?

Back 20

Weak spots in the muscular wall (herniation only of mucosa and submucosa) Uncommon in SI but incredibly common in large intestine

Front 21

What are the complications of false diverticulum?

Back 21

Stasis --> increased bacterial growth, inflammatory response and potential perforation/bleeding, exudate (pus w/ involvement of inflammatory debris and fibrin). Perforation: fecal material can exit intestine

Front 22

What are 3 types of ischemic bowel disease?

Back 22

Infarction, hemorrhagic gastroenteropathy, chronic ischemia

Front 23

What are 3 types of infarctions?

Back 23

Transmural, mural, mucosal

Front 24

What is a transmural infarction?

Back 24

No layers spared. More common in SI than LI, dependent only on mesenteric vessels, usually involves 1 long segment of bowel

Front 25

What are 6 causes of transmural infarction?

Back 25

1. Arteriole thrombus or embolus of SMA/ IMA/ celiac (assoc w/ atherosclerosis),
2. "Watershed" areas - junction btwn 2 blood vessels supplying an area,
3. Hypotensive event (cardiac failure)
4. Vasospasm
5. Dissecting aortic aneurysm (separation of tunica intima and media or media and adventitia - separation will affect IMA and SMA,
6. Incarcerated hernia (clamping off blood supply)

Front 26

What is a mural infarction?

Back 26

Serosa is spared. Outer casing (simple squamous) still present. Serosa = last line of defense before contents get out of SI. Muscle can't regenerate so once affected, must be removed

Front 27

What is a mucosal infarction?

Back 27

Serosa AND muscularis spared. Will kill only mucosal surface. Mucosa CAN regenerate

Front 28

What are 4 causes of a mucosal infarction?

Back 28

1. Shock
2. Cardiac failure
3. Some meds lead to vasoconstriction
4. minute thrombi

Front 29

What is vulvulus?

Back 29

Bowel twists upon itself. Blood supply cute off. Tissue might look bright red. Can lead to mural and mucosal infarction (serosa, although dead, will still be intact). Sets stage for dilation leading to potential perforation.

Front 30

What is the mortaility rate in ischemic bowel disease?

Back 30

50-75% in older individuals

Front 31

What are the 4 main causes of ischemic bowel disease?

Back 31

Embolism (usually SMA), Volvulus, Intrasussception (telescoping/ prolapse of SI w/in itself), Incarcerated hernia sac

Front 32

What are the 4 main sources of embolism that causes ischemic bowel disease?

Back 32

Intracardiac thrombi, infective endocarditis, aortic aneurysms, atherosclerotic plaques

Front 33

What are the clinical manifestations of ischemic bowel disease?

Back 33

Abdominal pain, cramps, bloody discharge

Front 34

Is ischemic bowel disease reversible?

Back 34

Yes

Front 35

What are the benign tumors of the small intestine?

Back 35

Adenomas, leiomyomas, lipomas (multiple benign lipomas: interfere w/ SI avaialble for absorption)

Front 36

What are the malignant tumors of the small intestine?

Back 36

Adenocarcinoma (very rare, tend to be circumferential and focal), lymphomas, sarcomas (leiomyosarcoma: mucosa looks normal, tumor arising beelow epi)

Front 37

What is the most common tumor of the small intestine?

Back 37

Carcinoid tumor (endocrine in origin) - may see metastases

Front 38

What type of epi is the large intestine made of?

Back 38

Simple columnar epithelium

Front 39

What are the types of cells of the large intestine?

Back 39

Absorptive cells, goblet cells, endocrine, undifferentiated

Front 40

What do the absorptive cells in the Large intestine do?

Back 40

Reclaim water, do not have microvilli as seen in SI

Front 41

What do the goblet cells of the large intestine do?

Back 41

Pump out mucus for lubrication. Many more seen here than SI.

Front 42

What do the endocrine cells of the large intestine do?

Back 42

Pump out neuroendocrine hormones for bowel motility

Front 43

What is the purpose of undifferentiated cells?

Back 43

Regeneration to rebuild colon. Epi regenerates in 72-96 hrs

Front 44

What are the different muscle wall layers of the large intestine?

Back 44

Inner circular, outer longitudinal, tenia coli (3 small bands)

Front 45

What are 3 broad pathologies of the large intestine?

Back 45

Adenocarcinoma (leading source of cancer in the US), Inflammatory bowel disease, diverticular disease

Front 46

What are the 3 types of inflammatory bowel disease?

