Term
| What are the 6 causes of "acute abdomen"? |
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Definition
Intra-abdominal process causing severe pain and often requiring surgical intervention.
1) Inflammatory (Acute appendicitis)
2) Mechanical (Intestinal obstruction)
3) Neoplastic
4) Vascular
5) Traumatic
6) Congenital |
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Term
A patient presents with acute periumbilical pain that has been coming in waves. They have been vomiting as well and are running a high fever.
What is the pathogenesis of this condition? |
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Definition
Sounds like Acute Appendicitis (colicky, peri-umbilical pain and vomiting) with onset of peritoneal inflammation from bacterial infection (fever).
1) Calculi or Fecalith (stone feces) obstructing appendiceal lumen causes acute inflammation and obstruction.
2) Secretions accumulate under pressure behind obstruction and bacterial infection takes place.
3) Following infection, vascular occlusion, gangrene and perforation develop quite quickly.
**Inflammation may extend into surrounding fat and produce periappendicitis!** |
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Term
| What are the gross and histological signs of the disease that causes periumbilical, colicky pain, vomiting and sometimes fever? |
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Definition
Acute appendicitis (fecalith obstruction)
1) Gross
- Swollen, edematous appendix with purulent exudate
2) Histology
- acute inflammation with necrosis and complete destruction of appendiceal wall. |
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Term
| What is the most common location of intussusception and how is it treated? |
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Definition
Ileocecal valve in kids 6 month-2 years of age.
Surgery is curative. |
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Term
| What type if intestinal obstruction is commonly associated with an abnormally long mesentery? |
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Definition
| Volvulus, where bowel twists on itself, causing ischemia |
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Term
What gross/histological features of each infectious colitis described below?
1) Bloody diarrhea, severe cramping abdominal pain, thrombotic, thrombocytic purpura and low-grade fever following consumption of fast-food meat.
2) Diarrhea and abdominal pain following clindamycin administration
3) Child with intense crampy abdominal pain, fever, vomiting, watery diarrhea and dysentery (bloody mucoid) |
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Definition
1) EHEC (O157:H7) Toxin that damages vascular endothelium of kidney and intestine, causing bacillary dysentery and hemorrhagic colitis.
- See epithelial and endothelial ischemia with submucosal edema, hemorrhage and pseudomembranes with PMNs in crypts, LP and pseudomembranes.
2) C. dif
- Grossly, you see Pseudomembranes on endoscopy, with raised mucosal plaques of fibrin, RBCs, PMNs.
- Histologically, mucosal biopsy shows surface glandular drop-out and necrosis.
3) Shigella (invasive, non-motile gram-negative bacillus).
- Grossly, you see friable, ulcerated mucosa with recto-sigmoid inflammation and serpiginous ulcers.
- Histology shows small aphthous ulcers, PMNs, crypt abscess and goblet cell depletion. |
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Term
What gross/histological features of each infectious colitis described below?
1) Watery, bloody diarrhea in immunosuppressed patient
2) Bloody diarrhea and lower abdominal pain
3) Transient diarrhea in children and chronic diarrhea in AIDS patients from contaminated water or fecal-oral |
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Definition
1) CMV
- Cytoplasmic and nuclear viral inclusions present in epithelial and endothelial cells
2) Entameba histolytica (invasive trophozoite)
- Flask-like ulcers
- Trophozoites recognized by their size, nuclear morphology, and phagocytosis of RBC
3) Cryptosporidium (protozoan parasite)
- Adheres to brush-border
- Enveloped by a host membrane |
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Term
A patient presents on antibiotics presents with very variable, cramps, diarrhea, voluminous watery stool, leukocytes in stool (not bloody) peripheral leukocytosis and fever.
On biopsy, you discover pseudomembranes.
What should you look for on stool sample and how do you treat? |
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Definition
| C. dif toxin in stool and stop offending antibiotic |
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Term
| Describe 3 non-infectious causes of colonic diarrhea. |
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Definition
All present with chronic diarrhea and a NORMAL colonoscopy
1) Collagenous colitis
- females with h/x of NSAID use producing watery, non-bloody diarrhea >20 times per day.
- Look for broad, continuos hypocellular, linear, subepithelial fibrous band.
2) Lymphocytic colitis
- chronic water diarrhea with increased intra-eptithleial lymphocytes at luminal surface (>20 per 100 epithelial cells)
3) Amyloidosis
- Beta-amyliod deposition (congo red stain with positive green birefringence.
- Eosinophilic deposits in the submucosal vessels |
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Term
| What are the 3 primary causes of iatrogenic colitis? |
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Definition
UNDERDIAGNOSED.
1) NSAID
- look for intra-epithelial lymphocytes and normal crypt architecture after use of Diclofenac (Voltaren), Naproxen (Naprosyn), Indomethacin (Indocin) or Piroxicam (Feldene).
2) Oral contraceptive
- small bowel thrombosis (especially in left colon at splenic flexure)
3) Melanosis coli
- brown pigmented appearance of colonic mucosa due to habitual anthraquinone laxative use (lipofuscin in macrophages in lamina propria)
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Term
| What is the pathogenesis of diverticular disease? |
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Definition
Acquired pouches of mucosa and submucosa which herniate through the muscular layers of the colon patients who are aging and have diet low in fiber and roughage.
1) Decreased luminal fiber requires increased segmentation, which generates intraluminal pressure and weakens colonic wall.
2) May be asymptomatic. |
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Term
Where are the weak points or "watershed areas" of Ischemic bowel disease?
What are the 3 main causes? |
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Definition
1) Watersheds
- Splenic flexure (Griffith's point)
- Rectosigmoid region (Sudeck's point)
2) Causes
- Vascular occlusion
- non-occlusive ischemia from hypotension in shock and ventricular failure
- mechanical vascular compression. |
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Term
| What are the gross and histological findings associated with ischemic bowel disease? |
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Definition
Can be
- low-grade transient/reversible
- high-grade fuliminant with transmural necrosis
- Chronic persistent/recurrent with fibrosis and stricture.
1) Gross
- Ulceration and pseudomembranes with "thumb-printing" pattern of submucosal edema on barium enema
2) Histology
- Inflammation of SUPERFICIAL mucosa, that ultimately can progress to transmural inflammation. |
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Term
| What histopathological features can help you distinguish between UC and CD? |
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Definition
1) UC will involve distal colon and show DIFFUSE inflammatory infiltrate of mucosa only
- distorted crypt architecture in un-inflamed areas.
- Crypt abscess and cryptitis
2) CD will involve entire colon, with"skip areas" and "cobblestoning," with FOCAL, TRANSMURAL inflammation
- stricture formation, fistula and "bear claw ulcers"
- FOCAL inflammatory infiltrate
- Granuloma |
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Term
| What is fulminent colitis and when does it occur? |
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Definition
In UC, CD and infectious colitis.
- Confluent areas of deep ulceration, often extending into the muscularis
- “Toxic megacolon”- gross dilatation with extreme thinning of the colon wall |
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Term
| What are the major types of colon polyps? |
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Definition
1) Hyperplastic Polyp: Serrated or “sawtooth” lumens
2) Adenomatous Polyp: pedunculated or scissile
- Enlarged, elongated
- Pencil or cigar-shaped
3) Serrated Adenoma
4) Juvenile Polyp: SMAD pathology
5) Peutz-Jeghers Polyp: Pigmented spots on the lip and buccal mucosa |
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Term
| How does the presentation of right and left colon cancer differ? |
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Definition
1) Right will have anemia
2) Left with have changing bowel habits and bleeding |
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