o Presents with abdominal pain and bloody diarrhea that is chronic
o Problem starts in the rectum and spreads proximally (backwash ileitis)
o Pathology reveals superficial ulcers with crypt abscesses
o Some common extra-intestinal manifestations include:
Aphthous ulcers
Pyoderma gangrenosum
Primary sclerosing cholangitis
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Ankylosing spondylitis
Arthritis (mirrors Ulcerative Colitis)
Erythema nodosum (mirrors Ulcerative Colitis)
o Can show positive p-ANCA on labwork
o Colonoscopy should be performed 8 years after diagnosis and then every 1-2
years afterwards as patients with UC have an increased risk of colon cancer
If dysplasia is seen on colonoscopy, total proctocolectomy should be
performed
Crohn’s Disease
o Rectum is spared with Crohn’s Disease. Crohn’s Disease occurs mainly in the
terminal ileum (Skip lesions are common)
o Common presentation is right lower quadrant mass, weight loss, and diarrhea
(can be bloody but can also be watery)
o Pathology will show deep ulcers with granuloma formation
o Not as common to see extra-intestinal manifestations with Crohn’s Disease as
is seen in patient with UC
o Colon cancer can occur but is more common in UC patients
o Can show positive ASCA (anti-Saccharomyces Cerevisiae antibodies) on
labwork
o Colonoscopy should be performed 8 years after diagnosis and then every 1-2
years
If dysplasia is seen on colonoscopy, total protocolectomy should be
performed
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Gastroenterology Pearls: Digestive Tract in 7 Major Parts
By: Dr. Ruchi Bhatia
As previously mentioned, the Gastroenterology and Hepatology section of the ABIM Internal
Medicine exam comprises of about 9% of the entire exam - that means out of 240 total questions (4 sections of 60 questions each), we can expect about 20 questions to be geared
towards our liver and GI tract. For the Internal Medicine Shelf Exam, Gastroenterology comprises 7-13% of the exam.
Overall, the digestive system is fascinating (the liver itself is the largest organ in the body and
performs over 500 functions!) yet quite simple (think of it this way – food goes in to the mouth,
down the esophagus and in to the stomach, through 26 feet of small intestine in to the colon.
Then out.)
To simplify for the ABIM exam, let’s divide the digestive tract in to 7 major parts and discuss
a couple important topics in each – Esophagus, Stomach, Pancreas, Biliary Tract, Small
Bowel, Colon, and Liver.