Chapter 12, part 3 Flashcards Preview

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Flashcards in Chapter 12, part 3 Deck (67):
1

Pseudomembranous colitis

Overgrowth of C. diff (happens after abx use)

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Transmission of pseudomembranous colitis

Fecal oral route

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What are the two endotoxins that C. diff produces?

Enterotoxin
Cytotoxin
Cause mucosal damage resulting in exudative pseudomembrane on scope

4

Dx of pseudomembranous colitis

ELISA (and PCR if necessary)
GDH

5

Tx of pseudomembranous colitis

Initial: oral metronidazole or oral vanc (chosen in more severe cases)
In the case of septic shock, subtotal colectomy with end ileostomy

6

Causes of bloody diarrhea

Shigella
C. jejuni
Enterohemorrhagic E. coli (EHEC)
E. histolytica
Certain salmonella

7

E. histolytica and bloody diarrhea

Causes amebic colitis

8

Amoebic colitis sx

Mimics IBD (crampy abd pain and bloody diarrhea)

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Dx of amoebic colitis

Stool studies
Antigen testing
Endoscopy (ulcerations and trophozites)

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Tx of amoebic colitis

Metronidazole + luminal agent (paromomycin)

11

Shigella and bloody diarrhea

Fecal-oral route or through contaminate food and water

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Dx of shigella

Stool culture

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Tx of shigella

Self-limiting, but can give FQ to reduce duration

14

EHEC

Fecal contamination of foods

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MC sx of EHEC diarrhea

Hemorrhagic colitis

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Tx of EHEC

Supportive

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What is a major potential sequela of EHEC infection?

HUS (hemolytic uremic syndrome)
5-10 days after diarrhea
Acute renal failure, thrombocytopenia, and microangiopathic hemolytic anemia

18

Salmonella

Gastroenteritis caused by nontyphoidal strains= MC

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Sx of salmonella bloody diarrhea

Abdominal pain
Fever
Vomiting 1-3 days after exposure

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Tx of salmonella bloody diarrhea

Self-limiting, supportive

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C. jejuni

Same sx and tx as salmonella

22

Cytomegaloviral colitis

Presents similar to appendicitis (tx with ganciclovir)

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Neutropathic enterocolitis

MC affects cecum
Immunosuppressed pts undergoing chemo
Presents like appendicitis
Tx: bowel rest and IV abx

24

What is the MC site of bowel ischemia and why?

Colon
Usually d/t prolonged hypoperfusion secondary to hemodynamic instability

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What is the MC site of the colon for ischemia

Watershed areas (splenic flexure)

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S/sx of ischemia of the colon

Worsening abdominal pain (out of proportion to the exam)
Bloody diarrhea
Abdominal distention

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Lab findings for ischemia of the colon

Lactic acidosis
Leukocytosis

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Rads for ischemia of the colon

CT:
Bowel wall edema or pneumatosis of intestinal wall
Sigmoidoscopy or colonoscopy:
Patchy hemorrhagic areas with dusky mucosa

29

Tx of ischemia of the colon

If full thickness necrosis or perforation: urgent segmental resection and creation of stroma
Partial thickeness: abx, bowel rest, and correction of hypoperfused state

30

Where can Crohn's be found?

Anywhere in GI tract (mouth to anus)
Terminal ileum is MC

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What type of involvement occurs in Crohn's?

Patchy involvement

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What components does Crohn's affect?

Transmural inflammation

33

Gross appearance of Crohn's

Segments look grossly inflammed with thickened mesentery and creeping serosal fat

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What is seen on colonoscopy in Crohn's?

Long longitudinal ulcers and erosions of the submucosa: cobblestoning

35

Path of Crohn's

Transmural infiltration with deep penetrating fissures through muscularis propria and non-caseating granulomas

36

Presentation of Crohn's

Crampy abdomainl pain
Diarrhea +/- bleeding
Fever
Weight loss

37

Dx of Crohn's

Colonscopy and imaging of the small bowel
Granulomas on hx
Colonscopy q1-2 yrs beginning 10 years after dx

38

Tx of Crohn's

Sulfasalazine, immunosuppresives and biologics
Pts with highly symptomatic focal dz may benefit from early interventions
Fulminent colitis (doesn't respond to therapy in 5-6 days): total abdominal colectomy and end ileostomy
Total proctocolectomy is contraindicated in Crohn's
If obstructive sx present: surgery is recommended

39

What are the hallmark of Crohn's?

Fistulas: 1/3 will develop internal fistula = SB to SB or SB to colon

40

Enterocutaneous fistulas in Crohn's

Low output <500 mL/day
High output >500 mL/day
Bowel rest, TPN and aggressive tx of the Crohn's
Refractory: operation and resection

41

Where can UC be found?

Rectum and progresses proximally (does not involve the small bowel)

42

What type of involvement occurs in UC?

Contiguous

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What components does UC affect?

Only affects the mucosa

44

Gross appearance of UC

Nl

45

Colonoscopy findings of UC

Extremely friable mucosa

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Path of UC

Nl muscularis propria

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Presentation of UC

Frequent bloody diarrhea
Crampy abd pain
Tenesmus and urgency resulting in fecal incontinence

48

Dx of UC

Stool studies for ova and parasites
Stool cultures
Colonoscopy and hx

49

Extracolonic fistulas and UC

Pyoderma gangrenosum- destructive inflammatory ulcerative dz of the skin commonly found around ostomy sites
Primary sclerosing cholangitis: obliterating inflammatory dz of the small and large bile ducts = MC noninfectious indication for liver transplant

50

Tx of UC

Moderate dz: sulfasalazine
Severe cases: azathioprine and 6-mercaptopurine
-Steroids during exacerbation
Surgery fro those pts refractory to meds= MC indication

51

What is the risk of UC pts having colon CA?

33% lifetime risk
Colonoscopy starting 10 yrs after dx

52

What cures UC?

Surgical therapy at removing all mucosa
Total proctocolectomy with ileal pouch and anastamosis

53

Total proctocolectomy with IPAA

Entire colon and rectum mobilized and removed
J. pouch constructed using the terminal ileum
Pouch anastamosed to the remnant of the distal rectum and anus
Temporary diverting loop ileostomy may be done
May do rectal mucosectomy to remove remaining mucosa

54

What is the 3rd MC cancer in the US?

Colorectal

55

Adenocarcinoma

Adenoma leads to dysplasia leads to invasive carcinoma

56

What is the MC neoplastic polyp?

Adenoma
Precursor for all colorectal CA

57

Adenoma

Can be pedunculated or sessile (no stalk, so automatically level 4)
Tubular, villous, tubovillous
If they are >2 cm, villous, and sessile: higher risk of CA

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Hagitt criteria level 0

Carcinoma in situ. No invasion

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Hagitt criteria level 1

Head of polyp

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Hagitt criteria level 2

Head + neck of polyp at junction of adenoma and stalk

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Hagitt criteria level 3

Into the stalk

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Hagitt criteria level 4

Into submucosa of bowel but above muscularis propria

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Tx of malignancies

Polypectomy if malignancy well differentiated
May need resection if not defined lesions

64

What are the MC neoplasms?

Benign
Classified into hyperplastic, juvenile, and inflammatory

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Parameters of benign neoplasms

<3 mm
No malignant potential

66

Juvenile polyp

Hamartomas seen throughout the GI tract
Associated with polyposis syndromes, no malignant potential, but often bleed

67

Inflammatory polyp

Result from repetitive mucosal ulceration and regeneration