Gih Week 2: Small Bowel/colon Holliman

Front 1

What condition is characterized by failure of one or more segments of small bowel to develop a lumen.

Back 1

Small bowel atresia

Front 2

What is an early clinical symptom of small bowel atresia?

Back 2

Persistent vomiting of bowel-stained material

Front 3

What events can result in imperforate anus?

Back 3

1. Failure of anal membranous septum to develop
2. Agenesis
3. Atresia
4. Stenosis

Front 4

What disease is referred to as "congenital megacolon?"

Back 4

Hirschsprung disease

Front 5

What is the etiology of Hirschprung disease?

Back 5

Failure of neural crest cells to migrate to the myenteric (Auerbach) and submucossal (Meissner) plexuss in the distal colon during embryologic development.

Front 6

Which portion of the GI tract is usually involved in Hirschsprung disease?

Back 6

Rectum and sigmoid
(Anorectal junction always involved)

Front 7

In Hirschsprung's disease, where does dilation of the colon occur relative to the aganglionic segment?

Back 7

Dilation of colon proximal to aganglionic segment

Front 8

Is Hirschsprung's disease more common in males or females?

Back 8

Males

*Also may be associated w/ Down syndrome

Front 9

Where do pulsion diverticula of small bowel tend to occur?

Back 9

Along the mesenteric border

Front 10

What is a Meckel diverticulum?

Back 10

Persistence of the proximal portion of the omphalomesenteric (Vitelline) duct, which embryologically linked to the yolk sac.

Front 11

Along which border of the small bowel are Meckel diverticula seen?

Back 11

Antimesenteric border of the ileum

Front 12

How do the locations of pulsion diverticula and Meckelf diverticula differ?

Back 12

Puslion diverticum--> mesenteric border of small bowel

Meckel diverticulum--> anti-mesenteric border of ileum

Front 13

What sort of heterotopic tissue is often present in Meckel diverticula, and what conditions can result from this tissue?

Back 13

Hetertopic gastric mucosa
Can result in:
1. Peptic ulceration -->
2. Bleeding -->
3. Iron deficiency anemia
4. Scarring --> bowel obstruction

Front 14

How does age correlate to diverticular disease of the colon?

Back 14

More prominent with increasing age

Front 15

Describe the events that lead to "prediverticular disease" and "diverticulosis."

Back 15

Hypertrophy of circular/longitudinal muscular layers--> "prediverticular disease"

Subsequent herniation of the mucosa and submucosa through the colon wall --> "diverticulosis"

Front 16

Where do most diverticula occur along the colon?

Back 16

Sigmoid colon (95%)

Front 17

Are most colon diverticula symptomatic or asymptomatic?

Back 17

Asymptomatic

If symptoms do occur they are usually:
1. Lower abdominal pain
2. Constipation
3. Distension
As disease progresses:
1. Abdominal cramps
2. Worsening constipation
3. Bleeding

Front 18

Where might a mass be palpable if a patient has diverticular disease of the colon?

Back 18

Lower left quadrant
(usually associated w/ sigmoid colon)

Front 19

What are the clinical indicators of acute diverticulitis?

Back 19

1. Fever
2. Leukocytosis

May result in pericolic abscesses, peritonitis, sinus/fistula tracts

Front 20

What condition results from abnormal embryologic rotation of the ventral pancreatic bud, causing it to encircle the duodenum before fusing with the dorsal bud?

How does this effect the duodenum?

Back 20

Annular pancreas

Leads to partial obstruction of duodenum

Front 21

What term refers to ectopic pancreatic tissue that typically occurs in the duodenum?

Back 21

Pancreatic rest

(May elevate the mucosa and might stimulate a neoplastic process)

Front 22

Serosa-lined protrusion of peritoneum occurring in areas of weakness along the abdominal wall.

Back 22

Abdominal hernia

*Segments of bowel may enter these sacs--especially during periods of increased intra-abdominal pressure

Front 23

What can cause the development of fibrous adhesions?

Back 23

Peritonitis of any cause (bacterial, surgical, etc.)

Front 24

Where do fibrous adhesions occur?

Back 24

Between loops of bowel or between bowel and abdominal viscera or peritoneal wall.

