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Flashcards in Fiser Chapter 36 COLORECTAL Deck (130):
1

HNPCC patient gets CRC, what is tx?

Total proctocolectomy with the first cancer operation

50% get metachronous lesions within 10 years, often have multiple primaries

2

UC toxic colitis tx

NG tube, fluids, steroids, bowel rest, abx (cipro/flagyl)

50% need surgery

Avoid barium enemas, narcotics, anti-diarrheals, anti-cholinergics

3

Carcinoid of colon and rectum

Infrequent cause of carcinoid (15%)
Mets related to size of tumor
2/3 of colon carcinoids have either local or systemic spread

Tx: resect
Low rectal < 2 cm: wide local excision with negative margins
Low rectal > 2 cm or invasion of muscular propria: APR
Colon or high rectal: formal resection with adenectomy

4

Effect of radiation on CRC

When combined with chemo: decreases local recurrence and increases survival

5

Colonic obstruction causes

1. Cancer
2. Diverticulitis

6

UC tx

Sulfasalazine or 5-ASA
Loperamide (avoid in toxic colitis)

Acute: steroids, consider cyclosporine or infliximab

7

APR side effects

Impotence and bladder dysfunction from injured pudendal nerves

8

Denonvilliers fascia

Anterior rectovesicular fascia (men) or rectovaginal fascia (women)

9

Pathology shows T2 lesion after transanal excision of rectal polyp, what is tx

APR or LAR

10

CRC main gene mutations

ADK53:

APC, DCC, K-ras, p52

11

Turcot's syndrome

FAP with colon cancer and brain tumors

12

Inferior rectal artery comes off of what?

Internal budendal (off internal iliac)

13

Sigmoid volvulus risk factors

-High-fiber diets (Iran)

-Debilitated psychiatric patients, neurologic dysfunction, laxative abuse

14

Ogilvie's treatment

Correct lytes (especially K), stop drugs that slow gut, NGT
If colon >10 cm (high risk perf) -> decompress with colonoscopy and neostigmine, cecostomy if fails

15

Plicaue semilunares

Transverse bands that form haustra

16

Most common major morbidity after UC surgery with ileoanal anastomosis

Leak most common: drainage and abx
Infectious pouchitis: flagyl

17

Superior rectal artery comes off of what?

IMA

18

N staging for CRC

N: Negative nodes

N1: 1-3 nodes

N2: 4 or more nodes

N3: central nodes positive

19

Indications for surgery in diverticulitis

Total obstruction not resolved with medical therapy, perforation, or abscess formation not amenable to perc drainage, or inability to exclude cancer

-Resect all of sigmoid down to superior rectum

20

Causes of megacolon

Hirschprung's: rectosigmoid most common, dx rectal biopsy

Trypanosoma cruzi: most common acquired cause, secondary to destruction of nerves

21

Azotemia after GI bleed

Caused by production of urea from bacterial action on intraluminal blood (increases BUN, also get increased total bili)

22

Watershed areas

Griffith's (splenic flexure)
Sudeck's (upper rectum where superior and middle rectal arteries join)

23

Amoebic colitis

Entamoeba histolytica from contaminated food and water with feces that contain cysts

Primary: colon
Secondary: liver

Risk factors: Mexico, EtOH

Symptoms: similar to US dysentery; chronic more common form (3-4 BMs/ day, cramping, fever)

Dx: endoscopy -> ulceration, trophozoites, 90% anti-amebic Abs
Tx: Flagyl, diiodohydroxyquin

24

Diverticula

Herniation of mucosa through colon wall at sites where arteries enter muscular wall, circular muscle thickens adjacent to diverticulum with luminal narrowing, present in 35% population

Caused by straining

Most occur on left side in sigmoid colon (80%)
Bleeding more likely with R sided
Diverticulitis more likely with L sided

25

MCC lower GI bleed

Diverticulosis bleeding: caused by disrupted vasa rectum, creating arterial bleeding, usually significant, 75% stops spontaneously, 25% recurs

26

APR indications

Malignant sigmoid or rectal lesions (not benign), that are not amenable to LAR (need at least 2 cm margin (2 cm from levator ani muscles), otherwise need APR)

27

Neutropenic typhlitis

Tx: abx, will improve when WBC increases

Surgery ONLY for free perf (not pneumatosis intestinalis)

28

Stump pouchitis

Diversion or disuse proctitis

Tx: Short-chain fatty acids

29

When is APR or LAR indicated (rather than transanal excision)?

