Surgery- Colon and Rectum – Flashcards
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What are the white lines of Toldt?
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Lateral peritoneal reflections of the ascending and descending colon.
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What parts of the GI do not have a serosa?
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Esophagus, middle, and distal rectum.
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What are the major anatomic differences between the colon and small bowel?
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Colon has taeniae coli, haustra, and appendices epiploicae, whereas the small intestine is SMOOTH.
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What is the blood supply to the PROXIMAL rectum?
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IMA--> Superior hemorrhoidal (superior rectal)--> Proximal rectum.
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What is the blood supply to the MIDDLE rectum?
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Internal Iliac-->Middle hemorrhoidal (middle rectal)-->Middle rectum
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What is the blood supply to the DISTAL rectum?
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Pudendal artery-->Inferior hemorrhoidal (inferior rectal)--> Distal rectum * Pudendal artery is a branch of the hypogastric
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What is a colorectal carcinoma?
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Adenocarcinoma of the colon or rectum
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What is the incidence of colorectal cancer?
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Most COMMON GI cancer.
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What are the dietary risk factors for colorectal cancer?
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Low-fiber, high fat diets.
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What are the genetic risk factors for colorectal cancer?
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Family history is important when taking history (FAP, Lynch's syndrome)
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What else puts one at risk for colon cancer?
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IBD, though UC;Crohn's. Age, previous colon cancer also factors
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Lynch's syndrome?
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HNPCC- Hereditary NonPolyposis Colon Cancer- AD inheritance of high risk for development of colon cancer.
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What are the current recommendations of screening for colorectal cancer?
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Starting at age 50, at least ONE of the following: - Colonoscopy every 10 years - Double contrast barium enema every 5 years - Flex sigmoidoscopy every 5 years - CT colonography every 5 years.
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What are recommendations if someone in the family has contracted colon cancer, as far as screening is concerned?
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- Colonoscopy at age 40, OR at least 10 years before the age at diagnosis of the youngest first-degree relative, and every 5 years thereafter.
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What percentage of adults with a guaic stool test positive for colon cancer?
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10%.
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From which side is melena more common, as far as colon cancer is concerned?
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RIGHT-sided colon cancer
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From which side is hematochezia more common, as far as colon cancer is concerned?
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LEFT-sided colon cancer
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What are the signs/symptoms of colon cancer?
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- MOST COMMON: Hematochezia or mucus - Tenesmus - Feeling of incomplete passage of stool
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What diagnostic tests are helpful for colon cancer?
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History and PE (10% of colon cancer cases are palpable on rectal exam)
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What disease does microcytic anemia signify, until proven otherwise?
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COLON CANCER
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What is the pre-op test panel for colorectal cancer?
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- History and PE - LFTs, CEA, CBC - Basically everything
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Is CEA useful?
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Not for screening, but for progression. Offers no proven survival benefits.
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What unique diagnostic test is helpful in patients with rectal cancer?
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Endorectal US
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How are colorectal tumors staged?
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TMN Staging
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What is stage 1 colon cancer?
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Invades the submucosa or muscularis propria (T1-2, N0, M0) Survival rate: 90%
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What is stage 2 colon cancer?
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Invades through muscularis propria or surrounding structures, but no nodes are effected (T3-T4, N0, M0) Survival rate: 70%
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What is stage 3 colon cancer?
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Positive nodes, but NO distant mets (T: Any, N1-3, M0) Survival rate: 50%
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What is stage 4 colon cancer?
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Positive distant mets (T: Any N: Any M1) Survival rate: 10%
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What percentage of patients presenting with colon cancer have liver mets?
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20%
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What are the treatment options for colon cancer?
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- Resection: Wide resection of lesion and its regional lymphatic drainage
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What do all rectal cancer operations include?
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Total mesorectal excision- Remove the rectal mesentery, including lymph nodes
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What is the lowest LAR (low anterior resection) possible?
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Coloanal anastomosis (anastamosis normal colon directly to anus)
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What surgical margins are needed for colon cancer?
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Traditionally, ;5 cm; margins must be at least 2 cm
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What is the minimal surgical margin for rectal cancer?
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2 cm.
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How many lymph nodes should be resected with a colon cancer mass?
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12 LNs minimum, for staging. May also improve prognosis.
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What is the adjuvant treatment for stage 3 colon cancer?
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5-FU and chemo
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What is the adjuvant treatment for T3-T4 colorectal cancer?
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Preoperative radiation therapy and 5-FU chemo as a radiosensitizer.
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What is the most common site of distant mets from colorectal cancer?
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Liver
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What is the treatment of liver metastases from colorectal cancer?
