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ABSITE > Fiser Chapter 36 COLORECTAL > Flashcards

Fiser Chapter 36 COLORECTAL Flashcards

1
Q

HNPCC patient gets CRC, what is tx?

A

Total proctocolectomy with the first cancer operation

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

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2
Q

UC toxic colitis tx

A

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

50% need surgery

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

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3
Q

Carcinoid of colon and rectum

A

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

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4
Q

Effect of radiation on CRC

A

When combined with chemo: decreases local recurrence and increases survival

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5
Q

Colonic obstruction causes

A
  1. Cancer

2. Diverticulitis

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6
Q

UC tx

A

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

Acute: steroids, consider cyclosporine or infliximab

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7
Q

APR side effects

A

Impotence and bladder dysfunction from injured pudendal nerves

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8
Q

Denonvilliers fascia

A

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

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9
Q

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

A

APR or LAR

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10
Q

CRC main gene mutations

A

ADK53:

APC, DCC, K-ras, p52

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11
Q

Turcot’s syndrome

A

FAP with colon cancer and brain tumors

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12
Q

Inferior rectal artery comes off of what?

A

Internal budendal (off internal iliac)

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13
Q

Sigmoid volvulus risk factors

A
  • High-fiber diets (Iran)

- Debilitated psychiatric patients, neurologic dysfunction, laxative abuse

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14
Q

Ogilvie’s treatment

A 
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
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15
Q

Plicaue semilunares

A

Transverse bands that form haustra

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16
Q

Most common major morbidity after UC surgery with ileoanal anastomosis

A

Leak most common: drainage and abx

Infectious pouchitis: flagyl

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17
Q

Superior rectal artery comes off of what?

A

IMA

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18
Q

N staging for CRC

A

N: Negative nodes

N1: 1-3 nodes

N2: 4 or more nodes

N3: central nodes positive

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19
Q

Indications for surgery in diverticulitis

A

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

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20
Q

Causes of megacolon

A

Hirschprung’s: rectosigmoid most common, dx rectal biopsy

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

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21
Q

Azotemia after GI bleed

A

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

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22
Q

Watershed areas

A

Griffith’s (splenic flexure)

Sudeck’s (upper rectum where superior and middle rectal arteries join)

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23
Q

Amoebic colitis

A

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

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24
Q

Diverticula

A

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

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25
Q

MCC lower GI bleed

A

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

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26
Q

APR indications

A

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)

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27
Q

Neutropenic typhlitis

A

Tx: abx, will improve when WBC increases

Surgery ONLY for free perf (not pneumatosis intestinalis)

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28
Q

Stump pouchitis

A

Diversion or disuse proctitis

Tx: Short-chain fatty acids

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29
Q

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

A

Low rectal T2 or higher

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30
Q

UC characteristics

A

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

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31
Q

Primary anastomosis in CRC resection

A

Most Right sided CRC can be primarily anastomosed without ostomy

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32
Q

What are features of increased cancer risk in polyps?

A

> 2 cm

Sessile

Villous

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33
Q

Best method of picking up CRC intrahepatic mets

A

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

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34
Q

Rectal vein drainage

A

Superior and middle into IMV (then PV)

Inferior into internal iliac vein and eventually IVC

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35
Q

Lower GI bleed with tufts and slow emptying on angiogram

A

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

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36
Q

Waldeyer’s fascia

A

Posterior rectosacral fascia

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37
Q

HNPCC cancer surveillance

A

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

Also surveillance for other cancer types in family

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38
Q

Diverticulitis complications

A

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

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39
Q

Crohn’s characteristics

A

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

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40
Q

CRC chemo drugs

A

FOLFOX:

  • 5-FU
  • Leucovorin
  • Oxaliplatin
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41
Q

CRC surveillance after treatment

A

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

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42
Q

Most common polyp

A

Hyperplastic

no cancer risk

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43
Q

Cecal volvulus tx

A

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

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44
Q

What is the most important prognostic factor in CRC

A

Nodal status

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45
Q

UC surgical indications

A
  • 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)
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46
Q

Contraindications for colonoscopy

A

Recent MI

Splenomegaly

Pregnancy (if fluoroscopy planned)

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47
Q

Most common site of primary CRC

A

Sigmoid

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48
Q

CRC liver metastasis 5-year survival?

