Mehlman. IBD 03-04 (3) Flashcards
IBD refers to both ulcerative colitis (UC) and Crohn.
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Both can present with bloody, mucoid stools
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Both are associated with HLA-B27 –> PAIR –> Psoriasis, Ankylosing spondylitis, IBD, Reactive arthritis.
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For example, if a patient has psoriasis + bloody stools, you say, “The bloody stools are probably …….
IBD
Or likewise, if patient with known IBD has lower back pain that’s worse in the morning, you say, “that’s
probably …..
ankylosing spondylitis.
Both UC and Crohn can be associated with other ….
autoimmune diseases UNRELATED to HLA-B27, like vitiligo
Both can cause anterior uveitis (non-specific finding seen in many autoimmune diseases).
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Both have risk of colon cancer if the colon is involved. but which one has higher risk?
But if you’re forced to choose, UC has > risk than
Crohn because the colon is always involved in UC but not always in Crohn
both are treated with what?
Both are treated with 5-ASA NSAID compounds (mesalamine / sulfasalazine) or steroids.
If they ask first
Tx, go with …….?
If they ask first
Tx, go with mesalamine or sulfasalazine, whichever they list (they won’t list both) over steroids.
USMLE wants you to know ….. are used in IBD in patients who fail initial Tx with 5-ASAs and steroids.
anti-TNF-a agents (i.e., infliximab, adalimumab, etanercept)
Q on 2CK IM form 8 has “prednisone therapy” as answer for Crohn, but a 5-ASA isn’t listed.
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f they ask you for which cytokine can be anti-inflammatory for IBD, the answer is …..
IL-10.
Sounds weird, but
just know IL-10 and TGF-b are mostly anti-inflammatory mediators. Don’t worry about Th1 vs Th2 nonsense.
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UC - rectum-ascending.
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UC - what extent?
Not transmural – i.e., only affects mucosa and submucosa.
UC can be fistula?
fistulae are not seen. If they say fistulae to the skin overlying the anus or to any organ,
this means transmural involvement (Crohn).
UC what shows colonoscopy?
Colonoscopy will show pseudopolyps and crypt abscesses. You don’t need to
know what these look like. You just need to know they = UC.
UC what shows barium enema?
Barium enema shows “lead-pipe appearance” due to loss of haustra. This detail is very important for UC.
vaizdas tiesiog kaip vamzdis
UC with what autoimmune assoc?
Can cause primary sclerosing cholangitis, as discussed earlier. This can be associated with pANCA antibodies
What skin lesion can present in patients with UC?
Pyoderma gangrenosum is a necrotic skin lesion seen rarely in patients with UC.
There is an NBME Q that describes this as an “ulcer with necrotic debris.”
UC. what colon pathology can cause?
Can cause toxic megacolon, which presents as SIRS and sometimes low BP in a patient with UC. They might say abdominal x-ray shows a 12-cm cecum (NR 3-8).
UC. If patient has toxic megacolon + stable –> Tx?
If the patient has normal BP, NBME for 2CK wants steroids first for toxic
megacolon.
UC. If patient has toxic megacolon + UNstable –> Tx?
If the patient is unstable, go straight to laparotomy.
UC. Colectomy is sometimes performed in patients with severe UC, but very rarely in
Crohn
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Crohn. extension?
“Mouth to anus” – i.e., can occur anywhere in GI tract. USMLE loves giving
mouth ulcers in Crohn. But terminal ileum is highest yield location
Crohn. HY location?
But terminal ileum is highest yield location.
Crohn. whats about fistula?
Transmural – i.e., can cause anal fistulae + to other organs.
Crohn. what shows colonoscopy?
Colonoscopy shows skip lesions, where there is alternating diseased vs normal bowel segments, with cobblestone ulcers.
Crohn.
“Creeping fat” is buzzy term that can be seen on NBME, which refers to intestinal fat migration that wraps around the bowel
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Crohn. what barium enema shows?
Barium enema shows “string sign,” where inflamed segments are narrowed in
comparison to normal bowel.
Crohn. biopsy?
Biopsy shows non-caseating granulomas. Very HY for USMLE you know that Crohn + sarcoidosis both have non-caseating granulomas.
Crohn.
Sometimes associated with erythema nodosum. Not specific for Crohn in any regard, but tends to have association, whereas UC is pyoderma gangrenosum.
!!!!!! SKIRTUMAS!!!!!!!
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Crohn = erythema nodosum
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UC = pyoderma gangrenosum.
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Crohn. keistas pirma kart girdetas dalykas.
Can cause anti-saccharomyces cerevisiae (yeast) antibodies. This is on a 2CK NBME, where they say (-) for these Abs, but (+) for pANCA, where answer is UC.
Crohn. Intestinal malabsorbtion?
Intestinal malabsorption can occur, resulting in B12 deficiency most commonly due to terminal ileum being classic inflammatory location
Crohn. What kidney?
Impaired fat absorption can result in calcium oxalate urolithiasis, as discussed in the HY Renal PDF.
