36 - Colorectal Flashcards

1
Q

Colon secretes _ and absorbs _

A

Secretes - K

Absorbs - water and Na

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2
Q

Layers of colon

A

Mucosa, submucosa, muscularis propria, serosa

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3
Q

Small interwoven inner muscle layer below mucosa but above basement membrane in colon

A

Muscularis mucosa

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4
Q

Portions of colon that are retroperitoneal

A

Ascending, descending and sigmoid

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5
Q

Peritoneum cover this portion of rectum

A

Anterior upper and middle 1/3

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6
Q

Transverse bands forming haustra

A

Plicae semilunaris

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7
Q

3 bands running longitudinally along the colon

A

Taenia coli

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8
Q

Distance of dentate line from anal verge

A

2cm

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9
Q

SMA supplies which portions of the colon (name branches)

A

Ascending - ileocolic, right colic

2/3 Transverse - middle colic

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10
Q

IMA supplies which portions of the colon/rectum (name branches)

A

1/3 Transverse - left colic
Descending - left colic
Sigmoid - sigmoidal branches
Upper rectum - superior rectal

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11
Q

Collateral flow connecting SMA and IMA

A

Marginal artery

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12
Q

Short direct connection between SMA and IMA

A

Arc of Riolan

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13
Q

Superior, middle and inferior rectal artery branches from

A

Superior - IMA
Middle - Internal iliac
Inferior Internal pudendal (branch of internal iliac)

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14
Q

Watershed areas of colon and there junctions

A
Splenic flexure (Griffith's point) - SMA and IMA junction
Rectum (Sudaks point) - superior and middle rectal junction
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15
Q

Anal sphincter with voluntary control

A

External sphincter

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16
Q

Anal sphincter with involuntary control

A

Internal sphincter

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17
Q

External anal sphincter innervation and muscle (type)

A
Inferior rectal nerve (internal pudendal nerve branch)
Levator ani (skeletal)
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18
Q

Internal anal sphincter innervation and muscle (type)

A
Pelvic splanchnic nerves
Muscularis propria (smooth)
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19
Q

The inner and outer nerve plexus of the colon, respectively

A

Inner - Meissner’s plexus

Outer - Auerbach’s plexus

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20
Q

What forms the anal verge

A

0-5cm anal canal, 5-15cm rectum, 15-18cm rectosigmoid junction

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21
Q

Mucin secreting goblet cells of colon

A

Crypts of Lieberkuhn

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22
Q

Slow transit time of the colon

A

colonic inertia

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23
Q

Main nutrient of colonocytes

A

Short chain fatty acids

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24
Q

Tx for stump/diversion pouchitis of colon

A

Short chain fatty acid enema

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25
Q

Tx for infectious pouchitis

A

Metronidazole

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26
Q

Anterior colorectal fascia (rectovesicular/rectoprostatic - men; rectovaginal - women)

A

Denonvilliers fascia

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27
Q

Posterior colorectal fascia (rectosacral)

A

Waldeyer’s fascia

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28
Q

Most common colon polyp

A

Hyperplastic polyp

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29
Q

Most common neoplastic intestinal polyp

A

Tubular adenoma

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30
Q

Most likely to produce sxs, more often cancerous (50%0

A

Villous adenoma

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31
Q

Indications for increased cancer risk of intestinal polyps (3)

A

> 2cm, sessile, villous

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32
Q

Screening age for colon cancer, normal risk and family hx

A
Normal risk - 50yo
Intermediate risk (fam hx) - 40yo or 10 yrs before youngest fam member
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33
Q

Screening options for colon cancer

A
  1. Colonoscopy q10 yrs
  2. Fecal occult blood testing (FOBT) q3yrs AND flex sigmoidoscopy q 5yrs
  3. FOBT annually
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34
Q

Definition of invasive cancer (T1) lesion in colorectal

A

Invasion INTO submucosa (past basement membrane)

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35
Q

Indications for adequate resection with polypectomy of T1 lesion (3)

A

Negative margins (2mm)
Well differentiated
No lymphovascular invasion

36
Q

Low rectal villous adenoma with atypia tx with T1 vs T2 rectal lesion

A

T1 - transanal excision (2mm margins, no lymph/vasc invasion, well diff)
T2 - APR/LAR

37
Q

2nd leading cause of Ca death

A

Colorectal cancer

38
Q

Gene mutations for colon cancer (4)

A

APC
p53
DCC
k-ras

39
Q

Most common site of colon cancer primary

A

Sigmoid

40
Q

Most important prognostic factor colon cancer

A

Nodal status

41
Q

Most common sites of colon cancer metastasis (1 & 2)

A

1 - Liver

2 - Lung

42
Q

Colon cancer metastasizes to liver via _, and lung via _

A

Liver via portal vein

Lung via iliac vein

43
Q

5yr survival rate of colon cancer with liver metastasis and lung metastasis, respectively

