{"type":"rich","version":"1.0","provider_name":"Transistor","provider_url":"https://transistor.fm","author_name":"Board Pearls","title":"Chapter 12, Ep 2 of 2: BAM Microscopic Obscure","html":"","width":"100%","height":180,"duration":707,"description":"Episode two of the Chronic Diarrhea and Malabsorption chapter works the patient who arrives after a clean standard workup. Three entities account for most of what the first pass missed: bile acid malabsorption, microscopic colitis, and a structured algorithm for obscure chronic diarrhea. Board-tested reasoning on typing, testing, and the trials that are diagnostic and therapeutic in one step.\n \nTopics covered\n\nBile acid malabsorption\nCamilleri classification\nHundred-centimeter ileal resection rule\nPost-cholecystectomy diarrhea\nMicroscopic colitis\nLymphocytic vs collagenous colitis\nObscure chronic diarrhea algorithm\nIBS-D overlap\n \n \nKey decisions\n\nUnder 100 cm of resected ileum, cholestyramine fixes bile acid diarrhea; over 100 cm the picture flips to steatorrhea and cholestyramine worsens it, so use medium-chain triglycerides plus a low-fat diet.\nIdiopathic (type 2) bile acid diarrhea hides inside the IBS-D label; low fasting FGF19 and elevated C4 are the serum surrogates, and an empiric sequestrant trial responding within a week or two confirms it in the US where the SeHCAT scan is unavailable.\nMicroscopic colitis is diagnosed only on random biopsies from at least the right and left colon; lymphocytic colitis needs more than 20 intraepithelial lymphocytes per 100 surface cells, collagenous colitis a subepithelial band over 10 microns, both with preserved crypt architecture.\nFirst therapeutic move in microscopic colitis is removing the offending drug (NSAIDs, PPIs especially lansoprazole, SSRIs) and smoking cessation; budesonide six to eight weeks is first-line for moderate to severe disease.\nA celiac patient with persistent watery diarrhea on a strict gluten-free diet needs colonoscopy with random biopsies, not a repeat duodenal biopsy, because microscopic colitis is far more common in celiac.\nObscure diarrhea is worked in prevalence order: sequestrant, then rifaximin, then lactose-free, then low-FODMAP, then pancreatic enzymes, with HLA testing to exclude...","thumbnail_url":"https://img.transistorcdn.com/-FuAdDBcPDLhEoUmroZKtOBRvuBn_FHPpYlh41hOnU4/rs:fill:0:0:1/w:400/h:400/q:60/mb:500000/aHR0cHM6Ly9pbWct/dXBsb2FkLXByb2R1/Y3Rpb24udHJhbnNp/c3Rvci5mbS9iNzlh/ZTU4Y2MzNWExMjQ5/MjA5OWMwMmI3ZTk5/NGFiZS5wbmc.webp","thumbnail_width":300,"thumbnail_height":300}