Front 25

Medical condition in which a part of the intestine has invaginated into another section of intestine, similar to the way in which the parts of a collapsible telescope slide into one another.

Back 25

Intussusception

Front 26

Intussusception usually involves the telescoping of what portion of the bowel?

Back 26

Telescoping of terminal ileum into the cecum

*Usually occurs in children

Front 27

What is the most frequent cause of intussusception in children?

In adults?

Back 27

Children--> Hyperplasia of Peyer's patches

Adults --> polyps or tumors which get caught up in peristaltic action

Front 28

How should you treat intussusception in children?

In adults?

Back 28

Children--> barium enema or abdominal palpation

Adults --> surgical intervention

Front 29

The result of the cecum failing to descend to the right lower quadrant during development.

Why might this be of clinical significance?

Back 29

Malrotation

Could obscure the diagnosis of acute appendicitis since the appendix does not lie in its characteristic location.

Front 30

What condition is associated with chronic anthracene laxative abuse?

Back 30

Melanosis coli

Front 31

What causes the discoloration of the colon in Melanosis coli?

Back 31

Apoptosis of colonic epithelium results in the brown-black pigment and is digested by macrophages in the lamina propria

Front 32

*
What clinical symptoms characterize malabsorptive disorders?

Back 32

1. Anemia
2. Muscle wasting
3. Weightloss
4. Borborygmi (growling stomach)
5. Abdominal distension
6. Abnormal stools (steatorrhea, diarrhea)

Front 33

*
Where does most absorption occur in the GI tract?

Back 33

Duodenum and jejunum

Front 34

*
Where are Vitamin B12 and bile salts absorbed in the the GI tract?

Back 34

Ileum

Front 35

What causes Celiac disease?

Back 35

Immunologic hypersensitivity to gliadin which induces increased levels of IgA and IgM in the intestinal mucosa

Front 36

What is the result of Celiac disease on the GI tissue?

Back 36

1. Accelerated sloughing of jejunal epithelium--> severe atrophy of villi --> decreased absorptive surface area
2. Epithelial hyperplasia --> increased depth of intervillous crypts
3. Increased chronic inflammatory cell infiltration

Front 37

What symptom is usually the presenting complaint of Celiac disease?

Back 37

Diarrhea
(although anemia is often present)

Front 38

What dietary eliminations must be made to restore normal physiologic function in patients with Celiac disease?

Back 38

Eliminate
1. Wheat
2. Oats
3. Barley
4. Rye products

Front 39

Patients with Celiac disease are at increased risk of what types of neoplasias?

Back 39

1. Small bowel lymphoma
2. Adenocarcinoma

Front 40

What clinical signs are characteristic of Topical sprue?

Back 40

1. Steatorrhea
2. Folate deficiency anemia

Front 41

What is the most likely cause of Tropical sprue?

Back 41

Unclassified bacterial enteritis

Front 42

Histologically, what is a major difference between Tropical sprue and Celiac disease (non-tropical sprue)?

Back 42

The location of the involved intestines is different:
Tropical sprue--> Uniformly affects small bowel or is more severe in DISTAL bowel
Celiac disease --> Most severe in UPPER jejunum

Front 43

How can patients be cured from Tropical sprue?

Back 43

Broad-spectrum antibiotic treatment and folic acid supplementation

Front 44

What is the causative organism of Whipple disease?

Back 44

Tropheryma whippelii

Front 45

How can Whipple disease often be cured?

Back 45

Antibiotic therapy

Front 46

What is the characteristic feature of Whipple disease?

Back 46

Presence of macrophages filled with PAS-(+), diastase-resistant granules in the lamina propria of small bowel.

PAS- Periodic Acid Schiff
Diastase-resistant granules = macrophage lysosomes with bacteria inside

Front 47

*
Is bacterial infection usually a primary or secondary event in acute appendicitis?

Back 47

Secondary

(Local event--some sort of obstruction is usually the primary event)

Front 48

What symptoms clinically characterize Appendicitis?

Back 48

1. Diffuse abdominal pain that eventually localizes to lower right quadrant (McBurney point)
2. Nausea
3. Vomitting
4. Anorexia
5. Diarrhea/constipation

Front 49

List 3 general theories that could explain the cause of inflammatory bowel disease.

