Lower Gi Pathology

Front 1

Absorptive Cells (Small Intestine)

Back 1

Enterocytes with microvilli to increase the surface area for the purpose of absorbing nutrients.

Front 2

Goblet Cells (Small Intestine)

Back 2

Secrete mucous for lubrication

Front 3

Panneth Cells (Small Intestine)

Back 3

Recognized infectious agents

Front 4

Endocrine Cells (Small Intestine)

Back 4

Produce Hormones

Front 5

Peristalsis

Back 5

Contraction of two layers of muscle - circular and longitudinal - that moves nutrients through the intestines

Front 6

Small Intestine Atresia

Back 6

Congenital Abnormality in which a segment of the bowel is missing and has blind loops...sometimes with fibrous cord in-between.

Front 7

Small Intestine Stenosis

Back 7

A congenital narrowing of the bowel lumen ranging from mild obstruction to complete blockage.

Front 8

Small Intestine True Diverticulum

Back 8

A congenital defect of the small intestine in which all four layers of the bowel wall form an abnormal out pouching.

Front 9

Small Intestine False Diverticulum

Back 9

Arise from weak sport in the muscular wall in which the mucosa and submucosa herniate through the weak point.

Hint 9

**More common in the colon.
**Complications:
- Stasis leading to increased bacterial growth.
- Inflammatory Response
- Perforation and bleeding

Front 10

Meckel's Diverticulum

Back 10

A true diverticulum of the small intestine that occurs 1-3 feet proximal to the ileocecal valve. It is usually a few cm in length and usually has associated inflammation of the mucosa.

Hint 10

**Mucosa can differentiate into gastric, pancreatic, duodenal, biliary, or colonic mucosa
**Associated with internal bleeding
**Symptoms are similar to acute appendicitis and can include ulceration and perforation.

Front 11

Diverticular Structures

Back 11

Outpouchings - true or false - that can be found in the small or large intestines.

Hint 11

**Feces can get stuck in the out pouching and cause inflammation.
**Can develop rugal like folds that can secrete acids similar to that of the stomach causing inflammation.

Front 12

Ischemic Bowel Disease of the Small Intestine

Back 12

A condition in which the vascular flow to the small intestine is compromised.

Hint 12

1. Infarction
2. Hemorrhagic Gastroenteropathy
3. Chronic Ischemia

Front 13

Three Types of Small Intestine Infarction

Back 13

1. Transmural
2. Mural
3. Mucosal

Front 14

Transmural Infarction

Back 14

Infarction of the bowel which extends through all four layers of the GI wall. Is solely dependent on the mesenteric vessels that are blocked (arterial thrombus or embolus) such as the SMA, IMA, or celiac trunk.

Hint 14

**More common in the small
**Usually involves one long segment of the bowel
**Associated with artheroschlerosis
**Under a hypotensive event - ie cardiac failure, dissecting aortic aneurysm, incarcerated hernia - you will get a drop off of blood flow to these "watershed" areas.

Front 15

Mural Infarction

Back 15

Blockage of blood flow to the bowel in which the serosa is spared.

Front 16

Mucosal Infarction

Back 16

Blockage of blood flow to the bowel in which the serosa and muscular is is spared.

Hint 16

**Causes
- Shock and cardiac failure
- Digitalis can lead to vasoconstriction of vessels
- Minute thrombi

Front 17

Causes of Ischemic Bowel Disease

Back 17

1. Embolism (SMA involved)
2. Intracardiac thrombi
3. Infective Endocarditis
4. Aortic Aneurysm
5. Atherosclerotic Plaques
6. Volvulus
6. Intrasussecption
7. Incarcerated Hernia Sac

Front 18

Volvulus

Back 18

Bowel twisting on Itself

Front 19

Bowel Intrasussecption

Back 19

The bowel prolapses on itself like a telescope.

Front 20

Incarcerated Hernia Sac

Back 20

Bowel goes into any type of hernial sac - i.e. femoral, direct, indirect - causing a blockage of blood supply and can result in ischemic bowel disease.

Front 21

Clinical Implications of Ischemic Bowel Disease

Back 21

1. Abdominal Pain
2. Cramps
3. Bloody Discharge
**It is reversible

Front 22

Small Intestine Adenoma/Adenocarcinoma

Back 22

Benign/malignant tumor of the glandular epithelium of the small intestine

Hint 22

**Tumors of the small intestine are very rare!

Front 23

Small Intestine Leiomyomas/sarcomas

Back 23

Benign/malignant tumor of the smooth muscle in the muscular is layer of the GI tract.

Front 24

Small Intestine Lipoma

Back 24

Benign tumor of the fat cells surrounding the small intestine.

Hint 24

**Although benign, immensely prevalent lipomas on the small intestine can drastically reduce the surface area available and lead to malabsorption.

