Lower GI Pathology Flashcards
1
Q
- Hiatal/sliding: cardia of stomach is diplaced into the esophagus
- Paraesophageal: cardia of stomach penetrates weakness in diaphragm into peritoneal space
- intestinal hernia: displacment of segment of bowel into peritoneal space
Complications:
- Reflux
- Impaired venous drainage
- incarceration, strangulation, Infarction
A
Hernia
2
Q
- segment of intestine telescoping into distal segment
- may lead to obstruction, compression of vessels, infarction
- commonly caused by tumor
A
Intussusception
3
Q
- Complete twisting of loop of bowel
- results in luminal and vascular compromise
- commonly in sigmoid colon (elderly) and cecum (young adults)
A
Volvulus
4
Q
- Congenital anganglionic megacolon
- DX requires absence of ganglionic cells within affected region
- defective relaxation and peristalsis of rectum and distal sigmoid colon
- associated with Down syndrome
- Myelnteric/Auerbach plexus: regulates motlity
- Submucosal (Meissner) plexus: regulates blood flow, secretions and absorption
A
Hirschsprung’s Disease
5
Q
- outpouching of all 3 layers of the bowel wall (true diverticulum)
Rule of 2’s:
- presents during 1st 2 years of life
- seen in 2% of population
- within 2 feet of ileocecal valve
- 2 inches long
- 2x more common in males
A
Meckel Diverticulum
6
Q
- Pseudodiverticulum: involve only muscosa, submucosa and muscular is propria (not transmural)
- Acquired: assoc with constipation, straining and low-fiber diet
- arise where vasa recta traverse the muscular is propria
- Generally multiple
- most comon in the sigmoid colon
A
Colonic Diverticula / Diverticulosis
7
Q
- inflammation of the diverticulum due to obstruction of fecal material
- presents with appendicitis-like symptoms in the LLQ (location of sigmoid colon)
- prone to perforation
A
Diverticulitis
8
Q
- Mucosal and submucosal vascular malformations (acquired)
- usually arises in the cecum and right colon due to high wall tension
- Ruptures present as hematochezia (passing blood in stool)
- don’t biopsy, b/c may bleed
A
Angiodysplasia
9
Q
- Distended blood vessels below the anorectal line
A
External Hemorrhoids
10
Q
- Distended blood vessels above the anorectal line, within the distal rectum
A
Internal Hemorrhoids
11
Q
Mucosal: due to acute/chronic hypoperfusion
- e.g., shock, cardiac failure, cocaine use (vasoconstriction), dehydration
Transmural: due to acute vascular obstruction
- Atherosclerosis, aortic aneurysm, embolization
2 phases:
- initial hypoxic injury
- Reperfusion injury (free radical damage)
Complication:
- stricture
- postpandrial pain and weight loss
- bloody diarrhea
A
Ischemic Bowel Disease
12
Q
- intestinal segments at end of their arterial supply
- splenic flexure
- sigmoid colon and rectum
- right colon
A
Watershed zones
13
Q
- inflammation due to obstruction of the appendix by fecalith (fecal material)
Acute inflammation: neutrophilic infiltrate extending into muscularis propria
- Periumbilical pain, migrating to RLQ (McBurney point)
- repture results in peritonitis (rebound tenderness)
A
Appendicitis
14
Q
- autsomal recessive deficiency of apolipoprotein B-48 (make chylomicrons) and B-100 (make VLDL and LDL)
- results in malabsorption
A
Abetalipoproteinemia
15
Q
Systemic tissue damage, characterized by macrophages (Pas+) loaded with Tropheryma whippelii
- involves the small bowel lamina propria (foamy macrophages in the lamina propria)
- causes compression of lacteals, resulting in fat malabsorption and steatorrhea
A
Whipple Disease
16
Q
- immune-mediated damage of small bowel villi (flattening of villi) due to gluten exposure
- Associated with HLA-DQ2 and HLA-DQ8
Presentation:
- flattening of villi; hyperplasia of crypts
