CRS/SB Flashcards
What is the management of prolapse?
Surgery. Use abdominal approach for younger patients and good surgical candidates (less recurrence) and perineal approach for poor surgical candidates.
Severe intractable anal pruritus =?
Paget’s disease of the anus
How many patients with Paget’s disease of the anus have an occult malignancy?
50% have an occult internal malignancy. Therefore colonoscopy and CT should be performed. Wide local excision with multiple perianal bx is tx of choice.
Describe staging of colorectal cancer..remember, STAGING or colon and rectal cancers is the same.
Tis- confined to mucosa, doesn’t violate basement membrane
T1 - into submucosa
T2 - into muscularis propria
T3 - thru muscularis propria or into serosa
T4 - thru serosa
Stage 0: Tis, N0, M0 Stage I: T1, N0, M0 Stage II = T3 or T4 but N0 Stage IIIA: T1-2, N1 (1-3 nodes +) Stage IIIIB; T3-4, N1 Stage IIIC: any T, N2 (>3 nodes +) Stage IV: M1
What stage of rectal cancer require preop chemo-xrt?
Stage II and over
Which way does cecal volvulus point?
Toward LUQ. Common in middle aged females.
“Coffee bean sign”
Sigmoid volvulus, points up or to RUQ. Common in older patients, psychotropic meds, constipation, high fiber diet.
Treatment for sigmoid volvulus?
Endoscopic detorsion unless peritoneal (80% success) and perform sigmoidectomy during same admission (50% recur)
Treatment for cecal volvulus?
Ileocolic resection with primary anastomosis (unless threatened bowel–do end ileostomy). Don’t do pexy because of high rate of recurrence.
What are the two most common causes of lower GI bleeding?
1) bleeding diverticulae 2) neoplasia or bleeding polyps
What is the source of bleeding from a bleeding diverticuli?
Either a ruptured submucosal artery or the vasa recta.
Hinchey classification
I: paracolonic
II: abscess elsewhere (pelvis, etc)
III: purulent peritonitis
IV: fecal peritonitis
innervation of external sphincter
voluntary control, internal pudendal and S4 roots
innervation of internal anal sphincter?
involuntary, via autonomic nerve fibers
usual location of anal fissure? location that prompts further workup?
- posterior midline is usual
- lateral location should prompt Crohns, STI, or hidraadenitis workups
How does treatment of rectal cancer differ from colon cancer?
Stage II/III rectal gets neoadjuvant chemo-radiation, while colon gets surgical resection first + postop chemo, no XRT.
Cause of urinary retention after hemorrhoidectomy?
Pelvic floor muscle spasms–tx with temp foley
Most common cause of severe GI bleeding?
diverticular bleed
Describe Peutz-Jehger syndrome.
AD, characterized by intestinal hamartomas and hyperpigmented oral mucosa lesions. Colonoscopy q2 years. Increased risk of breast, cervical, thyroid, lung.
what rectal cancers can be excised transanally?
well differentiated T1 lesions, <3 cm, <30% circumference, < 8 cm from anal verge, no lymphovasc involvement or mucin production.
Treatment for c diff with sepsis or toxic megacolon?
Subtotal colectomy, ie colectomy with rectum left in place and end ileostomy
Management of intersphincteric abscess?
Internal drainage via dividing mucosa and internal sphincter
Describe Hereditary nonpolyposis CRC
Also called Lynch syndrome. AD. Tumors have high microsatellite instabiliy and defects on MLH1 and MSH2 (DNA mismatch repair). 20% risk of sporadic mutation. Need colonoscopy starting at 25 and get total proctocolectomy at first cancer operation.
Most common location of GIST?
Stomach (50%), then SB (25%)
What cell do GISTS derive from?
Interstitial cells of Cajal
What cells do carcinoid tumors derive from?
enterochromaffin cells at the base of the crypts of Leiberkuhn
5 types of hemorrhoidectomy?
open, closed, circumferential, stapled, transanal hemorrhoidal dearterialization (Doppler guided ligation of the arterial inflow of hemorrhoids)
What bacterial infections are associated with colon Ca?
Clostridium septicum, strep bovis/gallolyticus
Genes associated with colorectal ca?
APC, DCC, p53, kras
Number 1 and 2 sites of mets?
1) Liver, 2) Lung
How can rectal ca metastasize to spine?
Batson’s venous plexus
What marks transition between anal canal and rectum?
Levator ani
3 types of polyps
Hyperplastic = no cancer risk
Tubular adenoma = most common neoplastic polyp, usually pedunculated
Villous adenoma = usually sessile, 50% have cancer
Margins generally needed for colorectal cancer?
5-7 cm (ensures adequate nodal resection–need 12 nodes)
When do you need an APR?
If lesion is closer than 2 cm to levator ani muscles
Types of chemo from colorectal cancer?
5FU + oxiplatin + leucovorin=FOLFOX for 6 mos
What percentage of patients have recurrence of colorectal cancer?
20%–> need 1 yr colonoscopy
Describe Familial Adenomatous Polyposis
AD, although 20% are spontanous. All have Ca by age 40. APC gene on chromosome 5. Tx to get total proctocolectomy with J pouch at age 20 (polyps start at puberty), also need to check for duodenal polyps q2 years.
APC gene related syndromes?
FAP, Gardner (colon Ca + desmoid tumors), Turcot’s (Colon ca + brain ca)
What is the Amsterdam criteria for Lynch Syndrome?
“3,2,1” = 3 first degree relatives over 2 generations, 1 with cancer before age 50
What do you find on colonoscopy in patient with ulcerative colitis?
involves mucosa and submucosa–starts in rectum and is contiguous, has mucosal friability, pseudopolyps, and collar button ulcers
Medical tx for maintenance and flares of UC?
