Pathophysiology of Colon Flashcards
1
Q
Signs/sx of Ulcerative Colitis vs. Crohn’s Disease
A
- Both UC & Crohn’s:
- Diarrhea
- Weight loss
- fatigue
- UC:
- lower abd pain
- hematochezia (blood in stool)
- mucous in stool
- tenesmus (feeling of incomplete defecation)
- Crohn’s
- mid or lower abd pain
- nausea/vomiting
- fistula sx
2
Q
Macroscopic features: Crohn’s vs. UC
A
- Bowel region
- Crohn’s: Entire GI tract
- UC: Colon
- Fistulae or abscess
- Crohn’s: Yes
- UC: No
- Strictures
- Crohn’s: Common
- UC: No
- Distribution
- Crohn’s: “Skip lesions”
- UC: Diffuse
3
Q
Pathologic/microscopic features: Crohn’s vs. UC
A
- Inflammation
- Crohn’s: Transmural
- UC: Mucosa +/- SM
- Ulcers
- Crohn’s: Deep, linear
- UC: Superficial, confluent
- Fibrosis
- Crohn’s: Marked
- UC: Mild to none
- Granulomas
- Crohn’s: Yes - ~ 20%
- UC: No
4
Q
Other/associated features: Crohn’s vs. UC
A
- Obstruction
- Crohn’s: Yes
- UC: No
- Malabsorption
- Crohn’s: Yes
- UC: No
- Malignant potential
- Crohn’s: With colonic involvement
- UC: Yes
- Recurrence after colectomy
- Crohn’s: Common
- UC: No
- Toxic megacolon
- Crohn’s: No
- UC: Yes
5
Q
Major types of colitis
A
- microscopic colitis
- ischemic colitis
- infectious colitis
- drug-induced colitis
- radiation colitis
6
Q
Characteristics of microscopic colitis
A
- subtypes:
- lymphocytic
- lymph infiltration of mucosa/SM
- collagenous
- thickened collagenous band
- lymphocytic
- mild association w/celiac disease
- good prognosis
7
Q
Characteristics of ischemic colitis
A
- elderly pt.s, often w/out vascular or GI disease
- triggers:
- vasospasm
- dehydration, hypotension, cardiopulmonary insult
- commonly @ “watershed” vascular areas
- splenic flexure
- rectosigmoid
8
Q
Clinical presentation of ischemic colitis
A
- = Abrupt-onset, crampy, lower abdominal pain
- Urgent need to defecate
- Mild diarrhea and/or hematochezia
- Severe diarrhea or bleeding suggests another diagnosis
- Endoscopic findings:
- edema
- ulceration
- +/- bleeding confined to a vascular region
9
Q
Characteristics of infectious colitis
A
- Inflammatory diarrhea +/- hematochezia
- Mucosal invasion
- Toxin-related injury
- Hx:
- short duration
- travel
- ill contacts/exposures
- antibiotic use
10
Q
Exposures ==> infectious colitis
A
- Undercooked beef
- E. Coli
- Contaminated poultry, eggs, milk, lettuce
- Salmonella/Shigella, Campylobacter, Yersinia
- Antibiotic use, hospitalization
- C. Difficile
- Anal intercourse
- Venereal proctitis
11
Q
Characteristics of diverticulosis (general)
A
- outpouchings of colon wall
- composed of mucosa and submucosal layer through muscularis propria
- contain by serosa
- diverticula form and grow
- common in western countries
- low-fiber diet = risk factor
- benign condition in most (80%) of pts
- complications (20-25%)
- infection
- perforation
- abscess formation
- hemorrhage
12
Q
Causes of acute diverticulutis
A
- large stool or food particle lodges @ diverticulum ==> impacted @ diverticulum
- if impaction is not relieved ==> bacteria multiply, expand, form gas ==> rupture of diverticulum
13
Q
Types & sx of acute diverticulutis
A
- uncomplicated
- abscess contained @ colon wall
- complicated
- free perforation
- large abscess
- bowel obstruction
- sigmoid diverticula = most common
- sx:
- LLQ pain
- fever
- nausea/vomiting
14
Q
Characteristics of complications of diverticular disease
A
- large abscess formation
- perforation ==> peritonitis
- diverticular hemorrhage
- mucosa of diverticulum erodes into penetrating vasa recta ==> intraluminal bleeding
15
Q
General characteristics of lower GI bleeding
A
- Bleeding distal to ligament of Treitz
- Colonic bleeding >>> small bowel bleeding
- Usually presents as hematochezia = blood in stool
- Less commonly, melena
