Large Bowel Flashcards by Michael Cheng

Fuel used by colonocytes? Clinical significance?

short chain fatty acids (eg butyric acid, acetate, propionate) - significant because their use is first line treatment (as rectal enema) for diversion colitis

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What is the arc of Riolan?

short direct connection between the SMA and the IMA

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What is Griffith’s point? Sudak’s point?

Griffith’s = splenic flexure (Griffith park = higher) between SMA and IMA; Sudak’s = rectum between superior rectal and middle rectal junction

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What are Meissner’s and Auerbach’s plexus?

Meissner is inner (M for middle)< Auerbach is outer (sounds like “auter”)

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What is denovilliers fascia? Waldeyer’s fascia?

Denovilliers fascia is anterior (rectovesicular fascia or rectovaginal), Waldeyer’s is the rectosacral fascia (posterior)

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Rectal cancer with spinal mets?

Metastasize via Batson’s plexus (venous)

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Components of FOLFOX

5FU, leucovorin, oxaliplatin

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Gene for FAP?

APC gene - chromosome 5q - autosomal dominant

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What is Gardner’s syndrome?

APC gene / colon Ca + desmoid tumors / osteomas

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What is Turcot’s syndrome?

APC gene / cvolon Ca + brain tumors

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Gene for HNPCC?

DNA mismatch repair gene, autosomal dominant

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Amsterdam criteria for Lynch syndrome? Modified Amsterdam criteria?

“3 , 2, 1, 1” = at least 3 relatives with histologically verified cancers of colon, endometrium, small intestine, or pelvi; over 2 generations, 1 with cancer before age 50, 1 should be a first degree relative of the other two – FAP must also be ruled out

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What are the Hinchey classifications? Definition of complicated diverticulitis?

I confined abscess, II distant/retroperitoneal abscess, III purulent peritonitis, IV feculent peritonitis - complicated diverticulitis includes free perforation, abscess, fistula, obstruction, stricture

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Stercoral ulcers: locations? Risk factors?

Hard fecaloma leading to local ischemia, ulcer formation and perforation - antimesenteric border of rectosigmoid colon most likely location, associated w/ elderly patients w/ chronic constipation, assoc. w/ NSAIDs and anticholinergic agents

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Non-surgical treatment for Ogilvie’s syndrome

In stable pt without bowel compromise; bowel rest, NG tube suction, decompressive rectal tube, electrolyte repletion, consider neostigmine (80-90% successful) - contraindications include acute urinary retention, acute coronary artery syndrome, asthma, bronchospasm, 2nd/3rd degree heart block; need to be in cardiac monitoring w/ atropine ready

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Surgical management of Ogilvie’s syndrome

1) tube colostomy “blow hole”, 2) transanal insertion of long multiperforated drainage tube and 3) total/subtotal colectomy w/ ostomy

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CRC screening guidelines

Pt w/o IBD/family hx should start at age 50 or presentation w/ worrisome symptoms, w/ FHX begin screening 10 yrs prior to age of dx of any 1st degree relative w/ CRC

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Ileoanal pouch creation - diarrhea, hematochezia, abdominal pain, fever, malaise; dx, tx

endoscopy w/ biopsy (to r/o Crohns dz), histology, tx w/ cipro (more effective than flagyl), otherwise salicylates, stool enemas, probiotics

Screening recommendation for FAP?

1st degree releatives of FAP patients who are APC positive should begin screening at age 10-12 w/ flex sigmoidoscopy, upper endoscopy for surveillance every 1-3 years starting at age 25-30 for periampullary carcinoma

Treatment of choice for pt w/ UC and high grade dysplasia seen in the sigmoid colon?

Restorative proctocolectomy with ileal pouch-anal anastomosis

Earliest finding of Crohn’s disease on endoscopy?