Low rectal T2 or higher

30

UC characteristics

Mucosa and submucosa inflammation

Unusual to have strictures or fistulae

Spares anus: starts in rectum, contiguous

Bleeding, mucosal friability, pseudopolyps and collar button ulcers

Backwash ileitis possible

Crypt abscesses

31

Primary anastomosis in CRC resection

Most Right sided CRC can be primarily anastomosed without ostomy

32

What are features of increased cancer risk in polyps?

> 2 cm

Sessile

Villous

33

Best method of picking up CRC intrahepatic mets

Intraoperative US (3-5 mm resolution, better than CT/MRI/regular US)

34

Rectal vein drainage

Superior and middle into IMV (then PV)

Inferior into internal iliac vein and eventually IVC

35

Lower GI bleed with tufts and slow emptying on angiogram

Angiodysplasia: venous, usually R colon, usually less severe but more likely to recur than diverticular bleeds

20% have AORTIC STENOSIS, and usually gets better after valve replacement

36

Waldeyer's fascia

Posterior rectosacral fascia

37

HNPCC cancer surveillance

Colonoscopy starting at age 25 or 10 years before primary relative go cancer

Also surveillance for other cancer types in family

38

Diverticulitis complications

Abscess: symptoms of obstruction, fluctuant mass, peritoneal signs, fever, wbc >20 -> percutaneous drainage

Colovesicular fistula: fecaluria, pneumouria, colovaginal fistula in women
Dx: cystoscopy best
Tx: Close bladder opening, resect involved colon, reanastomosis, diverting ileostomy, interpose omentum between bladder and colon

39

Crohn's characteristics

Transmural inflammation

Granulomas

Fissures, fibrosis, fistulas, ulcers

Small bowel involvement

Skip lesions

Perianal disease, but rectum may be spared

Cobblestoning with long-standing disease

Fat wrapping

40

CRC chemo drugs

FOLFOX:
-5-FU
-Leucovorin
-Oxaliplatin

41

CRC surveillance after treatment

Colonoscopy at 1 year, mainly to check for new primary (metachronous) colon cancer

42

Most common polyp

Hyperplastic
no cancer risk

43

Cecal volvulus tx

Can try to decompress with colonoscopy but unlikely to succeed (only 20%)

OR for Right hemicolectomy is best, can try cecopexy if colon viable and patient frail

44

What is the most important prognostic factor in CRC

Nodal status

45

UC surgical indications

-Massive hemorrhage
-Refractory toxic megacolon
-Acute fulminant UC, intractability
-Obstruction
-ANY dysplasia, cancer
-Systemic complications
-Failure to thrive
-Long standing disease >10 years
-Prophylaxis against colon CA (controversial)

46

Contraindications for colonoscopy

Recent MI

Splenomegaly

Pregnancy (if fluoroscopy planned)

47

Most common site of primary CRC

Sigmoid

48

CRC liver metastasis 5-year survival?

35% if resectable leaving adequate liver function

49

Pathology shows T1 lesion after transanal excision of rectal polyp, what is tx

Transanal excision adequate if margins clear (2 mm), well differentiated, has no lymphovascular invasion

50

Most common neoplastic polyp

Tubular adenoma, generally pedunculated

51

Intestinal wall layers

-Serosa
-Muscularis propria: circular muscle
-Submucosa
-Mucosa (columnar epithelium): muscularis mucosa is small muscle layer below mucosa above basement membrane

52

Infections causing colitis

-Salmonella
-Shigella
-Campylobacter
-CMV
-Yersinia (fecal-oral, can mimi appendicitis, tx tetracycline or Bactrim)
-Viral
-Giardia

53

Bloody diarrhea, abdominal pain, fever, weight loss

UC

54

Preoperative chemoradiation before APR?