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Resect with ;1cm margins and administer chemo if feasible.
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What is the surveillance regimen?
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- PE - Stool guiac - CBC - CEA, - LFTs Every 3 months for 3 years, then every 6 months for 2 years.
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Why is follow up so important within the 3 years post-op?
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~90% of colorectal occurences are within 3 years of surgery.
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What are the most common causes of colonic obstruction in the adult population?
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Colon cancer, diverticular disease, colonic volvulus.
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What are colonic and rectal polyps?
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Tissue growth into bowel lumen, usually consisting of mucosa, submucosa, or both.
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How are polyps classified?
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Sessile: flat Pedunculated: On a stalk
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What is the histologic classification of inflammatory polyps?
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As in Crohn's Disease or UC
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What is the histologic classification of hamartomatous polyps?
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Normal tissue in an abnormal configuration
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What is the histologic classification of hyperplastic polyps?
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Benign- normal cells with no malignant potential
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What is the histologic classification of neoplastic polyps?
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Proliferation of undifferentiated cells, premalignant or malignant.
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What are the subtypes of neoplastic polyps?
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- Tubular adenomas: Usually pedunculated - Tubulovillous adenomas - Villous adenomas (usually sessile and look like broccoli heads)
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What determines malignant potential of an adenomatous polyp?
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Size, histologic type, atypia of cells.
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What is the most common type of adenomatous polyp?
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Tubular (85%)
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What is the correlation between size and malignancy?
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The larger the polyp, the more likely the malignancu
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Which histology of adenomatous polyps carry with it the greatest chance of malignancy?
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Villous>tubovillous>tubular ** This is also the order of most common... Sadly VILLANY!
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Where are most polyps found?
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Rectosigmoid
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What are the signs/symptoms of polyps?
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Bleeding (red or dark blood), change in bowel habits, mucus per rectum, electrolyte loss, totally asymptomatic
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What are the diagnostic tests for polyps
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Colonoscopy is best
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What is the treatment for polyps?
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Endoscopic resection (snared)
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What is familial polyposis?
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FAP (familial adenomatous polyposis
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What are the characteristics of FAP?
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Hundreds of adenomatous polyps within the rectum and colon that begin developing at puberty, cancer will develop by the age of 40-50 if not treated.
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What is the inheritance pattern of FAP?
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Autosomal dominant (i.e. 50%)
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What is the genetic defect in FAP?
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APC (Adenomatous polyposis coli) gene
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What is the treatment of FAP?
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Total protocolectomy and ileostomy
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What is Gardner's Syndrome?
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Neoplastic polyps of the small bowel and colon. Cancer by age 40 in 100% of patients untreated (like FAP)
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What are other associated findings in Gardner's Syndrome?
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Desmoid tumors (in abdominal wall cavity) osteomas of the skull (seen on x-ray), sebaceous cysts
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What is a neumonic for Gardner's Syndrome?
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Gardner's plant SOD: S- Sebaceous cysts O- Osteomas D- Desmoid tumors
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What is a desmoid tumor?
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Tumor of the musculoaponeurotic sheath, usually of the abdominal wall. Benign
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What is the treatment of Gardner's Syndrome?
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Total proctocolectomy and ileostomy
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What is Peutz-Jegher's Syndrome?
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Hamartomas throughout the GI tract (mostly in the Jejunum ileum)
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What is the associated cancer risk from polyps?
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Increased
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What is the associated cancer risk for women with Peutz-Jeghers?
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Ovarian cancer
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What is the inheritance pattern of Peutz-Jeghers?
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AD
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What are other signs of Peutz-Jeghers?
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- Melancotic pigmentation of buccal mucosa (black/brown)
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What is the treatment of Peutz-Jeghers?
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Removal of polyps if symptomatic.
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What are juvenile polyps?
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Benign hamartomas in the small bowel and colon. Not premalignant, also known as retention polyps.
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What is Cronkite-Canada syndrome?
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Diffuse GI hamaratoma polyps (no cancer potential) associated with malabsorption/weight loss, and LOSS OF ELECTROLYTES
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What is Turcot's Syndrome?
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Colon polyps with malignant CNS tumors.
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What is diverticulosis?
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Condition in which diverticula can be found within the colon, especially the sigmoid. Usually false diverticula.
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What is the pathophysiology of a diverticulosis?
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A weakness in the bowel wall that develops at points where nutrient blood vessels enter between antimesenteric and mesenteric taeniae, increased intramural pressures then cause herniation through these areas.
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What is the incidence of diverticulosis?
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50-60% in the US by age 60. Only 10-20% become symptomatic.
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Who is at risk for diverticulitis?
