Colorectal Flashcards
1
Q
How long is the rectum?
A
15cm
2
Q
How long is the colon?
A
5-6 feet
3
Q
What is considered an abnormal diameter of the cecum?
A
greater than 9 cm
4
Q
What is the blood supply to the colon?
A
- SMA gives off the ileocolic, right colic, and middle colic arteries
- IMA gives off the left colic, sigmoid branches, and superior rectal arteries
- the marginal and arc of Riolan are collaterals
5
Q
What are the marginal artery and the Arc of Riolan?
A
- the marginal artery is found along the colon wall and connects the SMA and IMA
- the Arc of Riolan is the meandering mesenteric artery and provide a smaller connection between the SMA and IMA via the middle colic and left colic
6
Q
What are the watershed areas of the colon?
A
- the splenic flexure (Griffith’s point) between the SMA and IMA
- the rectosigmoid junction (Sudeck’s point) between the superior and middle rectal arteries
7
Q
What is the arterial blood supply to the rectum?
A
- the superior rectal off the IMA
- the middle rectal off the internal iliac
- the inferior rectal off the internal pudendal
8
Q
What is the venous drainage of the rectum?
A
- the superior rectal to the IMV and the portal venous system
- the middle and inferior rectals to the internal iliac vein and systemic venous system
9
Q
What defines the anal canal?
A
- it begins at the puborectalis sling
- it ends at the anal verge where squamous mucosa blends into perianal skin
10
Q
What is the appropriate resection for the following tumor sites:
- hepatic flexure
- splenic flexure
- transverse colon
- cecum
- left colon
- sigmoid
A
- hepatic flexure: extended right
- splenic flexure: extended left
- transverse colon: transverse
- cecum: right
- left colon: left
- sigmoid: sigmoid
11
Q
Where are most anal fissures found?
A
90% are in the posterior midline
12
Q
What is the non-operative treatment of anal fissures?
A
- psyllium fiber or other bulking agents
- sitz baths
- topical anesthetics
- topical nitrates
- topical calcium channel blockers (as effective as nitrates without the headaches)
- botulinum toxin
13
Q
What are the surgical options for anal fissures? How do they compare?
A
- lateral internal sphincterotomy
- anocutaneous flap (inferior healing rates but lower incidence of incontinence, can be done in additional to LIS)
14
Q
For a patient with anal fissures, what would be contraindications to lateral internal sphincterotomy?
A
- incontinence with botox injection
- women of childbearing age
- prior obstetric injuries
- IBD
- history of sphincter dysfunction/incontinence
15
Q
Describe the management of anal fissures.
A
- start with non-operative treatments including bulking agents (fiber), sitz baths, topical anesthetics, and calcium channel blockers
- nitrates are an alternative to CCBs but typically equal success and more side effects
- next step up would be botox injections
- if patient’s fail these medical therapies, then lateral internal sphincterotomy or anocutaneous flap are possible surgical options
- LIS has a higher healing rate but greater risk of incontinence and is contraindicated for women of childbearing age or that have a history of sphincter dysfunction/incontinence
16
Q
Where are the following anorectal abscess found?
- intersphincteric
- ischiorectal
- perirectal
- supralevator
- submucosal
- deep post-anal space
A
- intersphincteric: between the internal and external sphincter muscles
- ischiorectal: lateral to the rectal wall in the space next to the ischial tubercle
- perirectal: around the anus
- supralevator: above the elevator muscle
- submucosal: under the mucosa of the anal canal
- deep post-anal space: bilaterally ends in the ischiorectal fossa between the anococcygeal ligament and the levator muscle
17
Q
How are anorectal abscess managed?
A
- primary treatment is drainage
- perianal and ischiorectal can be drained via an external incision while deeper intersphincteric and supralevator are done via internal transanal drainage
- those who are immunosuppressed, have cellulitis, or have systemic signs of infection require antibiotics after drainage
18
Q
Which patients with anorectal abscess require antibiotics after drainage?
A
- immunocompromised
- systemic signs of infection
- accompanying cellulitis
19
Q
What is the rate of fistula formation in patients with an anal abscess?
A
33%
20
Q
What is Goodsall’s rule?
A
- helps track anal fistulas
- anterior external openings less than 3 cm from the anal verge take a direct line to the anal canal
- posterior external openings and those more than 3cm from the anal verge take a curvilinear rout to the posterior midline
21
Q
What is the most common type of anal fistula?
A
intersphincteric
22
Q
What is the difference between a high and a low trans-sphincteric anal fistula?
A
- high involve more than ⅓ of the muscle complex
- low involve less than ⅓ of the muscle complex
23
Q
What is the difference between a suprasphincteric and an extrasphincteric anal fistula?
A
- suprasphincteric are lower, they run between the muscles and up and over the external sphincter
- extrasphincteric are higher and run over and above the whole sphincter complex
24
Q
What is the goal of seton placement for fistula-in-ano?