A

35% if resectable leaving adequate liver function

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49
Q

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

A

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

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50
Q

Most common neoplastic polyp

A

Tubular adenoma, generally pedunculated

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51
Q

Intestinal wall layers

A
  • Serosa
  • Muscularis propria: circular muscle
  • Submucosa
  • Mucosa (columnar epithelium): muscularis mucosa is small muscle layer below mucosa above basement membrane
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52
Q

Infections causing colitis

A
  • Salmonella
  • Shigella
  • Campylobacter
  • CMV
  • Yersinia (fecal-oral, can mimi appendicitis, tx tetracycline or Bactrim)
  • Viral
  • Giardia
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53
Q

Bloody diarrhea, abdominal pain, fever, weight loss

A

UC

54
Q

Preoperative chemoradiation before APR?

A

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
Q

LLQ pain, tenderness, fever, leukocytosis

A

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
Q

Distal margin in colon resection for diverticulitis

A

Normal rectum

57
Q

Main nutrient of colonocytes

A

Short-chain fatty acids

58
Q

Polypectomy shows T1 leasion, what is tx

A

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

Otherwise need formal resection

59
Q

25yo presents obstructed with dilated cecum in RLQ

A

Cecal volvulus

60
Q

UC surgery

A

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
Q

Risk factors for CRC (colorectal cancer)

A

Red meat and fats (O2 radicals)

Clostridium septicum association

62
Q

T staging for CRC

A

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
Q

When do polyps start in FAP?

A

Puberty

64
Q

Colonic wall plexi

A

Outer: Auerbach’s

Inner: Meissner’s

65
Q

MCC of death in FAP following colectomy

A

Periampullary tumors of the duodenum

66
Q

CRC lung metastasis 5-year survival?

A

25% in selected patients after resection

67
Q

Middle rectal artery comes off of what?

A

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

68
Q

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

A

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

Tx: PCN, tetracycline, abscess drainage

69
Q

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

A

C diff

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

70
Q

Risk of local recurrence in rectal versus colon cancer

A

Higher in rectal

71
Q

Key finding in C diff pseudomembranous colitis

A

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

72
Q

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

A

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

73
Q

Use of rectal US in rectal cancer

A

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

Need total colonscopy to r/o synchronous lesions

74
Q

Gardner’s syndrome

A

FAP with colon cancer and desmoid tumors/osteomas

75
Q

What is associated with the worst prognosis in CRC?

A

Mucoepidermoid type

76
Q

APR

A

Abdominoperineal resection

  • Rectum, anal canal excised
  • Permanent colostomy placed
77
Q

When is polpectomy enough for invasive carcinoma?

A

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
Q

UC extraintestinal manifestations

A
  • 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
Q

Colon cancer screening options

A
  • 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
Q

Surveillance in patients with suspected FAP

A

Flexible sigmoidoscopy (do NOT need colonoscopy)

Also endoscopy every 2 years to check for duodenal polyps

81
Q

Where are most polyps found?

A

Left side

82
Q

What is associated with an improved prognosis in CRC?

A

Lymphocytic penetration

83
Q

Tx of isolated liver or lung mets in CRC?

A

Resection

84
Q

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

A

Mucosa and submucosa

85
Q

What marks the transition between the rectum and anal canal?

