Colon, Rectum, Anus Flashcards
Low anterior resection, which is stapled?
Mucosa, submucosa, longitudinal muscle, circular muscle
*mid and lower rectum lack serosa
Which layer of muscle joins together to form the internal anal sphincter?
Circumferential muscle layer 📌
Rectal fascia
Presacral fascia: separates the rectum from the presacral venous plxus and the pelvic nerves
WALDEYER FASCIA: rectosacral fascia; extends forward and downward and attaches to the fascia propria at the anorectal junction
DENONVILLIERS FASCIA: separates the rectum from prostate and seminal vesicles / vagina
Physiologic intesstinal herniation
At the 6th week of gestation, the midgut herniates through the abdominal cavity, rotates 270degrees counter-clockwise around thhe SUPERIOR MESENTERIC ARTERY and then travels to its resting place in the abdomine during the 10th week 📌
What happens in diversion coitis
Butyric acid and propionic acid are not being absorbed
Remarks on FOBT
- false-positive
- red meat
- some fruits and vegetables
- vitamin C
- any positive FOBT mandates further investigation, usually by colonoscopy
What workup is needed prior to ileostomy reversal
A flexible sigmoidoscopy or contrast enema to check for patency
What is the most concerning adverse outcome in end ileostomy in the short term and will require SURGICA REVISION
Stoma necrosis below the level of the fascia
Ddx for pouchitis
Bacterial or viral infection
Undiagnosed Crohn disease
Remarks on IBD
Family history: 10-30%
Remarks on ulcerative colitis
Mucosa may be atrophic, friable, with multiple peudopolyps
In long-standing UC, the colon may be FORESHORTENED and the mucosa replaced by SCAR
What structures are mot likely to be site of extracolonic disease in IBD?
Liver (m/c)
Biliary tree
Joints
Skin (erythema nodosum, pyoderma gangrenosum)
Eyes (up to 10%; uveitis, iritis, episcleritis, conjunctivitis
What is the first-line therapy for inflammatory bowel disease in the outpatient setting?
Salicylates, such as sulfasalazine and 5 acetyl salicylic acid (5-ASA)
MOA: inhibition of cyclooxygenase and 5-lipoxygenase in the gut mocosa
Case of UC: What would be inications that stoma creation would be more appropriate than a primary anastomosis?
“A prealbumin of 6.0 in a patient who has been on corticosteroids”
*in extremely malnourished patient, especially those who are also being treated with corticosteroids, creation of a stoma is often safer than a primary anastomosis
What are the mosmt common indications for surgery for Crohn’s disease?
Internal fistula or abscess (30-38%)
Obstruccctioon (35-37%)
What would indicate that a fissure is from Crohn diseaese
Deep and broad ulcer located in the lateral position (rather than anterior or posterior midline as seen in an idiopathic fissure in ano)
Remarks on diverticulitis treatment
- many surgeons now will not advise colectomy even after two documented episdoes of diverticiulitis, assuming the patient is completely ASYMPTOMATIC and that CARCINOMA HAS BEEN EXCLUDED by colonoscopy.
- IMMUNOSUPPRESSED PATIENTS are generally still advised to undergo COLECTOMY after a SINGLE episode of documented diverticulitis.
- all patients must be evaluated for malignancy via COLONOSCOPY 4-6 weeks after recolvery
- inability to exclude malignancy is another indication for resection
What are the most common fistulas that develop in complicated diverticulitis?
Colovesical fistulas
- approx 5% of patients with complicated diverticulitis deveop fistulas bet colon and an adjacent organ
- 2nd: colovaginal, 3rd: coloenteric
- colocutaneous fistulas are rare
What are the most common genetic mutations that could lead to colon cancer
APC
DCC
P53
* review K-ras, MYH 📌
Remarks on HNPCC
Lynch syndrome 1-3% of all colon cancers Mismatch repair Cancers appear in the proximal colon more often than in sporadic colon cancer and have a better prognosis regardless of stage. Amsterdam criteria is used
Mutations in HNPCC
Mutations in PMS2 or MSH6 result in a more attenuated form of HNPCC
MHS6 inactivation also appears to be associated with higher risk for endometrial cancer
Most common extracolonic malignancy in HNPCC
Endometrial cancer
Others: ovarian, pancreas, stomach
Albumin reference value (rv)
35-55 g/L
3.5-5.5 g/dL
Prealbumin rv
0.1-0.4 g/L
(0.01-0.04 g/dL)
(10-40 mg/dL)
*indicator of nutritinon,
*binds thyroid hormone and retinol binding protein