A
generate fibrosis of the tract and convert a high fistula to a low fistula, preparing the tract for later procedures
25
Which anal fistulas can be treated with fistulotomy?
those that involve less than 25% of the sphincter complex
26
What are management options for fistula-in-ano?
- fistulotomy for those involving < 25% of the sphincter complex
- seton placement followed by subsequent LIFT or anorectal advancement flap
27
What separates internal and external hemorrhoids?
whether they are above or below the dentate line
28
How are internal hemorrhoids classified
by extend of protrusion
- I: internal only
- II: spontaneously reduce
- III: require manual reduction
- IV: non-reducible
29
What are the options for conservative management of hemorrhoids?
- reduce time sitting on the toilet
- high fiber intake (25-35g/day)
- high fluid intake/hydration
30
When can thrombosed external hemorrhoids be treated surgically?
within 72hrs of symptom onset
31
What defines complicated diverticulitis?
perforation, abscess formation, fistula formation, stricture, or obstruction
32
Which patients with diverticulitis require admission?
- those that can't tolerate oral hydration
- those that are unreliable
- those with complicated disease (perforation, abscess formation, fistula formation, stenosis, obstruction)
- hemodynamic instability or diffuse peritonitis
33
What are the surgical options for sigmoid diverticulitis?
- resection with primary anastomosis
- resection with Hartmann's
- resection with DLI
34
What size abscess is usually amenable to percutaneous drainage?
those greater than 3cm in diameter
35
What is the proper management of a patient with diverticulitis complicated by a large abscess that is not accessible by IR and not resolving with antibiotics?
can consider laparoscopic washout and drain placement
36
What is the typical course for patients with recurrent diverticulitis?
the first episode is often the worst and multiple uncomplicated episodes does not necessarily increase the risk of needing an emergent colectomy
37
Which patients should be offered elective sigmoidectomy for diverticulitis?
- those who recover from an episode of complicated disease
| - those for whom recurrent disease has a significant impact on their lifestyle
38
What kind of bacteria is C. difficile?
an anaerobic, gram positive bacilus
39
What is the medical management of C. diff?
- first line is oral vancomycin followed by fidaxomicin
| - can also add vancomycin enemas
40
When should you operate for C. diff?
- obvious signs like perforation or peritonitis
- but high mortality when you've gotten to sepsis or perf
- consider early operative intervention for patients requiring pressors or with signs of impending sepsis
41
What is the operative procedure of choice for C. Diff? What's the alternative?
- prefer subtotal colectomy with ileostomy
| - second option is DLI with colonic lavage and anterograde vanc enemas
42
What is the workup for suspected colonic volvulus?
- AXR is usually first indicator
| - next step is contrasted CT to evaluate colonic viability
43
How is sigmoid volvulus treated?
- endoscopic detorsion with decompression tube for 1-3 days
- consider open sigmoid colectomy during index admission
- if emergent surgery is required, perform a Hartmann's
44
How is cecal volvulus treated?
- endoscopic reduction isn't really an option
- patient's require surgery with resection versus pexy
- resection is safer
45
What are the risk factors for perforation in someone with Ogilvie's?
cecum > 12cm or duration > 6 days
46
What is the initial treatment of Ogilvie's?
- if no signs of ischemia and cecum < 12cm, can trial supportive care
- minimize narcotics and anticholinergics
- fluid resuscitate and correct electrolyte abnormalities
- bowel rest and decompression
- trial of neostigmine
47
How does neostigmine serve as a motility agent? What is the most common side effect?
- works as an acetylcholinesterase inhibitor to promote colonic motility
- most common side effect is bradycardia
48
Options for treatment of Ogilvie's
- supportive care
- trial of neostigmine
- endoscopic decompression
- OR for resection
49
What are the operative indications and options for those with Ogilvie's?
- indicated for ischemia or perforation
| - options are resection with ostomy versus anastomosis
50
What is an Altemeier procedure?
- a perineal proctosigmoidectomy, used to treat rectal prolapse in poor surgical candidates
- start with circumferential incision of rectum proximal to dentate line
- deliver and resect the redundant colon
- create a colo-anal anastomosis
51
What is the preferred transabdominal repair for those with rectal prolapse?
- laparoscopic rectopexy
| - add LAR or sigmoid resection for those with constipation
52
What is the main nutrient of colonocytes? What is the main nutrient for enterocytes?
- colon: a short chain fatty acid called butyrate
| - small bowel: glutamine
53
What should you worry about if a patient has a lateral fissure or multiple anal fissures?
Crohn's, HIV, syphilis, TB
54
You take a septic patient with fulminant C. diff colitis to the OR for total abdominal colectomy but upon opening find that the colon appears normal. Next step?
proceed with surgery since it is a mucosal disease and not visible via the abdomen
55
What percentage of patients with UC ultimately require an operation?