Maintenance: 5-ASA or sulfasalazine
Steroids for flares
Tx for infectious vs stump pouchitis?
infectious: flagyl
stump: short chain fatty acids
1 and 2 causes of colonic obstruction
1) cancer 2) diverticulitis
What percentage of patients develop a fistula after perianal abscess?
30%
Define simple vs complex fistula in ano
Simple: superficial (perianal), intersphincteric, low lying transphincteric (<30% sphincter involvement).
Complex: high transphincteric, suprasphincteric, horseshoe, recurrent
Tx for simple fistula?
If no incontinence, then primary fistulotomy and curettage.
Tx for complex fistula?
Sphincter sparing approaches 2/2 high risk of incontinence–endoanal advancement flap, modified Hanley procedure, ligation of the intersphincteric fistula tract (LIFT), diversion. Place seton FIRST.
What tx for fistula are contraindicated with incontinence?
fistulotomy, endoanal/endorectal andvancement flaps
Tx for anal cancer?
T1 lesion (well differentiated): wide local excision
Locally advanced: Nigro protocol (5-Fu, mitomycin C, 3000 Gy radiation) prior to excision and LAD
Recurrence: re-excision or APR
Workup of rectal mass?
CEA, LFTs, proctoscopy for distance from anal verge, full colonoscopy to rule out synchronous lesion,CT for mets, MRI or EUS for depth and nodal envolvement
What does colon absorb and secrete?
Absorbs: water, sodium, chloride. Secretes: bicarb + potassium. Fuel source is short chain fatty acids (butyrate, acetate, propionate).
What extracolonic manifestations of UC improve with colectomy?
Arthritis, pyoderma gangrenosum, erythema nodosum resolves, AS improves. Remember, PSC is unaffected.
What subtypes of HPV cause anal condyloma, and which can progress to dysplasia or carcinoma?
HPV 6 + 11 = condyloma
HPV 16 + 18 = more aggressive, can cause cancer
Describe characteristics of solitary rectal ulcer syndrome.
Sxs are rectal bleeding, copious mucus discharge, anorectal pain, diffuculty passing stool. Patients can have one, multiple, or no rectal ulcers. It is a benign condition. Treat conservatively first.
Describe Haggitt classification
Classification system for malignant polyps. Level 1- invade head of polyp, 2 invade neck, 3 invade stalk, 4 invade base or involve sessile polyp. Usually Haggitt 4 need segmentectomy.
Which side of the colon is most common for diverticular bleed. Which percentage of bleeds stop on their own; how many recur?
Although divertiucli are most common on LEFT side, BLEEDING from them is most common on the RIGHT. 75% of bleeding will stop, 25% will recur.
When to give blood in trauma patients, acute phase? Resusc goals?
After 2L XL. Resusc to SBP >90, LA <2.5. UOP >0.5cc/kg/hr
Most common bacteria in colon?
Bacteroides fragilis
Mechanism of diverticulitis?
obstruction of tic, leading to venous obstruction/congestion
What is management of contained anastomotic leak?
IV abx alone. Perc drain if abscess. Only operate for pelvic sepsis.
What is the treatment for recurrent anal SCC?
APR
How to handle bleeding in the first 24h following hemorrhoidectomy??
Re-explore, likely 2/2 poor suturing technique
Most common location to perforate with UC? With Crohns?
UC = transverse colon Crohn's = terminal ileum
Tx for low rectal carcinoid tumors?
If <2cm–wide local excision with negative margins. If >2 cm or invading musclaris propria then APR.
How do you dx amoebic colitis?
endoscopy shows ulceration and trophozoites. 90% of patients have anti-amebic antibodies.
What is the tx for amoebic colitis?
Flagyl, dioodohydroxyquin
Where is the primary and secondary infection of Entamoeba histolytica?
Primary = colon secondary = liver
How does actinomyces present in the colon and what is the tx?
Can be mass, abscess, fistula or induration. Path shows yellow-white sulfur granules
Tx of actinomyces in the colon?
Penicillin or tetracycline, drainage of abscess.
How long will Guiac stay + after GI bleed?
Up to 3 weeks
What rate of bleeding can arteriography detect?
> 0.5 cc/min
what rate of bleeding can tagged RBC scan detect?
> 0.1 cc/min
Why do you get uremia after GI bleed?
From bacteria eating the blood in the colon and producing more urea. Can also get elevated Tbili.
Tx for right sided diverticulitis?
right hemicolectomy
What is the best dx test for colovesicular fistula?
cystoscopy
Angiodysplasia in GI tract is assoc with what?
aortic stenosis–improves after AVR
Which areas of the colon are most vulnerable to low flow state?
Splenic flexure (Griffiths point–SMA and IMA junction) and upper rectum (Sudeck’s point–superior rectal and middle rectal artery junction)
What is neutropenic typhilitis and what is the tx?
It is an enterocolitis that occurs after chemo at the nadir of WBC. Tx is abx. Do not operate for pneumatosis, only for free perforation.
What is the venous drainage of the rectum?
Superior and middle rectal veins drain to IMV and into portal system. Inferior drains to iliac vein and into IVC.
Which patients need abx after perirectal abscess tx?
extensive cellulitis, DM, immunosuppressed, prosthetic hardware
What are anorectal problems associated with AIDS?
- Kaposi sarcoma–nodule with ulceration
- CMV- shallow ulcers, tx ganciclovir
- HSV- rectal ulcer
- B cell lymphoma- can present as abscess or ulcer
What nodes do anal margin cancers go to?
inguinal
What nodes do upper 2/3 of anal canal go to?
internal iliac
When does sloughing of eschar usually occur after hemorrhoidectomy?
After pod5
Most common location for SB lymphoma?
ileum because that is where the most lymphoid tissue is
