Colorectal Flashcards by Brian Boyarsky

Colon secretes ___ and re-absorbs ____; mostly in the R colon and cecum

Secretes K; reasorbs Na and water

How well did you know this?

Not at all

Perfectly

4 layers of colon mucosa

Mucosa (columnar epithelium); submucosa, muclaris propria, serosa

How well did you know this?

Not at all

Perfectly

Asc/Dec, sigmoid colon are – intra/retroperit

Retroperitoneal

How well did you know this?

Not at all

Perfectly

Ascending and 2/3 of transverse colon are supplied by…

SMA (ileocolic, right and middle colic arteries)

How well did you know this?

Not at all

Perfectly

1/3 of transverse, descending colon, sigmoid colon and upper rectum are supplied by…

IMA

How well did you know this?

Not at all

Perfectly

What is arc of Riolan

Short direct connection between SMA and IMA

How well did you know this?

Not at all

Perfectly

80% of blood flow in colon goes to which bowel layers?

Mucosa, submucosa

How well did you know this?

Not at all

Perfectly

Splenic vein joins the ***

SMV to form the portal vein behind the pancreas

How well did you know this?

Not at all

Perfectly

IMV drains into…

Splenic vein

How well did you know this?

Not at all

Perfectly

The superior / middle / inferior rectal arteries

Superior: branch of IMA
Middle: branch of II (lateral stalks during LAR or APR contain middle rectal arteries)
Inferior: branch of internal pudendal – branch of II

How well did you know this?

Not at all

Perfectly

Where do the superior and middle rectal veins drain? What about inferior?

IMV –> portal vein

Inferior: internal iliac, caval

How well did you know this?

Not at all

Perfectly

Watershed areas of colon

Splenic flexure (Griffith’s point) – SMA/IMA junction

How well did you know this?

Not at all

Perfectly

What is Sudak’s point?

Rectum – superior and middle rectal junction

How well did you know this?

Not at all

Perfectly

Is colon or small bowel more sensitive to ischema/low-flow states?

Colon; fewer collaterals

How well did you know this?

Not at all

Perfectly

External sphincter

Inferior rectal branch of internal puddendal nerve (continuation of levator ani muscle)

How well did you know this?

Not at all

Perfectly

Internal sphincter

Involuntary / pelvic splanchnic nerves; continuation of muscularis propria; normally contracted

How well did you know this?

Not at all

Perfectly

Meissner’s vs. Auerbach’s plexus

Meissners: inner nerve plexux
Auerbach: Outer nerve plexus

How well did you know this?

Not at all

Perfectly

Pelvic splanchnic: sympa or para

Para

How well did you know this?

Not at all

Perfectly

Distance from anal verge to anal canal, rectum, recto-sigmoid junction

Anal canal: 0-5 cm
Rectum: 5-15 cm
Recto-sigmoid: 15-18cm

How well did you know this?

Not at all

Perfectly

Transition between anal canal and rectum

Levator ani

How well did you know this?

Not at all

Perfectly

What are crypts of Lieberkuhn?

Mucin-secreting goblet cells

How well did you know this?

Not at all

Perfectly

Treatment of colonic intertia

Subtotal colectomy

How well did you know this?

Not at all

Perfectly

Main nutrient of colonocyte

SCFA

How well did you know this?

Not at all

Perfectly

What is treatment for stump pouchitis

SCFA enema

How well did you know this?

Not at all

Perfectly

Treatment of infectious pouchitis

Flagyl

Denovilliers vs Waldeyers fasica

Anterior/Posterior

MC colon polyp

Hyperplastic; no cancer risk

MC neoplastic polyp in colon

Tubular adenoma

MC colon polyp to produce symptoms

Villious adenoma; 50% have cancer

Characteristics of colon polyps with increased cancer risk

>2cm, sessile, villous

If a polyp cannot be resected endoscopically, how do you get rid of it?

Segmental resection

Invasive colon cancer has eroded into...

Submucosa

Normal age for colon cancer screening

50 at normal risk; 40, or 10 years before youngest case

Colon cancer screening

q 10 year cscope high-sensitivity FOBT q 3 years and flex sig q 5 Q annual fecal occult blood

When is a polypectomy sufficient treatment?

t1; clear margins 2mm, well-differentiated, no vasc/lymphatic invasion; otherwise formal resection

T/F Red meat and fat are risk factors for colon cancer

True / oxygen radicals

Main genetic mutations of colon cancer

APC, DCC, p53, k-ras

Most common site of colon cancer

Sigmoid colon

Where does colon cancer spread first?

Nodes

#1 site of colon cancer mets

Liver; Number 2 is lung

How does colon cancer get to liver, lung?

Liver: PV Lung: Iliac vein

T/F isolated liver, lung mets can be resected for colon ca

True

How does rectal cancer mets to the spine?

Batson's venous plexus

Can colon cancer be resected en bloc?

Yes

T/F Mucoepidermoid colon cancer has worst prognosis

True

Best test for depth, invasion; recurrence, nodes

Trans-rectal ultrasound

For rectal pain with rectal cancer --- treatment

APR

What size margins for colon cancer

2cm

Best method of picking up intra-hepatic mets

Intra-operative ultrasound (3-5 mm)

What is an APR

Permanent colostomy; anal canal is excised with the rectum | - Impotence, bladder dysfunction (injured pudendal nerves)

If you cannot get 2cm margins with an LAR, the treatment is...