Back 46

Crohn's disease, ulcerative colitis, pseudomembranous colitis

Front 47

What are 2 characteristics of ulcerative colitis?

Back 47

Begins distally (rectum) and moves proximally. ONLY in the colon

Front 48

What are 5 symptoms of ulcerative colitis?

Back 48

Crampy abdominal pain, blood mucus diarrhea (Crohn's is only bloody, not mucus), Chronic persistent disease w/ exacerbations and remissions, begins in rectum and moves proximally, fulminate colitis rarely occurs

Front 49

What are the important things to note about the fact that ulcerative colitis begins in the rectum and moves proximally?

Back 49

It is continuous lesion w/ no skip lesions (as seen in Crohn's), primarily affects rectosigmoid colon and left/decending but entire colon may be involved, ilium may be involved in "backwash ileitis"

Front 50

What is fulminate colitis?

Back 50

Medical emergency: toxic dilation of colon that could lead to transmural inflammation, necrosis and perforation. Colonic resection necessary. Toxic megacolon: inflmmation cuts off peristalsis

Front 51

What layers of ulcerative colitis affect? Is it transmural?

Back 51

It may extend to the submucose, but transmural involvement rare. Doesn't involve muscularis except in severe cases.

Front 52

What would you see microscopically in ulcerative colitis?

Back 52

Vascular congestion w/ acute and chronic inflammation w/in mucosal layer. Cryptitis (neutrophils hang out in epithelium) and crypt absesses (neutrophils aggregate in crypts). NO granulomas! (as seen in Chrons)

Front 53

What is the treatment for Ulcertaive Colitis?

Back 53

Steroids for inflammation. Colonic resection. This would cure UC because UC only occurs in the colon!

Front 54

Can remission occur in UC?

Back 54

Yes, but not cured unless colon is removed. Always a "smoldering" inflammatory process going on. Colon carcinoma can be superimposed

Front 55

What are the chances of malignant transformation in UC?

Back 55

5% for adenocarcinoma. 30% for adenocarcinoma if disease >25 years. Biopsies evaluated for: dysplastic changes: pre-malignant change, and High Grade: high neoplastic transformation rate. High grade dysplasia and carcinoma = need proctocolectomy

Front 56

What are the characteristics of Chron's? (aka regional enteritis, granulomatous enteritis)

Back 56

Skip lesions, fibrous thickening of bowel wall and assic serositis, lumen of bowel stenotic, can be fistulas, FULL thickness inflammation, granulomas usually, can arise ANYWHERE in GI tract

Front 57

What are fistulas? And where can they occur in Chron's disease?

Back 57

Fistula = connection between 2 things that shouldn't connect. In Chron's, might see fistulas in bowel loops and surrounding structures (bladder, skin, vagina)

Front 58

Where are most Chron's lesions located? What are some other common locations?

Back 58

Most localized in the SI and ileocecal valve (70%). Some found only in colon (20-30%) But can be found anywhere in GI tract, even oral cavity.

Front 59

What are 4 clinical manifestations of Chron's disease?

Back 59

1. crampy abdominal pain,
2. bloody diarrhea (not mucous as w/ UC!)
3. obstruction (second to fibrous wall thickening)
4. Certain morphologies of the intestines

Front 60

What are some of the morphologies seen with Chron's disease?

Back 60

Peritoneal adhesions, serosa congested, fibrotic walls and assoc constriction, skip lesions, mucosa irregular w/ longitudinal ulcerations or fissues, lesions involve full thickness of wall, granulomatous inflmmation

Front 61

What is the treatment for Chron's disease?

Back 61

Resection of part of the cecum and part of the SI usually since this is where most UC cases are. Can reoccur through life.

Front 62

Would you want to resect the colon in someone with Chron's disease? Why or why not?

Back 62

In UC, you can resect the whole colon and attache SI to anal sphincter. In CD, this could cause the SI to be more affected by CD.

Front 63

What are the differences between CD and UC?

Back 63

In CD, transmural involvement, fissuring ulcers, granulomas, bowel obstruction, malabsorption, slight increase in colon carcinoma

Front 64

What kinds of malabsorption would you see in CD?

Back 64

Decrease in B12 absorption - decreased surface area for absorption.
Hypoalbuminemia (protein losing enteropathy) - not absorbed so more excreted.
Electrolyte disturbances

Front 65

What are 10 similarities between CD and UC?