15-30%
56
Crypt abscess and pseudo polyps are characteristic findings for what type of IBD?
ulcerative colitis
57
What is the medical management of UC?
- steroids for flares
- mesalamine for maintenance
- infliximab for recalcitrant disease
58
What is considered medically unresponsive UC?
- growth failure in children
- disease progression while on therapy
- poor quality of life despite maximal medical therapy
- desire to avoid lifelong medical therapy (steroids)
- disabiling extra-intestinal manifestations that respond to colectomy (e.g. erythema nodosum, episcleritis, large joint arthropathy)
59
What are the indications for surgery in patients with UC?
- medical intractability
- malignancy
- complications of colitis (stricture, perforation, fulminant colitis)
60
Which extra-intestinal manifestations of UC don't typically respond to colectomy? Which do?
- hepatobiliary manifestations such as PSC typically don't
| - arthropathy, erythema nodosum, and episcleritis do
61
What is the surgery that should be offered to those with UC who are found to have malignancy or high grade dysplasia?
total proctocolectomy with or without IPAA
62
What are the recommended colonoscopy screening guidelines for those with UC?
- start screening endoscopies after 8 years of extensive disease (proximal to splenic flexure)
- then every 1-2 years
- with 4 quadrant biopsies at 10cm intervals throughout the involved colon
63
What surgical reconstruction option is available to those with UC but not Crohn's?
ileal pouch anal anastomosis
64
If a patient with UC has uninvolved rectum, what surgery can you offer them and what surveillance must be performed after?
can offer a total colectomy with ileorectal anastomosis but need annual surveillance of the residual rectal cuff
65
What is the preferred surgical option for patients with UC who must undergo an emergent operation?
total or subtotal abdominal colectomy with end ileostomy
66
Creeping fat is a characteristic of which form of IBD?
Crohns
67
What are the extra-intestinal manifestation of Crohn's?
- arthritis and arthralgias
- megaloblastic anemia
- uveitis
- erythema nodosum
68
What is the medical treatment of Crohn's?
same as UC
- steroids for flares
- mesalamine/5-ASA for maintenance
- infliximab for recalcitrant disease
69
How do the surgical indications for UC differ than those for Crohn's?
- surgery is not curative in Crohn's like it is for UC
- therefore, for Crohn's, it's only used to treat complicated disease (stricture, obstruction, malignancy, perf, fistula)
70
How are Crohn's strictures treated surgically?
- goal is to preserve as much small bowel as possible since they are likely to need multiple resections over time
- short, isolated segments can be resected
- short strictures < 10cm: Heineke-Mikulicz stricturoplasty
- medium strictures 10-20cm: Finney stricturoplasty
- long strictures > 20cm: Michelassi stricturoplasty
71
Describe the following stricturoplasties:
- Heineke-Mikulicz
- Finney
- Michelassi
- HM: longitudinal incision, transverse closure
- Finney: fold strictures segment on itself and make a common channel in the loop
- Michelassi: side-to-side iso-peristaltic anastomosis with overlap of the stenosed segment
72
What are contraindications to stricturoplasty for patients with Crohn's stricture?
- malignancy
- perforation/fistula
- malnutrition
73
What are screening colonoscopy recommendations for the following groups:
1) average risk
2) primary relative with cancer < 60 years old
3) primary relative with cancer > 60 years old
4) one second degree relative with cancer
5) two second degree relatives with cancer
6) those with FAP
7) those with Lynch syndrome
1) colonoscopy every 10 years or sigmoidoscopy with FOBT every 5 years, starting at 50 years old
2) colonoscopy every 5 years at 40 or 10 years before
3) colonoscopy every 10 years at age 40
4) colonoscopy every 10 years at age 50
5) colonoscopy every 10 years at age 40
6) annual sigmoidoscopy starting at 10-12 years old
7) annual colonoscopy starting at 20-25 or 10 years before the youngest affected relative
74
What is the recommended surveillance with the following found on colonoscopy:
a) 1-2 tubular adenomas
b) 3-10 adenomas
c) > 10 adenomas
d) advanced adenomas (villous, >1cm, high grade dysp)
e) hyperplastic polyps < 1cm
a) repeat in 7 years
b) repeat in 3-5 years
c) repeat in 1 year
d) repeat in 3 years
e) repeat in 10 years
75
What are considered advanced adenomas on colonoscopy screening? What is the surveillance colonoscopy recommendation for these?
- size greater than 1cm
- high grade dysplasia
- villous histology
- repeat in 3 years
76
Which malignant polyps can be removed endoscopically?
sessile/pedunculated polyps that can be removed in one piece with negative margins, that are well or moderately differentiated without angiolymphatic invasion, and that are limited to 2mm of invasion past the muscularis mucosa
77
Describe TNM staging for colon cancer.