APR

Neoadjuvant Chemo-RT for rectal cancer

Can produce complete response, preserve sphincter function

t1 vs t2 vs t3 vs t4 colon ca

submucosa, muscularis propria, subserosa, through serosa

Can low recta T1's be excised transanally

Yes; negative margins, well-differentiated

Who gets NAC/RT colon cancer

Stage 2, 3

Chemo for colon cancer

FOLFOX (5-FU, leucovorin, oxaliplatin)

Most common site of injury in colon cancer RT

Rectum; vasculitis, thrombosis, ulcers, strictures, bleeding

Is FAP AD?

Yes

When are polyps present in FAP?

Puberty

When do you get a total colectomy in FAP?

Age 20

Where else can you get polyps in FAP?

Duodenum

MCC death in patients with FAP who have undergone colectomy?

Peri-ampullary tumors of duodenum

What is Gardner's syndrome?

Colon Cancer (a/w APC gene) and intra-abdominal desmoid tumors/osteomas

What is Turcot's syndrome?

APC gene, brain tumors

Lynch syndrome

5% population; AD | - A/W DNA MMR gene

Lynch II syndrome also increases risk of...

Ovarian, endometrial, bladder, stomach

What operation do you need for Lynch syndrome?

Total proctocolectomy with first cancer operation

Lynch L or R sided cancer

When does surveillance colonoscopy begin for Lynch?

25 or 10 years before primary relative

For HNPCC, do you need colonoscopy?

No; flex sig

Sigmoid volvulus is more common with low or high fiber diet

High fiber

In what types of patients is sigmoid voluvlus more common

Psychiatric, neurologic dysfunction, laxitive absue

Treatment for sigmoid voluvlus

Decompress with colonscopy; bowel prep, and perform sigmoid colectomy during same admission

Cecal volvulus

Can appear as SBO; R hemi colectomy; can try cecopexy is colon is viable and patient is frail

UC involves which bowel layers

Mucosa and submucosa

Does UC spare anus?

Yes

Crypt abscess in UC or Crohn's

Pseudo-polyps UC or Crohn's

Cobblestoning in UC vs. Crohn's

Crohn's

In UC, bleeding is universal and has mucosal friability with pseudopolyps

True

Medical treatment of UC

Salfasalazine, Liperamide

For acute flares of UC

Steroids; Cipro/Flagyl

Indications for surgery with toxic colitis and toxic megacolon

Pneumoperitoneum, diffuse peritonitis; uncontrolled sepsis, major hemorrhage

Perforation with UC vs. Crohn's

Transverse colon: UC | Crohn's distal ileum

Risk of cancer in UC

1%/year starting 10 years after initial diagnosis

MC extra0intestinal manifestation in children

FTT

Treatment poyderma gangrenosusm

Steroids

< 2 cm low rectal carcinoid

WLE with negative margins

> 2 cm rectal carcinod or invasion into muscularis propria

APR

Most likley location colon perf with obstruction

Cecum

Number 1 and 2 cause of colonic obstruction

Cancer, diverticulitis

What is Ogilvie's syndrome

Massively dilated colon which can perforatea

Treatment Ogilvie's syndrome

Replace electrolytes, discontinue anti-motility agents, i.e. Morphine; NGT, neostigmine

If colon > 10 cm in Ogilbie's syndrome

Decompression with colonscopy and neostigmine, cecostomy if that fails

Treatment of amoebic colitis

Flagyl (colon --> liver) | * Mexico, fecal-oral

Actinomyces most common location

Cecum

Yellow-white sulfer granules

Actinomces -- penicillin

Tagged RBC scan vs. arteriography for LGI bleed

> 0.1 cc/min; >0.5cc/min

MCC complication following diverticulitis

Abscess

Need to resect all of sigmoid colon down to superior rectum for diverticulitis

True

MCC colo-vesicular fistula

Diverticulitis

Best test of colo-vesicular fistula

Cystoscopy

Vessels that bleed in diverticulosis

Vasa rectum; arterial bleeding

Usual first step for diverticular bleed

Colonoscopy

If massive LGI bleed

Angiography; to localize area for surgery; or highly selective coil embolization

Most sensitive test for LGI bleed

Tagged RBC scan

Angiodysplasia bleeding is typically on L or R colon

R; venous bleeds

T/F 20% patients with angiodysplasia have AS

True

Usually ischemic colitis involves R or L colon

SMA/IMA junction

Grifftith's point

When to perform a colon resection for ischemic colitis

Gangrenous colitis; peritonitisl black bowel; sepsis; perforation * Otherwise NPO/ABX/IVF

Key histologic finding for C. diff colitis

PMN inflammation of mucosa and submucosa

Neutropenic typhlitis (enterocolitics)

Follows CTX with WBC low (nadir); can mimic surgical disease; can see pneumatosis intestinalis; surgery only for free perforation. Treatment is abx

Can Yersinia mimic appendicitis

Yes

MCC of acquired megacolon?

Trypanosoma cruzi (2/2 destruction of nerves)