Produces complete response in some patients

Might help preserve sphincter function

-May help shrink rectal tumors, allowing down-staging of the tumor and possibly allowing LAR versus APR

55

LLQ pain, tenderness, fever, leukocytosis

Diverticulitis: mucosal perf with adjacent fecal contamination, denotes infection and inflammation of colonic wall and surrounding tissue

Dx: CT scan only if worried abut complications

Follow-up colonoscopy to r/u cancer

Tx: levofloxacin/flagyl, 3 days bowel rest, outpatient if mild

56

Distal margin in colon resection for diverticulitis

Normal rectum

57

Main nutrient of colonocytes

Short-chain fatty acids

58

Polypectomy shows T1 leasion, what is tx

Polypectomy adequate if margins clear (2 mm), well differentiated, has no lymphovascular invasion

Otherwise need formal resection

59

25yo presents obstructed with dilated cecum in RLQ

Cecal volvulus

60

UC surgery

Total proctocolectomy, bring up ileostomy and connect later if emergent

If elective: Rectal mucosectomy, J-pouch, low rectal ILEOANAL ANASTOMOSIS with temporary diverting ileostomy while pouch heals. Can also perform APR with ileostomy.

61

Risk factors for CRC (colorectal cancer)

Red meat and fats (O2 radicals)

Clostridium septicum association

62

T staging for CRC

T1: into submucosa

T2: into mucularis propria

T3: into serosa (or through MP if no serosa)

T4: into free peritoneal cavity or other organs

63

When do polyps start in FAP?

Puberty

64

Colonic wall plexi

Outer: Auerbach's

Inner: Meissner's

65

MCC of death in FAP following colectomy

Periampullary tumors of the duodenum

66

CRC lung metastasis 5-year survival?

25% in selected patients after resection

67

Middle rectal artery comes off of what?

Internal iliac: during LAR or APR, the lateral stalks contain the middle rectal arteries

68

Cecal mass/abscess with fistula, path shows yellow-white sulfure granules

Actinomyces: suppurative and granulomatous, cecum most common location, can be confused with CA

Tx: PCN, tetracycline, abscess drainage

69

Watery, green, mucoid diarrhea with pain and cramping, occurring 3 weeks after abx

C diff

Tx: PO vanc or flagyl, or IV flagyl, +/- lactobacillus

70

Risk of local recurrence in rectal versus colon cancer

Higher in rectal

71

Key finding in C diff pseudomembranous colitis

PMN inflammation of mucosa and submucosa, pseudomembranes, plaques, ringlike lesions in distal colon

72

Abdominal pain, bright red bleeding, endoscopy shows cyanotic edematous mucosa covered with exudates

Ischemic colitis: low-flow state (recent MI, CHF), ligation of IMA at surgery (AAA repair), embolus or thrombosis of IMA, sepsis

73

Use of rectal US in rectal cancer

Assessing depth of invasion (sphincter involvement), recurrence, presence of enlarged nodes

Need total colonscopy to r/o synchronous lesions

74

Gardner's syndrome

FAP with colon cancer and desmoid tumors/osteomas

75

What is associated with the worst prognosis in CRC?

Mucoepidermoid type

76

APR

Abdominoperineal resection

-Rectum, anal canal excised
-Permanent colostomy placed

77

When is polpectomy enough for invasive carcinoma?