A

Levator ani (which then becomes external sphincter)

86
Q

Goals of resection in CRC

A

En bloc

Adequate margins (2 cm)

Regional adenectomy

87
Q

Infectious pouchitis

A

Tx: metronidazole

88
Q

Crypts of Liberkuhn

A

Mucus-secreting goblet cells

89
Q

Amount of bleeding needed for arteriography and tagged RBC scan

A

Arteriography: at least 0.5 cc/min

Tagged RBC: at least 0.1 cc/min

90
Q

External and internal sphincters

A

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
Q

Most likely polyp to produce symptoms

A

Villous adenoma, generally sessile and larger

50% have cancer in them

92
Q

Indications for APR

A

Rectal pain with rectal cancer

93
Q

UC toxic megacolon definition

A

Toxic colitis plus distension, abdominal pain, tenderness

94
Q

What portions of colon are retroperitoneal?

A

Ascending, descnending, sigmoid

Peritoneum covers anterior upper 2/3 of rectum

95
Q

What can cause a false-positive quaiac?

A

Beef

Vitamin C

Iron

Cimetidine

96
Q

IBD perforation location

A

UC: transverse colon more common

Crohn’s: distal ileum most common

97
Q

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

A

Sigmoid volvulus

98
Q

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

A

T1 (limited to submucosa)

< 4 cm

Well differentiated

Negative margins (need 1 cm)

No neurologic or vascular invasion

99
Q

UC cancer risk and screening

A

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
Q

Surveillance after UC surgery

A

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

101
Q

Taenia coli

A

3 bands that run longitudinally along colon

At rectosigmoid junction become broad and completely encircle bowel

102
Q

CRC disease spread

A
  • 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
Q

Definition of invasive carcinoma

A

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

104
Q

When is chemo/radiation indicated for CRC?

A

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
Q

Diverticulosis bleeding dx and tx

A

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
Q

Colon cancer screening should start at what age?

A

50 for normal risk

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

107
Q

Extensive low rectal villous adenomas with atypia, what is tx

A

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

NO APR UNLESS CANCER PRESENT

108
Q

FAP treatment

A

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
Q

Vascular supply of colon

A

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
Q

Colon inertia

A

Slow transit time; may need subtotal colectomy

111
Q

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

A

Right hemicolectomy

112
Q

Gangrenous ischemic colitis tx

A

OR for sigmoid resection or left hemicolectomy

113
Q

Colon electrolytes

A

Secretes K

Reabsorbs Na and H2O

114
Q

Which nerves are parasympathetic and sympathetic?

A

Pelvic splanchnics: parasympathetic

Lumbar and scaral plexus: sympathetic

115
Q

M staging for CRC

A

M1: distant mets

Automatically become stage IV

116
Q

Venous drainage of colon

A

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

117
Q

HNPCC (Lynch syndrome) genetics

A

Autosomal dominant
5% of population

DNA mismatch repair

Predilection for right-sided and multiple cancers

118
Q

Ogilvie’s syndrome

A

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

Massively dilated colon which can perforate

119
Q

Lymphatic drainage of rectus

A

Superior and middle into IMA nodal lymphatics

Lower into IMA and internal iliac nodes

120
Q

UC changes on barium enema

A

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

121
Q

Sigmoid volvulus tx

A

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

Sigmoid colectomy during same admission

If gangrene or peritonitis: OR for sigmoidectomy

122
Q

Incidence of CRC recurrence

A

20%, usually within 1 year

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

123
Q

Endoscopic or surgical removal of polyp?

A

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

124
Q

Watershed areas of colon

A

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
Q

Amount of blood needed to see melena

A

50 cc

126
Q

FAP genetics

A

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

20% are spontaneous

127
Q

Lynch I versus II

A

Lynch I: just colon CA risk

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

128
Q

UC toxic colitis definition

A

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

129
Q

Amsterdam criteria for HNPCC

A

“3, 2, 1”

At least 3 first degree relatives

Over 2 generations

1 with cancer before age 50

130
Q

Radiation damage in CRC

A

Usually rectal injury

Vasculitis, thrombosis, ulcers, strictures

ABSITE (34 decks)

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