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Flashcards in CRC Deck (93):
1

Superior mesenteric artery

Ascending colon Proximal 1/2 transverse colon

2

Inferior mesenteric artery

Distal _ transverse colon Descending colon Sigmoid colon Upper _ rectum

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Middle and inferior rectal artery

Lower 1/2 rectum Anus

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Bowel wall layers

Mucosa Submucosa Muscularis Serosa (except middle and distal rectum)

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Other structures in bowel

Taeniae coli Haustra Appendices epiploicae

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Colonic motility

Segmentation contractions and mass contractions Movement: 18-48 h

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Acceleration of colonic transit time

Emotional states Diet Disease Infection Bleeding Drugs

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Typical defecation pattern

Once/24 hours May vary from 8-72 hours

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Changes in bowel habit: Constipation

Ability to pass flatus but not stool

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Changes in bowel habit: Obstipation

Inability to pass stool or flatus

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Person presenting with significant change in bowel habits

Must be evaluated for possibility of serious disease

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Colonic Bacteria

Greatest number and variety of bacteria Majority: anaerobes Also: gram + and - aerobes Degrade bile pigments and produce vitamin K Infection risk in colorectal surgery

13

Pre-op bowel prep

Mechanical cleansing Oral abx IV abx pre-op and 24 h

14

Dx evaluation tools

Digital rectal exam Rigid sigmoidoscopy Flexible fiberoptic sigmoidoscopy Fiberoptic colonoscopy Abdominal X-ray series (flat and upright) Barium enema CT scan Angiography Nuclear bleeding scan

15

Anastamosis

Surgical union of two hollow or tubular structures Types: End-to-end, end-to-side, side-to-end, side-to-side

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End-to-End Anastamosis

Performed when 2 segments of bowel are roughly the same caliber Most often employed in rectal resections, but may be used for colocolostomy or small bowel anastamoses

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End-to-Side Anastamosis

Used when one limb of bowel is larger than the other Used in chronic obstruction

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Side-to-End Anastamosis

Used when proximal bowel is smaller caliber than distal bowel Ileorectal anastamosis May have less tenuous blood supply than end-to-end anastamosis

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Side-to-Side Anastamosis

Allows a large, well vascularized connection to be created on the antimesenteric side of two segments of intestine Used in ileocolic and small bowel anastamoses

20

Resection

Operative removal of organ or gland

21

Anterior resection

Used to describe resection of rectum from an abdominal approach to the pelvis with no need for a perineal, sacral, or other incision

22

High anterior resection

Resection of distal sigmoid colon and upper rectum Used for benign lesions and disease in rectosigmoid junction (diverticulitis)

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Low anterior resection

Removes lesions in the upper and mid rectum

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Extended low anterior resection

Removes lesions located in distal rectum, but several cm above sphincter

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Abdominoperineal resection (APR)

Involves removal of entire rectum, anal canal, and anus with construction of permanent colostomy from descending or sigmoid colon

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-Ectomy

Denotes operative removal of an organ or gland

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-Stomy

Denotes artificial or surgical opening -When two organs precede the suffix, the opening is between them

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Colostomy

Surgically created connection between colon lumen and abdominal wall skin for diversion of fecal stream

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Loop Colostomy

Also double-barrel Usually temporary Loop ileostomy

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End colostomy

One lumen Most permanent stomas

31

Fistula

An abnormal tract between two hollow organs or an organ to the skin -Infectious -Inflammatory -Malignant -Surgical

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Hartmann's Procedure

Resect sigmoid colon Create end colostomy with L colon Close rectal stump and leave in peritoneal cavity (Hartmann's) Alt: Bring rectal stump to abd wall (Mucous Fistula)

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Proctum

Synonym for rectum

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One stage

Diseased segment resected and anastamosis performed at same operation

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Two stage

1st: create proximal stoma and resect diseased segment 2nd: if not already done, resect disease, then perform anastamosis and reverse colostomy

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Three stage

3rd: reverse colostomy

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Ulcerative Colitis

Only affects colon/rectum Long standing: colon is foreshortened and lacks haustral markings ("Lead pipe" colon) Cure: remove affected intestinal segment (colon and rectum)