Back 49

1. Genetic predisposition
2. Infectious agent
3. Autoimmune disorder

Front 50

Crohn's Disease is more common in what people?

Back 50

Females
(peak incidence in adolescent-young years)

Front 51

What is the characteristic morphology of Crohn's disease?

Back 51

Segmental ("skip lesions") of the bowel

Front 52

What portion(s) of the intestines are usually involved in Crohn's disease.

Back 52

Usually both small and large bowel are involved

Front 53

Transmural thickening and fibrosis of the bowel wall with narrowing of the lumen is classically seen in what disease?

Back 53

Crohn's disease

Front 54

Cobblestone mucosa and creeping fat are characteristics of what disease?

Back 54

Crohn's disease

Cobblestone mucosa--> linear, serpentine ulcerations of the mucosal surface

Creeping fat--> fibrotic mesenteric fat

Front 55

Non-caseating granuloma formation is characteristic of what disease?

Back 55

Crohn's disease

Front 56

Some studies suggest the Crohn's disease might be related to what infection?

Back 56

Persistent measles virus infection

Front 57

What sort of malaborption is seen in Crohn's disease?

Back 57

1. Protein
2. Vitamin B12
3. Folic acid
4. Iron

Front 58

Crohn's disease subjects patients to an increased risk of what type of cancer?

Back 58

Adenocarcinoma of the colon

Front 59

An acute and chronic inflammatory disease that results in extensive ulceration of the mucosal surfaces of the colon (and sometimes terminal ileum).

Back 59

Ulcerative colitis

Front 60

Where does ulcerative colitis always begin?

Back 60

Rectum
(spreads proximally)

Front 61

What is it called when ulcerative colitis spreads into the terminal ileum?

Back 61

"backwash ileitis"

Front 62

What do the early lesions of ulcerative colitis begin as?

Back 62

Small mucosal hemorrhages and *crypt absesses

Front 63

In ulcerative colitis, what structures may form on the rare occasion that crypt absesses extend through the muscularis propria?

Back 63

Pericolic abscesses

Front 64

Inflammatory pseudopolyps are seen in what disease?

Back 64

Ulcerative colitis

(These are residual islands of edematous, inflamed mucosa)

Front 65

What disease often presents with abdominal pain, cramps, and bloody diarrhea?

Back 65

Ulcerative colitis

(*Usually manifests in early adulthood: 20-40 years)

Front 66

During acute attacks, toxic megacolon can be seen in what disease?

How is this treated?

Back 66

Ulcerative colitis

*Immediate surgical intervention

Front 67

Is malignant transformation more common in Crohn's disease or ulcerative colitis?

Back 67

Ulcerative colitis
(risk is dependent on duration, age of onset, chronicity, extent)

Front 68

Presence of membrane-like inflammatory exudate, which is patchily distributed over mucosal surface of the colon (and sometimes small bowel).

Back 68

Pseudomembranous colitis

Front 69

What is the inflammatory exudate composed of in pseudomembranous colitis?

Back 69

1. Mucin
2. Neutrophils
3. Fibrin

Front 70

What is physically underlying the membrane formed in pseudomembranous colitis?

Back 70

Inflammatory infiltrates and varying degrees of mucosal necrosis

Front 71

What pathogolic agent is associated with pseudomembranous colitis?

How does this agent cause destruction?

Back 71

Clostridium difficile

*Bacteria exotoxins bind to colonic epithelial cells causing hypersecretion and inducing a suppurative inflammation w/ focal mucosal necrosis

Front 72

What factors may predispose a person to pseudomembranous colitis?

Back 72

1. Antibiotic use (especially Clindamycin and Lincomycin)
2. Severe trauma
3. Medical/surgical illness

Front 73

Pseudomembranous colitis can take on two different courses following antibiotic therapy. Describe the symptoms associated with these courses.

Back 73

1. Profuse diarrhea developing DURING antibiotic therapy (resolves within 2 weeks after discontinuation)

2. Copious bloody diarrhea which develops many days AFTER antibiotic therapy has been completed. May lead to electrolyte imbalance and possible death.