- T1: invades submucosa
- T2: invades muscularis propria
- T3: invades into pericolonic tissue
- T4a: invades serosa
- T4b: invades surrounding structures
- N1: 1-3 nodes
- N2a: 4-6 nodes
- N2b: 7+ nodes
- M1: distant mets
- stage I: T1-T2, N0, M0
- stage II: T3-T4, N0, M0
- stage III: nodal involvement
- stage IV: distant mets
78
For colon cancer how is positive lymph node involvement defined?
as a 0.2mm deposit of cancer cells or larger
79
What is considered an appropriate oncologic resection for colon cancer?
- need a 5-7 cm proximal and distal margin
| - need at least 12 nodes
80
Which patients with stage IV cancer are considered resectable?
medically fit patients with isolated hepatic and/or pulmonary mets amenable to resection
81
Although controversial, what is the standard of care for timing of chemotherapy for those with resectable metastatic colon cancer?
3 months of neoadjuvant and adjuvant FOLFOX
82
Adjuvant chemotherapy is indicated for which patients with colon cancer?
those with stage III disease or greater
83
What is the staging workup for rectal cancer?
- labs including CEA
- rigid proctoscopy
- CT C/A/P
- pelvic MRI or endorectal US to asses T/N stages
84
What is the CRM for rectal cancer?
- the circumferential tumor margin
- the total distance between the tumor and mesolectal fascia
- a particularly important prognostic indicator
85
Who gets neoadjuvant chemoradiotherapy for rectal cancer? What is the standard regimen?
- locally advanced tumors of the mid-to-distal rectum (T3 or greater or with any nodal involvement)
- 5000 cGy RT concurrently with 5-FU chemo over 5-6 weeks followed by surgery 8-12 weeks after
86
Who gets adjuvant chemotherapy for rectal cancer?
- those with stage III disease or greater who did not receive neoadjuvant therapy (understaged)
- high-risk stage II or greater who received neoadjuvant therapy (presumed to have been downstaged by chemoRT)
87
Describe the surgical management of rectal cancer.
- local excision for T1 lesions that are well-to-moderately differentiated with no perineurial or lymph-vascular invasion, that are less than 3cm, and that involve less than ⅓ the circumference (20% recurrence rate and can't evaluate nodes)
- local excision for T2 lesions in very poor surgical candidates
- tumors in the upper third of the rectum should have a mesolectal excision with 5cm distal margin
- tumors in the lower two thirds of the rectum should have a TME and LAR/APR with 2cm distal margins (1cm acceptable but not preferred)
88
What are the problems with local excision of T1 rectal cancers?
there is a 20% recurrence rate and you don't have the option to examine lymph nodes
89
What HPV serotypes are associated with anal SCC?
16 and 18
90
What is anal intraepithelial neoplasm (AIN)? How is it graded?
- a precursor lesion to SCC
- AIN I and II are low grade
- AIN III is high grade
91
What is the treatment for anal SCC?
- primary treatment is Nigro protocol chemoRT
- this includes 5-FU, mitomycin C, and 3K cGy RT
- APR is only indicated for persistent or recurrent SCC
- WLE is indicated for SCC of the anal margin (treat just like skin SCC)
92
What is considered the anal margin?
5cm from the squamous mucocutaneous junction
93
How is AIN treated?
- several topical treatments (imiquimod, 5-FU, photodynamic therapy, targeted destruction)
- key is surveillance every 4-6 months to monitor for conversion to SCC (low rate)
94
How is anal melanoma treated?
APR
95
What is the treatment for transverse colon cancer with local invasion of the head of the pancreas without metastasis?
en bloc Whipple with extended colectomy
96
What is the treatment for isolated peritoneal carcinomatosis secondary to colon cancer?
cytoreduction and HIPEC
97
What is the management of rectal cancer that appears to have a complete clinical response to neoadjuvant therapy?
still need resection given low sensitivity of imaging for pathologic response
98
What are cloacogenic, basaxoid, epidermoid, and mucoepidermoid carcinomas of the anal canal?
these are all histologic forms of anal SCC and should be treated with nigro protocol chemoRT
99
How is pouchitis of an IPAA managed?
- antibiotics (cipro/metro)
- supportive care
- budesonide enemas
100
What should you suspect in a patient with UC who underwent proctocolectomy with IPAA that has recurrent pouchitis?
misdiagnosis of Crohn's
101
How is severe, refractory pouchitis treated?
with excision and conversion to ileostomy
102
During laparoscopic exploration for acute appendicitis, the appendix appears normal but with inflamed TI. What do you do?
- suspect Crohn's
- if the cecum is uninvolved perform the app to prevent future diagnostic confusion
- if the cecum is inflamed, leave the appendix
- then treat medically for Crohn's flare
