Colon and Rectum Flashcards
Lateral peritoneal reflections of the ascending and descending colon
White lines of Toldt
What parts of the GI tract do not have a serosa
Esophagus
Middle and distal rectum
What are the major anatomic differences between the colon and the small bowel
Colon has teniae coli, haustra, and fat appendages; whereas, the small intestine is smooth
Identify A, B, and C
A = Superior mesenteric artery
B = Inferior mesenteric artery
C = Ileocolic artery
How are tumors staged
TMN staging system
What are the common preoperative IV antibiotics
Cefoxitin (Mefoxin), carbapenem*
What decides low anterior resection (LAR) versus abdominal perineal resection (APR)
Distance from the anal verge, pelvis size
Why is follow-up so important the first 3 postoperative years
90% of colorectal recurrences are within 3 years of surgery
Tissue growth into the bowel lumen, usually consisting of mucosa, submucosa, or both
Rectal polyps
How are polyps classified
Sessile (flat)
Pedunculated (on a stalk)
Where are most polyps found
Rectosigmoid (30%)
Condition in which diverticula can be found within the colon
Diverticulosis
What is the most common site for diverticulosis
95% of people with diverticulosis have sigmoid colon involvement
What are the associated lab findings with diverticulitis
Increased WBC
Is a colonoscopy safe in an acute diverticulitis setting
No - increased risk of perforation
What the most common fistula with diverticulitis
Colovesical fistula (to bladder)
What is the best test for diverticulitis
CT scan
What is the most common carcinoma of the anus
Squamous cell carcinoma (80%)
(think - ASS = Anal Squamous Superior)
Anal fistula from rectum to perianal skin
Fistula in Ano
Thick suture placed through fistula tract to allow slow transection of sphincter muscle
Seton
Abscess formation around the anus/rectum
Perirectal abscess
Tear of fissure in the anal epithelium
Anal Fissure
What is the “rule of 90s” for anal fissures
90% occur posterior
90% heal with medical treatment
90% of patients heal successfully
Engorgement of the venous plexuses of the rectum, anus, or both with protrusion of the mucosa, anal margin, or both
Hemorrhoids
What condition is a contraindication for hemorrhoidectomy
Crohn’s disease
What must be ruled out with lower GI bleeding believed to be caused by hemorrhoids
Conon cancer (colonoscopy)
Bleeding distal to the ligament of Treitz, vast majority occurs in the colon
Lower GI bleeding
