Gastroenterology

Question 1

Give the formula for stool osmotic gap

Answer 1

Osmotic Gap = Measured Osmolality - 2*(Na + K)

If <75, possible secretory laxative

If >75, measure fecal fat and rule out use of lactulose, sorbitol, mineral oil, magnesium sulfate, polyethylene glycol

Question 2

Give clinical presentation, pathology findings, and associated symptoms of Primary Sclerosing Cholangitis

Answer 2

Jaundice, fatigue, pruritus

Multifocal narrowing and dilation of both intrahepatic and extrahepatic bile ducts

Bx with lymphocytic infiltration and péridural onion-skin fibrosis

Associated with underlying IBD, recommend colonoscopy in all newly diagnosed patients

Txt are bring things open, transplant