Back 65

1. idiopathic. 2. acute&chronic w/ assoc ulcerations. 3. relapsing and remitting. 4. diagnosed age 15-35. 5. genetic predisposition. 6. immune mechanisms possibly involved. 7. other disorders assoc (migratory polyarthritis, sacroileitis, ankylosing spondylitis). 8. increase in US and Britain. 9. females more susceptible. 10. whites more susceptible.

Front 66

What is pseudomembranous colitis?

Back 66

Severe colitis in pts taking abx. Abx kills normal bacteria but some are not affected and take over. Usually C Diff. Bad diarrhea, sometimes including pus. Affects primarily ascending colon.

Front 67

What antibiotics can cause pseudomembranous colitis?

Back 67

Lincomycin, clindomyacin, ampicillin

Front 68

What mucosal changes occur in pseudomembranous colitis?

Back 68

Hyperemia, small gray/yellow plaques - "pseudomembrane", mucosa covered in fibrin, necrotic material, neutrophils. Acute inflammatory respone. Fibrin, mucous, polys of pseudomembrane erupt from crypts. Decreased peristalsys can cause increased toxins in area. Wall thickness down, dilation up.

Front 69

What is used to treat pseudomembrranous colitis?

Back 69

C Diff eradicated w/ vancomyocin.
*note: in past 5-6 years abx resistant c diff seen.

Front 70

What are diverticuli?

Back 70

Small out-pouching of mucosa that penetrate through muscularis

Front 71

Where are diverticuli located?

Back 71

Primarily in rectosigmoid area, but can be found anywhere in the colon. Prone to occur where muscle wall is weakened by penetrating vascular structures and increase of intraluminal pressure.

Front 72

What are the symptoms of diverticuli?

Back 72

Most clinically silent (only 20% ARE symptomatic!). Abdominal cramps, pain, discomfort, alternating constipation and diarrhea, feeling of incomplete bowel movements.

Front 73

When can problems with diverticuli occur?

Back 73

When material gets trapped - bacterial overgrowth, inflammation, fecalith formation. Can become diverticulitis.

Front 74

What is diverticulitis?

Back 74

Leukocytosis and fever (only 50%). Complications: Surrounding inflammatory reaction, may extend into surrounding fat, serosal adhesions can occur. fistulas and abscesses can form --> perforation, dense fibrotic reaction surrounding inflamed diverticulum - resemble carcinoma.

Front 75

What are benign tumors of the large intestines?

Back 75

Lipomas, leimyomas, angiomas, mesenchymal lesions, epithelial polyps

Front 76

What are non-neoplastic/benign polyps of the large intestines?

Back 76

Overgrowth of epithelium. Still have same genetic code of rest of normal epithelium, just overgrowth.

Front 77

What are 4 types of non-neoplastic/ benign polyps?

Back 77

Hyperplastic polyp (most common), inflammatory polyp, hamartomatous/ juvenile polyp, lymphoid poly

Front 78

What are hyperplastic polyps?

Back 78

Most common type of non-neoplastic benign polyps (90%). Typically asymptomatic. Only 15-20% of polyps removed are hyperplastic.

Front 79

What are the 3 types of neoplastic polyps of the colon?

Back 79

Tubular adenoma, villous adenoma, tubulovillous adenoma.

Front 80

Wht is tubular adenoma?

Back 80

75% of total neoplastic polyps. <1cm. If > 1cm = greater chance of caner. Only 1% chance of containing invasive carcinoma. Frequency increases after age 30, affects 2x men than women. Primarily in distal colon and rectom. 50% single lesion. Arise on a stock.

Front 81

What do you see microscopically in tubular adenomas of the colon?

Back 81

Stalk has normal colonic epi, while polypoid portion is overgrowth of tubular type glands. Can be as much as 25% transition to a villous architecture and still be considered tubular. Tubular adenoma cancer evolution LOW.

Front 82

What is villous adenoma?

Back 82

If villous architecture is >50% of polyp, considered villous adenoma. Usually over age 60. 75% located in rectosigmoid area, but also seen in ascending colon and cecum. Rectal bleeding w/ abundant mucous (protein losing enteropathy). Pre-malignant and 33% will contain invasive carcinoma.

Front 83

What is tubulovillous adenoma?

Back 83

Worse than butular adenomas but better than villous. Villous component = 20-25% of polyp. 0.5-5 cm in dm. can grow w/ or w/out a stalk. Morphology: can range from benign tubular epi to atypia, dysplasia or anaplasia w/ invasive carcinoma

Front 84

Relationship of polyps to carcinoma depends on:

Back 84

Size, portion of villous component:
->50% = 33% cancer risk, ->25% = 1% cancer risk. Degree of atypia and dysplasia.

