Colon, Rectum, Anus Flashcards
What are the special features of the colon?
- Haustrations
- Appendices epiploicae
- Taenia coli
What are the components of taenia coli
- Taenia libera
- Taenia mesocolica
- Taenia omentalis
[Segment of the colon]
widest, least likely to obstruct
cecum
[Segment of the colon]
thinnest wall, most common site of perforation
cecum
[Segment of the colon]
what is the length of the ascending colon?
13cm
[Segment of the colon]
Which is higher, the left or right colic flexure?
left
[Segment of the colon]
what is the narrowest portion, most common site of obstruction
sigmoid colin
[Segment of the colon]
most common site of volvulus
sigmoid colon
[Segment of the colon]
Extremely mobile segment
sigmoid
What is the embryologic origin of transverse colon?
- Proximal - midgut
2. Distal - hindgut
[Segment of the colon]
long straight “tunnel view”
Descending colon
[Segment of the colon]
external bulging bluish mass indenting the colon, descending with respiration
splenic flexure
[Segment of the colon]
“cathedral ceiling” appearance
Transverse colon
[Segment of the colon]
“fool’s cecum”
Hepatic flexure
[Segment of the colon]
spiral configuration which can cause the taenia to approximate each other
Hepatic flexure
[Segment of the colon]
mercedes benz sign
cecum
[Segment of the colon]
pouting lips sign
ileocecal valve
[Segment of the colon]
bow and arrow sign
appendiceal orifice
What are the branches of your SMA that supplies the colon?
- Ileocolic
- Right colic
- Middle colic
What are the branches of your IMA that supplies the colon?
- Left colic
- Sigmoidal branches
- Superior rectal
What are the arteries that anastomose in marginal artery of Drummond?
Terminal branches of the SMA and IMA
What do you call the anastomosis between the middle colic artery and the SMA and the ascending branch of the left colic artery of the IMA?
Arc of Riolan or meandering artery of Moskowitz
The inferior mesenteric vein joins this vein before draining to the portal vein
Splenic vein
What are the foregut derivatives of the GIT?
- Esophagus
- Stomach
- Pancreas
- Liver
- Duodenum
What are the midgut derivatives of the GIT?
- Small intestine
- Ascending colon
- Proximal colon
- Transverse colon
What are the hindgut derivatives of the GIT?
- Distal transverse
- Descending
- Rectum
- Proximal anus
what do you see in the water soluble contrast enema in patients with Sigmoid volvulus?
birds beak deformity
What are the plain abdomen radiographs findings in patients with sigmoid volvulus?
- Inverted U shaped
- Sausage loop
- Omega sign
- Coffee bean sign
- Bent inner tube sign
What is the surgical management for strangulation/unprepared bowel in patients with sigmoid volvulus?
Construction of colostomy Hartmann’s pouch
What is the surgical management for patients with cecal volvulus?
Right hemicolectomy with primary ileotransverse anastomosis
[Diagnosis]
loop extending from the RLQ to LUQ
Cecal volvulus
[Diagnosis]
loop extending from the LLQ to the RUQ
Sigmoid volvulus
What is the standard initial therapy for acute sigmoid volvulus?
Endoscopic Detorsion / rigid proctosigmoidoscopy
What is the treatment for failed sigmoid volvulus decompression?
Emergency Laparotomy
and those with peritonitis too
What are the Abdominal CT scan findings in patients with diverticulitis?
- Sigmoid diverticula
- Thickened colonic wall >4mm
- Inflammation with pericolic fat with or without collection of contrast material or fluid
In patients with uncomplicated diverticulitis, how long will you administer a clear liquid diet and broad spectrum antibiotics?
7-10 days
What is the surgical management for patients with diverticulitis with abscess
drainage
What are the criteria for admission in patients with uncomplicated diverticulitis?
- High documented fever
- Immunocompromised status
- Severe abdominal pain
- Significant or unstable comorbid conditions
- Inability to tolerate oral intake
[Determine the hinchey Stage]
Diverticulitis with a pericolic abscess
Stage I
Tx: Percutaneous drainage of abscess, resection with primary anastomosis without diverting stoma
[Determine the hinchey Stage]
diverticulitis with a distant abscess (retroperitoneal, pelvic)
Stage II
Tx: percutaneous drainage of abscess, resection with primary anastomosis
[Determine the hinchey Stage]
Purulent peritonitis
Stage III
Tx: Hartmann procedure, Diverting colostomy plus percutaneous draninage
[Determine the hinchey Stage]
fecal peritonitis
Stage IV
Tx: hartman procedure plus diverting colostomy plus percutaneous drainage
What is the preferred surgical treatment for patients with right sided diverticulitis?