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People with low fiber diets, constant constipation, and positive family history. Incidence also increases with age.
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What are symptoms/complications?
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Bleeding: may become a massive diverticulitis
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What is the treatment of diverticulitis?
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A high fiber diet is recommended..
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What are the indications for operation with diverticulosis?
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Complications (which include fistula, obstruction, stricture), recurrent episodes, hemorrhage
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When is it safe to get a colonoscopy/endoscopy in a patient with diverticulitis?
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Due to risk of perforation, this is performed 6 weeks after inflammation resolves to rule out colon cancer.
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What is diverticulitis?
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Infection or perforation of a diverticulum.
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What is the pathophisiology of diverticuliitis?
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Obstruction of diverticulum by a fecalith leads to inflammation and microperforation
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What are the signs/symptoms of diverticulitis?
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LLQ pain, diarrhea, fever, chills, anorexia
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What are the associated lab values in one with diverticulitis?
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Increased WBC
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What are the associated radiographic findings?
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On X-Ray: Ileus- Partially obstructed colon, air-fluid levels, free air if perforated
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What are the associated barium enema findings?
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Barium enema should be avoided in acute cases. (colonoscopy increases risk for perforation as well)
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What are the possible complications?
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Abscess, diffuse peritonitis, fistula, obstruction, perforation, stricture
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What is the most common fistula with diverticulitis?
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Colovesical fistula (to bladder)
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What is the best test for diverticulitis?
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CT Scan
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What is the initial therapy for diverticulitis?
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- IV fluids - NPO - Broad spectrum ABx
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When is surgery indicated for diverticulitis?
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- Obstruction - Fistula - Free perforation
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What is the lifelong risk after development of the first one?
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33% after the first, 50% after the second.
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What surgery is usually performed ELECTIVELY for recurrent bouts?
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One-stage operation: Resection of involved segment and primary anastomosis
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What type of procedure is usually performed for an ACUTE case of diverticulitis with a complication (perforation, obstruction)?
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Hartmann's procedure. Resection of involved segment with and end colostomy and stapled rectal stump
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What is the treatment for a divertucular abscess?
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Percutaneous drainage; if abscess is not amenable to percutaneous drainage, then surgical approach for drainage is necessary.
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How common is massive lower GI bleed with diverticulitis?
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VERY rare. Seen with DiverticuloSIS, not diverticulitis.
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What is the most common cause of lower massive bleeding in the lower GI in adults?
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Diverticulitis.
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What is Colonic volvus?
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The twisting of the colon about its mesentery, resulting from obstruction and if complete, vascular compromise with potential necrosis, perforation, or both.
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What is the most common type of colonic volvulus?
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Sigmoid
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What is a sigmoid volvulus?
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A twist of the sigmoid colon
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What are the etiologic factors of a volvulus??
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High residue diet resulting in bulky stools and tortuous, elongated colon, chronic constipation
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What are the signs/symptoms of a volvulus?
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- Acute abdominal pain - Abdominal distention - Obstipation - N/V
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What findings are found on an abdominal film of a volvulus?
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- Distended loop of sigmoid colon, often in the classic 'bent inner tube'
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What are the signs of necrotic bowel?
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Free air, pneumatosis (air in the bowel wall)
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How is the diagnosis of a volvulus made?
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Sigmoidoscopy or radiographic film.
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Under what condition is gastrogafin enema used?
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If sigmoidoscopy and radiographic films fail, a 'bird's beak' can be seen with a barium enema
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What are the signs of strangulation?
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- Discolored or hemorrghic mucosa on sigmoidoscopy - Bloody fluid in the rectum - Fever, hypotension, high WBCs
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What is the initial treatment of a volvulus?
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Nonoperative. If there is no strangulation, sigmoidoscopic reduction is successful in 85% of cases.
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What are the indications of surgery for a volvulus?
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Emergently if strangulation is suspected or nonoperative reduction unsuccessful (Hartmann's Procedure)
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What is a cecal volvulus?
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Twisting of the cecum upon itself and the mesentery
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What are the signs/symtoms of a cecal volvulus?
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- Acute onset of abdominal or colicky pain beginning the RLQ and progressing to a constant pain, vomiting, obstipation.
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How is the diagnosis of a cecal volvulus made?
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Abdominal plain film. Large air/fluid level, dilated, ovoid colon. COFFEE BEAN sign
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What is the treatment of a cecal volvulus?
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Emergent surgery, right colectomy with primary anastomosis or ileostomy.
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What is the MAJOR difference between a sigmoid volvulus and a cecal volvulus?
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- Cecal volvulus REQUIRES surgery - Sigmoid volvulus undergoes initial endoscopic reduction of the twist.