Polypectomy is adequate treatment for invasive carcinoma only if margin is at least 2 mm, not poorly differentiated, and no e/o venous or lymphatic invasion

78

UC extraintestinal manifestations

-Failure to thrive in kids is most common extraintestinal manifestation requiring total colectomy
-PSC (risk continues after colectomy)
-Ankylosing spondylitis (risk continues after colectomy)
-Pyoderma gangrenosum
-HLA B27: sacroiliitis, AS, UC
-Thromboembolism

79

Colon cancer screening options

-Colonoscopy every 10 years, or

-High-sensitivity fecal occult blood test every 3 years and flex sig every 5 years, or

-High-sensitivity fecal occult blood testing annually, or

-Double contrast barium enema or CT colonography every 5 years

80

Surveillance in patients with suspected FAP

Flexible sigmoidoscopy (do NOT need colonoscopy)

Also endoscopy every 2 years to check for duodenal polyps

81

Where are most polyps found?

Left side

82

What is associated with an improved prognosis in CRC?

Lymphocytic penetration

83

Tx of isolated liver or lung mets in CRC?

Resection

84

What layer of colon wall does 80% of blood flow go?

Mucosa and submucosa

85

What marks the transition between the rectum and anal canal?

Levator ani (which then becomes external sphincter)

86

Goals of resection in CRC

En bloc

Adequate margins (2 cm)

Regional adenectomy

87

Infectious pouchitis

Tx: metronidazole

88

Crypts of Liberkuhn

Mucus-secreting goblet cells

89

Amount of bleeding needed for arteriography and tagged RBC scan

Arteriography: at least 0.5 cc/min
Tagged RBC: at least 0.1 cc/min

90

External and internal sphincters

External (puborectalis): continuation of levator ani, voluntary control
Internal pudendal nerve, inferior rectal branch

Internal sphincter: continuation of muscularis propria, smooth muscle, involuntary, normally contracted

91

Most likely polyp to produce symptoms

Villous adenoma, generally sessile and larger

50% have cancer in them

92

Indications for APR

Rectal pain with rectal cancer

93

UC toxic megacolon definition

Toxic colitis plus distension, abdominal pain, tenderness

94

What portions of colon are retroperitoneal?

Ascending, descnending, sigmoid

Peritoneum covers anterior upper 2/3 of rectum

95

What can cause a false-positive quaiac?

Beef

Vitamin C

Iron

Cimetidine

96

IBD perforation location

UC: transverse colon more common

Crohn's: distal ileum most common

97

AXR shows bent inner tube sine, gastrografin enema shows bird's beak sign

Sigmoid volvulus

98

When can you do transanal excision of low rectal cancer rather than APR or LAR?

T1 (limited to submucosa)

< 4 cm

Well differentiated

Negative margins (need 1 cm)

No neurologic or vascular invasion

99

UC cancer risk and screening

In patients with pancolitis, starting 10 years after diagnosis, 1% per year
-Cancer evenly distributed throughout colon
-Need yearly colonoscopy starting 8-10 years after diagnosis

100

Surveillance after UC surgery

Lifetime surveillance of residual rectal area. Many ileoanal anastomoses need resection d/t/ cancer, dysplastic changes, refractory pouchitis, of pouch failure (incontinent)

101

Taenia coli

3 bands that run longitudinally along colon
At rectosigmoid junction become broad and completely encircle bowel

102

CRC disease spread

- Nodes first (nodal status most important prognostic factor)

- Liver via PV (number 1 site of mets)

- Lungs via iliac vein (number 2 site of mets)

-Ovaries

-Spine via Batson's plexus (in RECTAL not colon cancer)

-Adjacent organs

(generally not to bone)

103

Definition of invasive carcinoma

If goes through basement membrane below muscularis mucosa, into submucosa. If just into muscularis mucosa, is intramucosal cancer

104

When is chemo/radiation indicated for CRC?

Colon cancer:
Stage 3 or 4 (positive node or distant mets): postop chemo only

Rectal cancer:
Stage 2 and 3 rectal cancer (T3 or nodes): pre-op chemoradiation
Stage 4: chemo and radiation +/- surgery

105

Diverticulosis bleeding dx and tx

Dx: NG tube to rule out upper GIB, colonoscopy
-If massive with hypotension and tachy: Angio
-If hypotensive and not responding to resusc: OR
-Intermittent bleeds hard to localize: tagged RBC scan

Tx:
-Colonoscopy
-Arteriography with vasopressin or highly selective coild embolization
-Segmental colectomy (or subtotal colectomy if cannot identify site)

106

Colon cancer screening should start at what age?