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Thumb Printing

Similar appearance of thumbs protruding into intestinal lumen Caused by thickened haustral mucosal folds Abd thumb printing is sign of intestinal ischemia Observed in exacerbations of conditions like UC

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UC: Emergency surgery

Massive life-threatening hemorrhage -Proctectomy and creation of permanent ileostomy or ileal pouch-anal anastamosis

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Complications of UC

Toxic megacolon Fulminant colitis -Total abdominal colectomy with end ileostomy (with or without mucus fistula)

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UC: Elective surgery

Intractability despite max medical therapy High-risk development of major complications (aseptic necrosis of joints from chronic steroid use) At risk of developing colorectal carcinoma

42

UC: Elective resection procedure

Total proctocolectomy with end ileostomy TREATMENT OF CHOICE: Restorative proctocolectomy with ileal pouch-anal anastamosis

43

Crohn's Disease: Areas affected

Any portion of the intestinal tract, from mouth to anus -Skip lesions -Rectal sparing (40%) -Terminal ileum and cecum involved in 41% -Small intestine involved in 35%

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Crohn's Disease: When to do surgery

Complications of the disease

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String sign

Narrowing of loop of bowel-- thin stripe of contrast within the lumen looks like a string Observed in Crohn's

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Crohn's: Internal fistulae and/or intra-abdominal abscess

CT guided drainage of abscess Resection of fistulae with segment of bowel

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Crohn's: Strictures/Obstruction

Tx: resection or stricturoplasty

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Crohn's: creation of stroma

Consider if patient is: -Hemodynamically stable -Septic -Malnourished -Receiving high-dose immunosuppressive therapy -Extensive intra-abdominal contamination

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Diverticular Disease

Mucosal herniation through muscular wall usually at penetration of marginal artery (false diverticula) 5th -- 8th decade Low-fiber diet Chronic constipation Sigmoid colon

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Diverticulosis

Multiple colonic diverticuli 80% asx finding on exam Sx: recurrent abd pain, usually LLQ. Constipation, diarrhea, or alternating Tx: high fiber diet

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Diverticulitis

Infection or perf of diverticulum, leading to infection/inflammation of peridiverticular tissue Abscess formation or generalized peritonitis -LLQ pain and tenderness -Alteration in bowel habits -Fever, chills -Leukocytosis -LLQ "mass"

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Contraindicated tests in diverticulitis acute stage

Barium enema Colonoscopy

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Initial tx of diverticulitis

NPO, IVF IV Abx (cipro/flagyl) -Sick patients need most aggressive therapy

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Diverticulitis: perforation tx

Emergent surgery Resect perforated segment and create proximal colostomy (Hartmann) Post-op: treat infection aggressively Delay 2nd stage 6-12 weeks

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Diverticulitis: Abscess tx

Emergent drainage: open or image guided Treat infection Many can undergo one-stage procedure electively If fail: treat as perf

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Diverticulitis: Obstruction tx

Incomplete: prep bowel; 1 stage operation Complete: unprepped bowel; 2-3 stage operation *CA is a cause of obstruction*

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Diverticulitis: Fistula

Colovesicular, colovaginal, coloenteric -If no sepsis or abscess: one stage repair. -Sepsis or abscess: two stage repair.

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Hemorrhoids: etiology

Cushions of submucosal tissue consisting of venules and smooth muscle fibers located in the upper anal canal become displaced downward during straining at defecation causing dilation of venules

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Location of hemorrhoids

Left lateral: 3:00 Right posterior: 7:00 Right anterior: 11:00

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Internal hemorrhoids

Above dentate line Covered by insensitive rectal mucosa S/S: discomfort, bleeding, prolapse

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External hemorrhoids

Below dentate line Covered by well innervated anoderm S/S: severe pain from thrombosis

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Grading of hemorrhoids

I. Remain above dentate line II. Prolapse through anus with straining but reduce spontaneously III. Prolapse through anus with minimal strain and/or require manual reduction IV. Continuous prolapse and/or cannot be manually reduced

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Treatment of hemorrhoids: I, II

Diet and lifestyle

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Treatment of hemorrhoids: I, II-- unresponsive

Rubber band ligation Alt: infrared photocoagulation, sclerotherapy,

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Treatment of hemorrhoids: III, IV

Hemorrhoidectomy

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Treatment of hemorrhoids: thrombosed external

Excise thrombus

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Treatment of hemorrhoids: Strangulated

Hemorrhoidectomy

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What is the most common GI cancer?

