Lower GI Flashcards
Describe an operation for Colonic ischemia?
Control contamination Palpation of celiac, SMA, IMA pulses Pattern of ischemia may suggest etiology (complete vs. patchy) Hand-held Doppler Wood’s lamp, warm packs Left colon involvement: resection w/colostomy + mucous fistula or Hartmann’s pouch Right colon involvement: resection with ileostomy and mucous fistula Second look laparotomy
Describe an operation for Acute SB ischemia (embolus)
Prep access to greater saphenous vein in thigh
Expose SMA
confirm SMA embolus palpation, jejunal sparring
Embolectomy through transverse arteriotomy
Heparin post-op
“Second look procedure” within 24 h
Describe an operation for sub-acute SB ischemia (thrombosis)
Prep access to greater saphenous vein in thigh
Expose SMA and perform an embolectomy thru a transverse arteriotomy
Assess flow
If poor, SVG between infrarenal aorta and
SMA
(can use suprarenal aorta and pass graft behind
pancreas to SMA)
Heparin post-op
Resect nonviable segments + “second look procedure”
within 24 h
When do you need to do a cystectomy with colon cancer operation?
Invasion of the trigone
What imaging test to get for colon cancer invading kidney?
Contrast pyelogram to evaluate function of contralateral kidney
What operation for obstructing sigmoid cancer with cecal perforation?
Stable
unstable
stable: subtotal colectomy with primary ileorectal
anastomosis
unstable: ileostomy, cecectomy, mucous fistula if unstable
and then will need second stage to remove tumor
What and when do you order imaging for enterocutaneous fistula?
Get CT with IV and PO contrast at diagnosis to evaluate for abscess/IR drain/ degree of contamination.
Medically stabilize for 1 week (if possible) and repeat imaging as a fistulagram to evaluate for distal obstruction.
What is the formula for TPN?
1 gm/kg/day protein
25 kcal/kg/day CHO
25% glucose, 3–4% amino acids, 10% FFA want
50% of non-protein calories as glucose and 50% as
FFA)
What is staging of Hemorrhoids?
Stages of Internal hemorrhoids (above dentate line and
therefore usually painless)
I Painless rectal bleeding
II Prolapse with defecation, spontaneously reduce
III Prolapse with defecation but reduction only manually
IV Unable to reduce
External hemorrhoids are below the dentate line and
hurt when become thrombosed
Operations for hemorrhoids by stage:
Make sure patient has had a colonoscopy!
acute thrombosis→ elliptical surgical excision
under local anesthesia
Stage I and II internal hemorrhoids→ rubber band ligation
perform banding of only one or two quadrants
No banding if septic concern (prosthetics)
Stage III and IV and recurrent symptomatic external
hemorrhoids treated with Ferguson closed hemorrhoidectomy
(elliptical incision over each hemorrhoid down to
sphincter and closure incorporating some of sphincter
fibers to prevent prolapse)
When do you do a colectomy for a polyp
Can do for any one of the following conditions:
sessile polyp
ambiguous margins
unfavorable histopathology
high grade (3 or 4)
angiolymphatic invasionWhat are non-operative treatments for Ogilvies?
Colonoscopic decompression IV neostigmine (need to be in ICU to monitor for bradycardia)
At what diameter does toxic megacolon start?
6 cm
What is colonoscopic surveilance for UC
First scope 5 years after diagnosis
Then yearly.
When do you consider prophylactic colectomy for UC?
At first evidence of dysplasia.
Usually occurs ~10 years from diagnosis.
What are surgical options for prophylactic colectomy for UC?
- Proctocolectomy with end-ileostomy
- TAC with ileorectal anastomosis (and rectal surveilance)
- Total proctectomy and mucosectomy with IAPP
How do you do a total proctectomy with IAPP?
Preop: bowel prep, antibiotics, sqh, 2u RBC
- Place patient in lithotomy position
- midline incision
- mobilize complete abdominal colon
- Divide the terminal ileum and the colonic mesentery
- Incise the pelvic peritoneum and sharply dissect the TME plane down to the level of the levators.
How do you do a total coloproctectomy with IAPP?
Preop: bowel prep, antibiotics, sqh, 2u RBC
- Place patient in lithotomy position
- Perform a perianal mucosectomy by elevating the mucosal with 1% epinephrine and then resecting in a sleeve like fasion.
- midline incision
- mobilize complete abdominal colon
- Divide the terminal ileum and the colonic mesentery
- Incise the pelvic peritoneum and sharply dissect the TME plane down to the level of the levators.
- Confirm completion of the mucosectomy.
- Pick location for J-pouch to minimize tension.
- Align the antimesenteric border of the TI with vicryl
- Join the lumens of both limbs of the j-pouch with a linear cutting stapler.
- Handsewn pouch to anal anastomosis with interupted 4-0 PDS.
- Leave a pelvic drain and do a diverting ileostomy.
When do you do a total coloproctectomy for FAP?
Around age 25;
would discuss fertility as a risk factor.
Mean age for onset is 40.
Post-op Chemo for Colon Cancer?
All T4 and all stage III gets FOLFOX or FOLFIRI for 6 months.
How do you identify HNPCC/Lynch Syndrome on a path report?
microsatellite instability (MSI) with mutations in DNA mismatch repair genes
What are the most common DNA mismatch repair mutations?
MSH2 and MLH1
What is Amsterdam Criteria for Lynch Syndrome?
- history of colorectal cancer in three generations
- two affected first degree relatives in two successive generations
- at least one presenting prior to age 50
What is colonoscopy surveilance for Lynch syndrome?
every 1-2 years starting at age 25.