Front 25

Small Intestine Carcinoid

Back 25

The most common malignant tumor of the small intestine and involves neuroendocrine cells.

Front 26

Large Intestine Simple Columnar Epithelium Types

Back 26

1. Absorptive - Reclaim Water
2. Goblet - Much high proportion/secretion than small bowel
3. Endocrine Cells
4. Undifferentiated Cells

Hint 26

**Colonic Cells regenerate every 72-96 hours.

Front 27

Tenia Coli

Back 27

Longitudinal running muscles that run the length of the colon.

Front 28

Large Intestine Diverticulosis

Back 28

Predominately a false diverticulum in which the mucosa and submucosa push through a weakened muscularis layer. Weakness can arise from penetrating vascular structures and increased intraluminal pressure.

Hint 28

**Most commonly occure in the rectosigmoid region of the colon.
**Incidence increases with age, but only 20% have manifestation because fecal matter is usually squeezed out.
**May progress into diverticulitis if sites has bacterial overgrowth, inflammation, and fecalith formation.

Front 29

Large Intestine Diverticulitis

Back 29

Inflammatory reaction surrounding a chronic and bacteria filled diverticulum.

Hint 29

**Inflammation may extend into the surrounding fat forming serial adhesions.
**Fistula tracks and abscesses may form that could lead to perforation.
**Dense fibrotic changes surrounding the inflammation may resemble a carcinoma.

Front 30

Pseudomembranous Colitis

Back 30

When taking a broad spectrum antibiotic it wipes out all bacteria allowing the naturally growing Claustridium Difficile to take over and cover the entire lining of the colon and cause severe inflammation.

Hint 30

**Primarily affects the R. Colon
**Main symptom is diarrhea that may include pus.
**Presence of small plaques that may coalesce to completely cover the mucosal with a "pseudomembrane"
**Mucosa is covered in fibrin, necrotic material and neutrophils.

Front 31

Fulminate Colitis

Back 31

A rarely occurring medical emergency associated with Ulcerative Colitis in which there is a toxic dilation of the colon leading to transmural inflammation, necrosis, and perforation. This leads to lack of peristalsis and can rupture. Colonic resection is necessary.

Front 32

Benign Tumors of the Small Intestine

Back 32

1. Lipomas
2. Leiomyomas
3. Angiomas
4. Mesenchymal Lesions
5. Epithelial Polyps

Front 33

Polyp

Back 33

Extension of the mucosal layer of the GI tract that can either be non-neoplastic or neoplastic.

Front 34

Hyperplastic Polyp

Back 34

The most common (90% of all epithelial polyps in the GI) type of non-neoplastic polyps.

Hint 34

**Usually asymptomatic and when removed are investigated for neoplastic feature.
**Only 15-20% of all polyps removed are hyper plastic.

Front 35

Tubular Adenoma

Back 35

The most common benign neoplastic polyp most prevalent in the rectum and distal colon that arises on a stalk (pedunculated).

Hint 35

**75% of neoplastic polyps
**2:1 men:women increasing after age 30
**Stalk has normal colonic dpi while the polypoid is an overgrowth of tubular type glands
**You can have 25% transition to villous architecture and still be called tubular adenomas
**Greater than 1cm = increased risk of cancer

Front 36

Villous Adenomas

Back 36

Neoplastic polyp found mostly in the recto-sigmoid area which contains over 50% villous architecture - large, sessile, covered in thin villi -

Hint 36

**Usually occur in patients >60
**Premalignant = 1/3 of them will have an invasive carcinoma
**Responsible for rectal bleeding, sometimes with abundant mucous.

Front 37

Tubulovillous Adenoma

Back 37

Neoplastic polyp consisting of 25-50% villous component and can grow with or without a stalk.

Hint 37

**Cells can range from benign tubular to anaplasia with invasive carcinoma.
**Microscopic evaluation is essential.

Front 38

Familial Polyposis Coli (FAP)

Back 38

The presence of 100's-1000's of neoplastic polyps in the colon that are mostly tubular adenomas with some villous features that has a 100% chance of becoming a malignant colon cancer.

Hint 38

**Diagnosed between 20-40
**Seems to be an inherited disorder and thus family members should be examined as early as 15yo
**Prophylactic Colectomy is warranted.

Front 39

Large Intestine Malignant Neoplasms

Back 39

Malignant tumors that originate from the large intestine.
**98% of malignant colon tumors are adenocarcinomas!!

Hint 39

**It is the third most common cause of mortality in the US
**Causes 15% of all cancer related deaths.

Front 40

Three types of disease processes of the large colon

Back 40

1. Adenocarcinoma
2. Inflammatory Bowel Disease
3. Diverticular Disease