A

35% - liver

25% - lung

44
Q

Rectal cancer can metastasize to spine via

A

Batson’s plexus

45
Q

Worst prognosis colorectal cancer

A

Mucoepidermoid

46
Q

Best test for T and N status; assessing depth of invasion

A

Transrectal ultrasound

47
Q

Margins for colorectal cancer resection

A

2cm

48
Q

Best method for picking up intrahepatic metastasis

A

Intraoperative ultrasound

49
Q

Indication for APR vs LAR

A

Need 2cm margin from levator ani muscles for LAR, otherwise need APR

50
Q

T staging for colorectal cancer

A

1 - into submucosa
2 - into muscularis propria
3 - into subserosa or through muscularis propria
4 - through serosa, into adjacent organs/peritoneal space

51
Q

N staging for colorectal cancer

A

0 - nodes negative
1 - 1-3 regional nodes
2 - >/= 4 regional nodes
3 - central nodes

52
Q

Chemo regimen for colorectal cancer

A

FOLFOX (5FU, Leucovorin (folic acid), Oxaliplatin

53
Q

Colon cancer stage getting postop chemo

A

Stage 3-4 (no XRT in colon)

54
Q

Rectal cancer stage getting neoadjuvant chemo-XRT

A

Stage 2-3

55
Q

Rectal cancer stage getting chemo-XRT, +/- surgery

A

Stage 4 (avoid APR with pts with mets)

56
Q

Most common site of damage from XRT

A

Rectum

57
Q

Rate of recurrence of rectal cancer within first yr

A

20%

58
Q

FAP inheritance and gene mutation (+ chromosome)

A

Autosomal dominant; APC gene (chromosome 5)

59
Q

Age for total colectomy (prophylactically)

A

20yo

60
Q

Surgical procedure for FAP

A

Proctocolectomy, rectal mucosectomy, ileoanal pouch

Alternate is total proctocolectomy with end ileostomy

61
Q

MCC death in FAP after colectomy

A

Duodenal tumors (periampullary)

62
Q

Gardner’s syndrome

A

Colon ca + intra-abd desmoid tumors

63
Q

Turcot’s syndrome

A

Colon ca + brain tumors

64
Q

Inheritance and gene with Lynch syndrome (HNPCC)

A

Autosomal dominant; DNA mismatch repair gene

65
Q

Lynch 1 vs lynch 2 risks

A

1 - just colon cancer risk

2 - also at risk for ovarian, endometrial, bladder, stomach

66
Q

Amsterdam criteria for Lynch syndrome

A

3, 2, 1

  • 3 first degree relatives
  • over 2 generations
  • 1 person w/ cancer before 50yo
67
Q

Surveillance colonoscopy time-frame for lynch syndrome

A

25yo or 10 yrs before primary relative

68
Q

Tx for sigmoid volvulus

A

Colonoscopic decompression -> bowel prep/rectal tube -> sigmoidectomy same admission

69
Q

Tx for cecal volvulus

A

Right hemicolectomy

70
Q

Tx for maintenance vs acute UC

A

acute - steroids

maintenance - 5-ASA (mesalazine)/sulfasalazinea and loperamide

71
Q

Most common site of perforation for UC

A

Transverse colon

72
Q

Most common site of perforation for Crohn’s

A

Distal ileum

73
Q

Cancer risk for UC pts with pancolitis

A

1% per yr starting 10yrs after initial dx with pancolotis

74
Q

Most common extraintestinal manifestation of UC requiring total colectomy

A

Failure to thrive in children

75
Q

Which conditions (2) do NOT improve with colectomy in UC

A

Primary sclerosing cholangitis, ankylosing spondilitis

76
Q

Which conditions (3-4) improve with colectomy in UC

A

Ocular problems, arthritis and anemia/(50% pyoderma gangranosum)

77
Q

HLA B27 associated with

A

UC, ankylosing spondylitis, sacroiliitis

78
Q

Tx for pyoderma gangrenosum

A

Steroids

79
Q

Most common location of colon perf 2/2 obstruction

A

cecum

80
Q

MCC of colonic obstruction 1 & 2

A

1 - cancer

2 - diverticulitis

81
Q

Tx for amoebic colitis

A

Flagyl

82
Q

Yellow-white sulfur granule pathology of colonic mass/abscess; tx

A

Actinomyces; tx - penicillin

83
Q

Most common presentation of right sided and left sided diverticula, respectively

A

Right - Bleeding

Left - Diverticulitis

84
Q

Bleeding amount for arteriography to pick up in GI bleed

A

> /= 0.5cc/min

85
Q

Bleeding amount for tagged RBC scan to pick up in GI bleed

A

> /= 0.1cc/min

86
Q

Best dx test for colovesicular fistula

A

cystoscopy