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Colon actively secretes: K and HCO3

Rectal Arteries:

  • Superior rectal artery off IMA;

  • Middle off Internal iliac;
  • Inferior off Internal pudendal (off Internal iliac)


External sphincter innervated:

  • By inferior rectal branch of internal pudendal nerve
  • And perineal branch S4.

Transformation of polyps to CA: takes approx. 8 years

1/2 of colon CA has:

  • ras mutation
  • p53 absent in 85%
  • DCC (deleted in colon CA) in 70%

Dietary risk factors for developing colon cancer:

  • High fat diet
  • Low fiber diet


Tumor Grading:

  • T1: (limited to submucosa)
    • Rectal Adeno-CA can be excised trans-anally
  • T2: 20% are node +
    • APR; do not do transanal if poor differentiation, neuro/vasc invasion.

  • Stage III colon CA (node +) gets chemo, no XRT
  • Stage II, III rectal CA gets chemo and XRT

Squamous cell CA of anal canal:

  • Do not preform surgery
  • Tx with Nigro protocol (chemo and XRT)
  • APR for recurrent & residual disease.

Familial adenomatous polyposis:

  • Automsomal dominant,
  • CA by age 40
  • APC gene
  • Need total colectomy prophylactically
  • Have UGI polyps as well (Need to survey duodenum for CA)
  • Also develop desmoids - benign, but very difficult to manage
  • Sulindac makes polyps recede

Hereditary Non-polyposis Colon CA:

  • Lynch I: R sided, multiple CA's, young patients
  • Lynch II: a/w CA of ovary, bladder, stomach
  • Both a/w DNA mismatch repair gene mutations
  • Amsterdam criteria:
    • ​3 relatives with at least 1 1st degree relative
    • 2 generations involved
    • 1 relative diagnosed before 50 years of age

Gardner's syndrome: colon CA and desmoid tumors

Turcot's syndrome: colon CA and brain tumors

Peutz Jeghers: polyposis (not colon CA) and mucocutaneous pigmentation

Sigmoid volvulus: decompress with scope, prep bowel, do sigmoid colectomy after admission

Cecal volvulus: likely will not decompress, take to OR

  • Most recommend R hemicolectomy with ileo-transverse anastomosis
  • Cecopexy is alternative

Carcinoid of appendix:

  • Clear base and < 2 cm = Appendectomy only
  • >2 cm or base involved then R hemicolectomy

If operating for appy and find normal appy and Crohn's disease: take appendix (unless cecum involved in inflammation). Does not increase fistula rate.

Perianal abscess in Crohn's: Incision and drainage as with any abscess

In Ulcerative Colitis: Preforming a proctocolectomy:

  • Does not help the sclerosing cholangitis or arthritis

  • May help skin, anemia.

HLA B27: a/w sacroiliitis

Pouchitis:

  • Tx with flagyl or short chain fatty acid enemas
  • 1/3 never develop, 1/3 only 1 episode, 1/3 chronic.

Pyoderma gangrenosum: Tx with Dapson and/or steroids (topical or systemic)

Fissure in Ano:

  • 10% anterior in women, nearly all others are in the posterior midline.
  • Fissure not in midline - think IBD, TB, syphilis.
  • Tx with Sitz baths, regular loose BM (water/fiber)
  • If persists then lateral internal sphincterotomy
  • Some try nitroglycerine creams (increase O2 for ischemia) or botox (relax sphincter)

Bowen's disease:

  • Intraepidermal squamous cell carcinoma
  • Only 5% invasive
  • Tx: wide local excision

Perianal Paget's:

  • Rare intra-epidermal neoplasm of apocrine glands
  • Long pre-invasive phase.
  • (+)PAS stain

Patients with Colonic AVM:

  • 1/2 of patients have CAD
  • 1/4 of patients have aortic stenosis

Campylobacter infectious colitis:

  • May see aphthous ulcers on colonoscopy

Neutropenic Typhlitis (Enterocolitis):

  • Follows chemotherapy when WBCs are low
  • Can mimic surgical disease
  • Can often see pneumatosis on plane film
  • TX: antibiotics; patients will improve when WBCs increase

Pages in category "ColoRectal"

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