50 for normal risk

10 years before or at age 40 for intermediate risk (family history)

107

Extensive low rectal villous adenomas with atypia, what is tx

Transanal excision, can try mucosectomy, as much of polyp as possible

NO APR UNLESS CANCER PRESENT

108

FAP treatment

Total colectomy prophylactically at age 20: proctocolectomy, rectal mucosectomy, and ileoanal pouch (J-pouch), or
Total proctocolectomy with end ileostomy

Then lifetime surveillance of residual rectal mucosa

109

Vascular supply of colon

SMA (ileocolic, right and middle colic arteries): ascending and 2/3 transverse colon

IMA (left colic, sigmoid branches, superior rectal): 1/3 transverse, descending colon, sigmoid, upper rectum

Marginal artery: connects SMA to IMA, providing collateral flow, runs along colon margin

Arc of Riolan: short direct connection between SMA and IMA

110

Colon inertia

Slow transit time; may need subtotal colectomy

111

Performing appy and get in there and find out its actually R sided diverticulitis, what is tx

Right hemicolectomy

112

Gangrenous ischemic colitis tx

OR for sigmoid resection or left hemicolectomy

113

Colon electrolytes

Secretes K

Reabsorbs Na and H2O

114

Which nerves are parasympathetic and sympathetic?

Pelvic splanchnics: parasympathetic
Lumbar and scaral plexus: sympathetic

115

M staging for CRC

M1: distant mets
Automatically become stage IV

116

Venous drainage of colon

Follows arterial except IMV, which goes to splenic. Splenic vein joins SMV to form PV behind the pancreas

117

HNPCC (Lynch syndrome) genetics

Autosomal dominant
5% of population

DNA mismatch repair

Predilection for right-sided and multiple cancers

118

Ogilvie's syndrome

Pseudoobstruction, associated with opiates, bedridden or older patients, recent surgery, infection or trauma

Massively dilated colon which can perforate

119

Lymphatic drainage of rectus

Superior and middle into IMA nodal lymphatics

Lower into IMA and internal iliac nodes

120

UC changes on barium enema

Loss of haustra, narrow caliber, short colon, loss of redundancy (avoid in toxic colitis)

121

Sigmoid volvulus tx

Colonoscopy to decompress (80% reduce, 50% will recur)

Sigmoid colectomy during same admission

If gangrene or peritonitis: OR for sigmoidectomy

122

Incidence of CRC recurrence

20%, usually within 1 year

5% get another primary, which is the main reason for surveillance colonoscopy

123

Endoscopic or surgical removal of polyp?

Generally can remove pedunculated polyps endoscopically. If cannot remove whole polyp (more common with sessile), need segmental resection

124

Watershed areas of colon

Splenic flexure (Griffith's point): SMA and IMA junction

Rectum (Sudak's point): Superior rectal and middle rectal junction

Overall, colon is more sensitive to ischemia than small bowel d/t less collaterals

125

Amount of blood needed to see melena

50 cc

126

FAP genetics

APC gene on chromosome 5
Autosomal dominant, all have cancer by age 40

20% are spontaneous

127

Lynch I versus II

Lynch I: just colon CA risk

Lynch II: also risk of ovarian, endometrial, bladder, stomach cancers

128

UC toxic colitis definition

> 6 bloody stools/day, fever, tachy, Hgb drop, leukocytosis

129

Amsterdam criteria for HNPCC

"3, 2, 1"

At least 3 first degree relatives

Over 2 generations

1 with cancer before age 50

130

Radiation damage in CRC

Usually rectal injury
Vasculitis, thrombosis, ulcers, strictures