Large Bowel

Question 1

Fuel used by colonocytes? Clinical significance?

Answer 1

short chain fatty acids (eg butyric acid, acetate, propionate) - significant because their use is first line treatment (as rectal enema) for diversion colitis

Question 2

What is the arc of Riolan?

Answer 2

short direct connection between the SMA and the IMA

Question 3

What is Griffith’s point? Sudak’s point?

Answer 3

Griffith’s = splenic flexure (Griffith park = higher) between SMA and IMA; Sudak’s = rectum between superior rectal and middle rectal junction

Question 4

What are Meissner’s and Auerbach’s plexus?

Answer 4

Meissner is inner (M for middle)< Auerbach is outer (sounds like “auter”)

Question 5

What is denovilliers fascia? Waldeyer’s fascia?

Answer 5

Denovilliers fascia is anterior (rectovesicular fascia or rectovaginal), Waldeyer’s is the rectosacral fascia (posterior)

Question 6

Rectal cancer with spinal mets?

Answer 6

Metastasize via Batson’s plexus (venous)

Question 7

Components of FOLFOX

Answer 7

5FU, leucovorin, oxaliplatin

Question 8

Gene for FAP?

Answer 8

APC gene - chromosome 5q - autosomal dominant

Question 9

What is Gardner’s syndrome?

Answer 9

APC gene / colon Ca + desmoid tumors / osteomas

Question 10

What is Turcot’s syndrome?

Answer 10

APC gene / cvolon Ca + brain tumors

Question 11

Gene for HNPCC?

Answer 11

DNA mismatch repair gene, autosomal dominant

Question 12

Amsterdam criteria for Lynch syndrome? Modified Amsterdam criteria?

Answer 12

“3 , 2, 1, 1” = at least 3 relatives with histologically verified cancers of colon, endometrium, small intestine, or pelvi; over 2 generations, 1 with cancer before age 50, 1 should be a first degree relative of the other two – FAP must also be ruled out

Question 13

What are the Hinchey classifications? Definition of complicated diverticulitis?

Answer 13

I confined abscess, II distant/retroperitoneal abscess, III purulent peritonitis, IV feculent peritonitis - complicated diverticulitis includes free perforation, abscess, fistula, obstruction, stricture

Question 14

Stercoral ulcers: locations? Risk factors?

Answer 14

Hard fecaloma leading to local ischemia, ulcer formation and perforation - antimesenteric border of rectosigmoid colon most likely location, associated w/ elderly patients w/ chronic constipation, assoc. w/ NSAIDs and anticholinergic agents

Question 15

Non-surgical treatment for Ogilvie’s syndrome

Answer 15

In stable pt without bowel compromise; bowel rest, NG tube suction, decompressive rectal tube, electrolyte repletion, consider neostigmine (80-90% successful) - contraindications include acute urinary retention, acute coronary artery syndrome, asthma, bronchospasm, 2nd/3rd degree heart block; need to be in cardiac monitoring w/ atropine ready

Question 16

Surgical management of Ogilvie’s syndrome

Answer 16

1) tube colostomy “blow hole”, 2) transanal insertion of long multiperforated drainage tube and 3) total/subtotal colectomy w/ ostomy

Question 17

CRC screening guidelines

Answer 17

Pt w/o IBD/family hx should start at age 50 or presentation w/ worrisome symptoms, w/ FHX begin screening 10 yrs prior to age of dx of any 1st degree relative w/ CRC

Question 18

Ileoanal pouch creation - diarrhea, hematochezia, abdominal pain, fever, malaise; dx, tx

Answer 18

endoscopy w/ biopsy (to r/o Crohns dz), histology, tx w/ cipro (more effective than flagyl), otherwise salicylates, stool enemas, probiotics

Question 19

Screening recommendation for FAP?

Answer 19

1st degree releatives of FAP patients who are APC positive should begin screening at age 10-12 w/ flex sigmoidoscopy, upper endoscopy for surveillance every 1-3 years starting at age 25-30 for periampullary carcinoma

Question 20

Treatment of choice for pt w/ UC and high grade dysplasia seen in the sigmoid colon?

Answer 20

Restorative proctocolectomy with ileal pouch-anal anastomosis

Question 21

Earliest finding of Crohn’s disease on endoscopy?

Answer 21

Mucosal edema -> friable mucosa -> ulcerations

Question 22

Familial juvenile polyposis - genetics, polyp types, risk of colon ca, surveillance, surg mgmt

Answer 22

autosomal dominant (similar to HNPCC, FAP, Peutz-Jegher), polyps are hamartomas (not adenomas) however can degenerate into adenomas and malignancy; lifetime risk of colon ca is 10-38%; colonoscopic surveillance recommended beginning at age 10-12; do polypectomy, if adenomatous changes, than proceed with colectomy

Question 23

Treatment of C. diff infection? Recurrent C. diff infection?