Segmental ileocecal resection
What is the anatomic marker to distinguish LGIB from UGIB
Ligament of treitz
[Location of LGIB]
Hematochezia
LGIB from left side of colon
Rule out massive UGIB
[Location of LGIB]
Maroon-colored stools
LGIB from right side of colon
[Location of LGIB]
melena
Cecal bleeding
BUT TYPICALLY SEEN IN UGIB
What is the rationale behind doing NGT aspiration in patients with suspected LGIB?
Determine the presence or absence of blood proximal to the ligament of treitz
What is the test of choice to identify site of LGIB (which can also be therapeutic)
Colonoscopy
What are the drug choices for vasoconstricting agents in patients with LGIB?
- Vasopressin
- Alcohol
- Morrhuate sodium or Sodium tetradecyl sulfate
[Inflammatory bowel disease]
Appendectomy is protective
ulcerative colitis
[Inflammatory bowel disease]
smoking may prevent disease
ulcerative colitis
[Inflammatory bowel disease]
affects any part of the GIT, cobblestone appearance, transmural
Crohn Disease
What is the pathognomonic feature of Crohn Disease?
Granulomas
[Inflammatory bowel disease]
megacolon is frequent
ulcerative colitis
What are the indications for surgery in patients with ulcerative colitis?
- Active disease unresponsive to medical therapy
- Risk of CA
- Severe bleeding
What are the indications for surgery in patients with crohn disease?
- Management of complications
2. Resect a segment that is grossly involved with the disease
[Colorectal CA Pathogenesis: Gene involved]
Normal epithelium to Dysplastic epithelium
APC
[Colorectal CA Pathogenesis: Gene involved]
Early adenoma to intermediate adenoma
KRAS
[Colorectal CA Pathogenesis: Gene involved]
Late adenoma to CA
p53
[Colorectal CA Pathogenesis: Genetic pathways]
chromosomal deletions and aneuploidy; tumors occur in the more distal colon, associated with a poorer prognosis
LOJ
[Colorectal CA Pathogenesis: Genetic pathways]
results from errors in mismatch repair and microsatellite instability; tumors are more likely right sided with diploid DNA; better prognosis
Replication error pathway
[Colorectal CA Pathogenesis: Genetic pathways]
Also called serrated methylated pathway, epigenetic alterations caused by hypo or hypermethylation of a promoter region resulting to either gene activation or silencing; observed in serrated type of polyps
CpG island methylation pathway
Most common location of colorectal polyp?
rectosigmoid area
What is the most common histologic type of colorectal polyp?
Hyperplastic polyp
Hyperplastic colorectal polyp are considered pre-malignant is its size becomes _____
> 2cm
What is the histologic type of colorectal polyp that is asociated with UC and CD?
Inflammatory or pseudopolyp
Which histologic type of colorectal polyp is considered premalignant and is treated like an adenomatous polyp?
Serrated polyp
____ classification is a clinical tool used to describe the degree of invasion into a pedunculated polyp
Haggitt
[Neoplastic Polyp]
Most common type
Tubular adenoma
CA risk <5%
[Neoplastic Polyp]
Seen throughout the large intestine
Tubulovillous adenoma
CA risk 25%
[Neoplastic Polyp]
predominantly in the rectum
Villous adenoma
CA risk 40%
[Neoplastic Polyp]
sessile, velvety, cauliflowerlike grossly
Villous adenoma
CA risk 40%
What is the clinical classification used only for sessile colorectal polyp?
Kikuchi Classification
[Haggitt Classification]
CA invading though the muscularis mucosa but limited to the head of a peduculated polyp
Level 1
[Haggitt Classification]
CA invading the neck of a pedunculated polyp
Level 2
[Haggitt Classification]
CA invading the stalk of a pedunculated polyp
Level 3
[Haggitt Classification]
CA invading into the submucosa of the bowel wall below the stalk of a pedunculated polyp
Level 4
Risk of LN metastasis: 12 to 25%
Oncologic resection is warranted for what Kikuchi or Haggitt Grade
Kikuchi SM 3
Haggitt 4
[Kikuchi Classification]
Superficial 1/3 of the submucosa is involved
SM 1
Nodal mets = 2%
[Kikuchi Classification]
Superficial 2/3 of the submucosa is involved
SM 2
Nodal mets = 8%
[Kikuchi Classification]
deep 1/3 of the submucosa is involved
SM 3
Nodal mets = 23%
Early onset colorectal CA due to HNPCC are predominantly seen in which side of the colon? (Right or left)
Right
What are the components of your Amsterdam Criteria for diagnosis of HNPCC?
3-2-1 rule
3 relatives have histologically verified colorectal CA (one must be first degree relative)
2 successive generations
1 relative must have received a diagnosis before age 50
Exclude FAP
What variant of HNPCC wherein there is an isolated early onset colorectal CA?
Lynch Syndrome 1