Mucosal edema -> friable mucosa -> ulcerations

Familial juvenile polyposis - genetics, polyp types, risk of colon ca, surveillance, surg mgmt

autosomal dominant (similar to HNPCC, FAP, Peutz-Jegher), polyps are hamartomas (not adenomas) however can degenerate into adenomas and malignancy; lifetime risk of colon ca is 10-38%; colonoscopic surveillance recommended beginning at age 10-12; do polypectomy, if adenomatous changes, than proceed with colectomy

Treatment of C. diff infection? Recurrent C. diff infection?

oral metronidazole for 10-14 days - 1st recurrence treated with repeat 10-14 day course, 2nd recurrence treated with oral vancomycin

tympanic mass LUQ, XR showed dilated loop of bowel with haustral markings from RLQ to LUQ - dx (types), tx?

cecal volvulus; occurs in younger pts, axial ileocolic volvulus (90% cecum rotates up and over to the LUQ), cecal bascule (10% cecum flips upwards/anterior in a horizontal plane) - tx w/ R hemicolectomy w/ primary anastomosis (vs ostomy if evidence of gangrenous colon); high recurrence rates w/ detorsion/cecopexy, unable to be tx w/ endoscopy

40M w/ 5 day of RLQ pain, anorexia and fever, focally tender in RLQ with palpable mass - tx?

acute appendicitis, palpable mass suggests perforation/walled off abscess -> best managed with non-op therapy IV abx/bowel rest (DeVirgilio)

Management of iatrogenic and symptomatic colon perforation?

Primary repair -- resection and colostomy reserved for pt w/ long standing perforation and diffuse fecal contamination

role of chemotherapy in colon cancer? stage 1? 2? 3? 4?

stage 1 (node negative, invades submucosa) colon ca does not need chemo, stage 2 (node negative, invades subserosa or invasion of adj organ) remains debatable, stage 3 combo of 5 FU and leucovorin prolongs survival in stage 3 (+lymph nodes, no distant mets) but not stage 4

Pt w/ positive APC gene, sigmoidoscopy shows 8 adenomatous polyps, management?

total proctocolectomy - ideally w/ ileal pouch anal anastamosis - total abdominal colectomy w/ ileorectal anastomosis is another option, requires lifelong surveillance of rectum -- ileostomy last option

Most common perianal lesion in Crohn's disease?

Skin tag > fissures. Also higher risk for hemorrhoids, perianal abscess/fistula

Explain periumbilical / RLQ pain in appendicitis

Distention of appendix stretches surrounding visceral peritoneum, stimulating its afferent fibers leading to the dull periumbilical pain that later becomes RLQ pain as the localized somatic fibers of the parietal peritoneum are stimulated

Most common cause of rectovaginal fistula?

Obstetric injury > Crohn's

Immune function of the appendix?

Secretes IgA

What is an Amyand hernia?

Hernia containing an appendix

35M w/ 1 day of anorexia, RLQ pain, tenderness and low grade fever. At surgery appendix is normal, cecum and TI are red and inflamed. Management?

Crohn's terminal ileitis -> close, schedule for colonoscopy. No appendectomy given inflamed cecum, otherwise appendectomy to avoid confusion in future

Appendicitis in HIV pt - incidence? Presentation? Labs? Risk of perforation? Morbidity?

Higher incidence compared to regular population, can have atypical symptoms, may not have absolute leukocytosis (but have a relative leukocytosis), higher risk of perforation, similar morbidity in non-perforated cases, higher risk in perforated cases

most common worldwide intestinal parasite associated with appendicitis?

ascaris lumbricoides

strongyloides stercoralis is associated with...

pneumonitis, malabsorption, bleeding ulcers

clonorchis sinesis is associated with...

pigmented gallstones and cholangiocarcinoma

acute mesenteric adenitis: bacterial associations, lab/imaging findings vs appendicitis

assoc. with yersinia enterocolitica, helicobacter jejuni, campylobacter jejuni, salmonella/shigella, strep infections of pharynx, more common in children, often preceded by URI -- exam is more vague/diffuse tenderness w/o guarding, no localized tenderness; leukocytosis similar (10-15), CT shows generalized lymphadenopathy in the small bowel mesentery

most common cause of pseudomyxoma peritonei?

benign mucinous cystadenoma

surgical management of appendiceal carcinoid?

tumors >2 cm at the tip or >1 cm with extension into mesoappendix or base proceed w/ right colectomy

Screening recommendation for HNPCC?

colonoscopy starting at age 25 (or 10 yrs less than age of family member w/ CRC) - more commonly R sided

Where is the majority of water reabsorbed in the body? How does the colon reabsorb water?

Small bowel (more than colon), sodium reabsorbed actively via NaK-ATPase with water following passively, chloride actively absorbed via chloride-bicarb exchange

T N M staging for colorectal cancer?

T1 submucosa, T2 muscularis propria, T3 serosa/through muscularis propia, T4 through serosa or into adjacent organs/structure; N1 1-3 nodes, N2 >4 nodes, N3 central nodes positive, M1 distant mets