Front 85

What is familial polyposis coli?

Back 85

Genetic component. Presence of polys in 100s-1000s throughout colon. Diagnosis: age 20-40. Most are tubular but may have villous features. HIGH risk for malignant transformation. Reaches 100% when >30 yrs from diagnosis.

Front 86

What type of tumors are 98% of all malignant tumors?

Back 86

Carcinomas (epithelial based)

Front 87

What is the incidence of colon carcinoma?

Back 87

3rd Most common cause of cancer related death in US. (lung - prostate/breast - colon). 15% of all cancer related deaths

Front 88

What are other malignant tumors of the colon?

Back 88

Malignant spindle tumors, Carcinoid tumors, squamous cell carcinoma, colacogenic or basaloid carcinoma, malignant melanomas

Front 89

Where do malignant spindal tumors of the colon come from?

Back 89

Arise from stromal elements (connective tissue)

Front 90

Where are carcinoid tumors of the colon found?

Back 90

Regions of the rectum

Front 91

Where are squamous cell carcinomas of the colon usually found?

Back 91

Anal canal area

Front 92

Where are colacogenic or basaloid carcinomas of the colon located?

Back 92

Rise in transition areas of squamo-columnar junction. Colacogenic carcinomas arise at PECTINATE line.

Front 93

Where are malignant melanomas of the colon usually located?

Back 93

Can arise from anal region

Front 94

What are the risk factors for adenocarcinomas of the colon?

Back 94

Low fiber intake, high refined carbo intake, high fat intake

Front 95

Why does the US have a high colorectal carcinoma rate?

Back 95

Diet! When immigrants come to US and adapt to our diet, their risk increases.

Front 96

Why does a low fiber, high refined carb diet lead to colon cancer?

Back 96

Low stool bulk, increased transit time, byproducts of refined carbs can have high conc of carcinogens, changes in colon flora.

Front 97

What other disease processes have a concordance with a low fiber diet?

Back 97

Appendicitis, diverticulosis, IBD

Front 98

What is the incidence and mortality rate like in colorectal carcinoma?

Back 98

Greater in blacks, greater in urban areas, most cases over age 50. Mortality rate has not changed much in 30-40 years. Even though earlier detection and better treatment, incidence is increasing.

Front 99

What are some characteristics of colorectal carcinoma?

Back 99

Typically it's circumfrential. Pt most likely presents w/ obstruction or bleeding and abdominal discomfort for a long time. Uniform thickening (makes hard to diagnose) = Linitis plastica. Rare in intestines, more common in stomach.

Front 100

What is modified dukes classification/ astor-collins modification of staging of malignant neoplasms in the colon?

Back 100

Dukes: devised 60 years ago. Evaluates level of extension through bowel wall into surrounding soft tissue and whether regional lymph nodes involved or distant metastases. Prognosis depends on stagin.

Front 101

What is the 1st year survival rate of malignant neoplasms in the colon?

Back 101

35-49%

Front 102

What is the morphology of malignant neoplasms of the colon?

Back 102

All lesions begin as in-situ mucosal cancer. Lesion progresses to invasive tumor - forms full circumfrence tumor and extends into surrounding soft tissue. Cancers of left colon differ from right

Front 103

What are colon cancers of the left colon like?

Back 103

Start out as raised, flat, expansile mass that expands through bowel wall as it encircles the lumen. Surface ulcerates when blood flow is interrupted. Lesion in rectosigmoid area tend to be more invasive and have worse prognosis.

Front 104

What are coln cancers of the right colon like?

Back 104

Tend to grow polypoid fungation masses that fill lumen. Both left and right can involve regional lymph nodes in late stages.

Front 105

What are the clinical manifestations of malignant neoplasms of the colon?

Back 105

Occult bleeding, changes in bowel habit, melena, constipation/obstrcution, diarrhea

Front 106

What clinical tests are used to diagnose malignant neoplasms of the colon?

Back 106

Digital exam protosigmoidoscopy, contrast radiographic studies, CT, blood test for CEA (not specific).
*Note: lesions on left detected earlier than on right

Front 107

What are lymphomas of the colon?

Back 107

Tumors that arise from the mesentary

Front 108

What is melanosis coli?

Back 108

Not tumors. Immobility usually secondary to laxative overuse. Color changes to much darker/grayer.