Answer 23

oral metronidazole for 10-14 days - 1st recurrence treated with repeat 10-14 day course, 2nd recurrence treated with oral vancomycin

Question 24

tympanic mass LUQ, XR showed dilated loop of bowel with haustral markings from RLQ to LUQ - dx (types), tx?

Answer 24

cecal volvulus; occurs in younger pts, axial ileocolic volvulus (90% cecum rotates up and over to the LUQ), cecal bascule (10% cecum flips upwards/anterior in a horizontal plane) - tx w/ R hemicolectomy w/ primary anastomosis (vs ostomy if evidence of gangrenous colon); high recurrence rates w/ detorsion/cecopexy, unable to be tx w/ endoscopy

Question 25

40M w/ 5 day of RLQ pain, anorexia and fever, focally tender in RLQ with palpable mass - tx?

Answer 25

acute appendicitis, palpable mass suggests perforation/walled off abscess -> best managed with non-op therapy IV abx/bowel rest (DeVirgilio)

Question 26

Management of iatrogenic and symptomatic colon perforation?

Answer 26

Primary repair – resection and colostomy reserved for pt w/ long standing perforation and diffuse fecal contamination

Question 27

role of chemotherapy in colon cancer? stage 1? 2? 3? 4?

Answer 27

stage 1 (node negative, invades submucosa) colon ca does not need chemo, stage 2 (node negative, invades subserosa or invasion of adj organ) remains debatable, stage 3 combo of 5 FU and leucovorin prolongs survival in stage 3 (+lymph nodes, no distant mets) but not stage 4

Question 28

Pt w/ positive APC gene, sigmoidoscopy shows 8 adenomatous polyps, management?

Answer 28

total proctocolectomy - ideally w/ ileal pouch anal anastamosis - total abdominal colectomy w/ ileorectal anastomosis is another option, requires lifelong surveillance of rectum – ileostomy last option

Question 29

Most common perianal lesion in Crohn’s disease?

Answer 29

Skin tag > fissures. Also higher risk for hemorrhoids, perianal abscess/fistula

Question 30

Explain periumbilical / RLQ pain in appendicitis

Answer 30

Distention of appendix stretches surrounding visceral peritoneum, stimulating its afferent fibers leading to the dull periumbilical pain that later becomes RLQ pain as the localized somatic fibers of the parietal peritoneum are stimulated

Question 31

Most common cause of rectovaginal fistula?

Answer 31

Obstetric injury > Crohn’s

Question 32

Immune function of the appendix?

Answer 32

Secretes IgA

Question 33

What is an Amyand hernia?

Answer 33

Hernia containing an appendix

Question 34

35M w/ 1 day of anorexia, RLQ pain, tenderness and low grade fever. At surgery appendix is normal, cecum and TI are red and inflamed. Management?

Answer 34

Crohn’s terminal ileitis -> close, schedule for colonoscopy. No appendectomy given inflamed cecum, otherwise appendectomy to avoid confusion in future

Question 35

Appendicitis in HIV pt - incidence? Presentation? Labs? Risk of perforation? Morbidity?

Answer 35

Higher incidence compared to regular population, can have atypical symptoms, may not have absolute leukocytosis (but have a relative leukocytosis), higher risk of perforation, similar morbidity in non-perforated cases, higher risk in perforated cases

Question 36

most common worldwide intestinal parasite associated with appendicitis?

Answer 36

ascaris lumbricoides

Question 37

strongyloides stercoralis is associated with…

Answer 37

pneumonitis, malabsorption, bleeding ulcers

Question 38

clonorchis sinesis is associated with…

Answer 38

pigmented gallstones and cholangiocarcinoma

Question 39

acute mesenteric adenitis: bacterial associations, lab/imaging findings vs appendicitis

Answer 39

assoc. with yersinia enterocolitica, helicobacter jejuni, campylobacter jejuni, salmonella/shigella, strep infections of pharynx, more common in children, often preceded by URI – exam is more vague/diffuse tenderness w/o guarding, no localized tenderness; leukocytosis similar (10-15), CT shows generalized lymphadenopathy in the small bowel mesentery

Question 40

most common cause of pseudomyxoma peritonei?

Answer 40

benign mucinous cystadenoma

Question 41

surgical management of appendiceal carcinoid?

Answer 41

tumors >2 cm at the tip or >1 cm with extension into mesoappendix or base proceed w/ right colectomy

Question 42

Screening recommendation for HNPCC?

Answer 42

colonoscopy starting at age 25 (or 10 yrs less than age of family member w/ CRC) - more commonly R sided

Question 43

Where is the majority of water reabsorbed in the body? How does the colon reabsorb water?

Answer 43

Small bowel (more than colon), sodium reabsorbed actively via NaK-ATPase with water following passively, chloride actively absorbed via chloride-bicarb exchange

Question 44

T N M staging for colorectal cancer?

Answer 44

T1 submucosa, T2 muscularis propria, T3 serosa/through muscularis propia, T4 through serosa or into adjacent organs/structure; N1 1-3 nodes, N2 >4 nodes, N3 central nodes positive, M1 distant mets