Carcinoma of the colon and rectum -40s, 70s-80s -Male = female -RF: genetics, diet, IBD

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Sx: right colon cancer

Weight loss Mass Virchow's node Blummer's shelf Anemia

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Sx: left colon cancer

+/- weight loss Rectal bleeding Blummer's shelf Obstruction

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Sx: Rectum cancer

Rectal bleeding Tympany Obstruction

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ACS recommendations: no first degree family hx

Annual DRE starting age 40 Annual fecal occult blood starting age 40 Sigmoidoscopy age 50 and q 3-5 years

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ACS recommendations: positive CRC in first degree relative

Colonoscopy or BE starting age 35-40 and q 5 years

74

Pre-malignant polyps

Adenomatous polyps Subdivisions: -Tubular -Tubovillous -Villous adenoma (> 2 cm in size, most commonly malignant) Can be: sessile or pedunculated Tx: colonoscopic polypectomy

75

Large bowel CA

Most common source of large bowel obstruction in adults Sx depend on site TEST OF CHOICE: ENDOSCOPY Tx: Biopsy, CEA, CT scan of abdomen (staging)

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Classic sign of large bowel CA

Apple core lesion

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Tx: CRC

Wide surgical resection of lesion Include venous and lymphatic drainage Minimum 2 cm margin (usually 5 cm or more) Chemo for nodal mets Radiation for RECTAL (not colon)

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Who needs total or subtotal colectomy?

Patients with fulminant colitis, attenuated FAP, or synchronous colon carcinomas

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CRC Staging: A

Confined to mucosa 5 year survival: 85-90%

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CRC Staging:B1

Negative nodes; extension into, but not through, the muscularis propria 5 yr survival: 70-75%

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CRC Staging: B2

Negative nodes; extension through the muscularis propria 5 yr survival: 60-65%

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CRC Staging: C1

Same level of penetration as B1 but with positive nodes 5 yr survival: 30-35%

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CRC Staging: C2

Same level of penetration as B2 but with positive nodes 5 yr survival: 25%

84

Rectal carcinoma

Adenocarcinoma Tx: APR (abdominoperineal resection) or LAR (low anterior resection) Fulguration-- used in stage A Adjuvant chemo

85

Anal Carcinoma

Squamous cell type Tx: Nigro protocol (5 fluorouracil and mitomycin and medical radiation if

86

What is the most common cause of large bowel obstruction?

Colon cancer (65%) Other: diverticular stricture (20%), volvulus (5%), other (10%; IBD, benign tumors, FB, fecal impaction)

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Sx of obstruction

Crampy intermittent abdominal pain Abd distension No BM No flatus Previous surgery Hypo/hyperactive bowel sounds Metallic quality Ascites--intravascular volume depleted *Severe, persistent pain = strangulation or perforation*

88

Large Bowel Obstruction: lab values

BUN/CR: > 20:1 Hypernatremia Urine electrolytes Hemoconcentration Acidosis Leukocytosis

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Possible locations of obstruction

Proximal Mid-gut Distal

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Obstruction: Radiology

Supine and erect abd x-ray Erect CXR (including diaphragm) Single-contrast barium enema CT scan

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Colon cut-off sign

Abrupt termination of gas in proximal colon at level of splenic flexure Most common = acute pancreatitis

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Tx of bowel obstruction

Fluid resuscitation and monitoring NG tube for decompression Pre-op abx Exploratory laparotomy

93

Bowel obstruction complications

Fluid and electrolyte imbalance Dehydration... hypovolemic shock Ischemia of bowel leading to strangulation, necrosis, perforation Peritonitis Sepsis Death