- Lymphoplasmacytic expansion of the lamina propria
- abdominal distension, diarrhea, failure to thrive
- Dermatitis herpetiformis
Dx: IgA antibodies; tTG; gliadin
A
Celiac Disease
17
Q
- pathogenic component of gluten
- Once absorbed, is deamindated by tissue transglutaminase (tTG) and is presented to MHC class II cells to Helper T cells
A
Gliadin
18
Q
- diarrhea w/ neutrophils (+- blood) due to mucosal necrosis from C.difficile infection
- overgrowth can occur with use of antibiotics
A
Pseudomembranous Colitis
19
Q
- Chronic relapsing inflammation of the bowel
- diagnosis of excluding: need to rule out infection
A
Inflammatory Bowel Disease
20
Q
- Mucosal & submucosal ulcers
- begins in rectum and extends proximally
- continuous ascending spread
Symptoms:
- Bloody diarrhea
- LLQ pain (rectum)
Histology:
- crypt abscesses with neutrophils
Gross: pseudopolyps; loss of haustra; “lead pipe” sign
Complications:
- Toxic megacolon
- Carcinoma
Association:
- primary sclerosing cholangitis
- p-ANCA positive
Smoking is protective
A
Ulcerative Colitis
21
Q
- Full-thickness inflammation with knife-like fissures
- anywhere from mouth to anus with skip lesions; terminal ileum is most common; rectum is least common
- Gross appearance: Cobblestone pattern with creeping fat and strictures; “string sign” on imaging
Main symptom: RLQ pain with non-bloody diarrhea
Histology:
- lymphoid aggregates with granulomas (non-caseating)
Complications: malabsorption; calcium oxalate nephrolithiasis; fistula formation; carcinoma
Associations: ankylosing spondylitis, sacroiliitis, migratory polyarthritis, erythema nodosum, uveitis
Smoking increases risk
A
Crohn Disease
22
Q
- raised protrusions of colonic mucosa, due to hyperplasia of glands
- classically show a serrated appearance on microscopy
- Benign, with no malignant potential
A
Hyperplastic polyp
23
Q
- autosomal dominant disorder
- Hamartomatous (benign) polyps throughout GI tract, with mucocutaneous hyperpigmentation on lips, oral mucosa and genital skin
- assoc with increased risk of colorectal, breast and gynecologic cancer
A
Peutz-Jeghers Syndrome
24
Q
- sporadic hamartomatous (benign) polyp that arises in children
- characterized by multiple juvenile polyps in stomach and colon
- increased risk of progression to carcinoma
A
Juvenile Polyposis
25
- Autosomal Dominant disorder
- Inherited APC mutation, increasing the propensity to deelop adenmatous polyps throughout the colon and rectum
- requires prophylactic colonectomy; otherwise 100% develop colorectal carcinoma by age 30
Familial Adenomatous Polyposis
26
- FAP with fibromatosis, osteomas and dental abnormalities
Fibromatosis: non-neoplastic proliferation of fibroblasts
Osteoma: benign tumor of bone that usually arises in the skull
Gardner Syndrome
27
- FAP with CNS tumors (meduloblastoma and glial tumors)
Turcot Syndrome
28
- due to inherited mutations in DNA mismatch repair enzymes
- increased risk for colorectal, ovarian and endometrial carcinoma
- Colorectal carcinoma arises de novo (via microsatellite instability); relatively young age, usually right-sided
Hereditary Nonpolyposis colorectal carcinoma (HNPCC)
29
- APC mutations increase risk for formation of polyp
- K-ras mutation leads to formation of polyp
- p53 mutation and increased expression of Cox: progression to carcinoma
Adenoma-carcinoma sequence
30
- annular growth, "napkin-ring" lesion
| - results in obstruction; blood streaked stool
Left-sided carcinoma
31
- Polypoid, raised lesion growth pattern
| - presents with iron defciency anemia and vague pain
Right-sided carcinoma
32
- a neuroendocrine tumor
Carcinoid syndrome: serotonin production
Zollinger-Ellison syndrome: Gastrin producing tumor, increasing risk for PUD
Carcinoid tumor
