Large Bowel Flashcards
colitis types
bowel wall thickening
infectious, ischemic, pseudomembranous, ulcerative, typhilitis
colonic ischemia
acute arterial thrombus, chronic arterial stenosis, low flow states (CHF), venous thrombosis
splenic flexure most susceptible
rectum has dual blood supply; hardly ever ischemic (superior rectal artery, and inferior/middle rectal rectal arteries)
ischemic colitis findings
segmental, continuous thickening of colon in vascular distribution; sparing of rectum
evaluate for atherosclerotic disease, left atrial thrombus
cause of infectious colitis
bacterial, TB, viral, amoebic
right colon: yersinia, salmonella, colonic TB (and ileocecal valve)
pancolitis: e. coli, CMV, C diff
pericolonic fat stranding, ascites, colonic wall thickening
pseudomembranous colitis
infectious coliits; overgrowth of C diff due to alteration of gut flora
pancolitis; accordion sign and thumbprinting
ulcerative colitis
inflammatory bowel disease; begins in rectum and spreads proximally (NO skip lesions); does not extend more proximally than cecum (backwash ileitis)
associated with PSC, colon cancer, cholangiocarcinoma
extra abdominal manifestations of UC
sacroilitis, iritis, erythema nodosum (tender red subcutaneous nodules), pyoderma gangrenosum (cutaneous ulcers)
imaging findings of UC
circumferential wall thickening with granular mucosal pattern; pseudopolyps
collar butten ulcer
lead pipe colon
toxic megacolon
typhilitis/neutropenic enterocoiltis
right sided colitis in immunocompromised patients
treat with abx and antifungals
polyposis syndromes affecting the bowel
FAP, hereditary nonpolyposis colon cancer syndrome (Lynch), peutz jeghers, cowden syndrome, cronkhite canada
FAP
AD syndrome with innumerable premalignant adenomatous polyps
treatment: prophylactic colectomy
gardner syndrome
variant of FAP
polyps + desmoid tumors + osteomas + papillary thyroid cancer + epidermoid cysts
turcot syndrome
variant of FAP
polyps + CNS tumors (glioma/medulloblastomas)
hereditary nonpolyposis colon cancer/Lynch syndrome
AD polyposis caused by DNA mismatch repair and microsatellite instability on molecular level
adenomatous colon polyps
associated with endometrial, stomach, small bowel, liver, biliary malignancies
cowden syndrome
AD of multiple hamartomatous polyps in skin and external mucous membranes
increased risk of thryoid cancer (follicular), skin, oral, breast, uterine malignancies