Stones in Crohn's disease

Hello everyone, 

In this post, I'll be talking about the different types of stones seen in Crohn's disease. Let's learn why they form! 

CHOLESTEROL GALLSTONES: Either due to ileal involvement or ileostomy, in Crohn's, enterohepatic circulation of bile acids is perturbed resulting in supersaturation of bile with the cholesterol, altering the delicate composition of bile acids, phospholipids, and cholesterol of 10:3:1 in bile fluid.

CALCIUM BILIRUBINATE GALLSTONES: Due to alteration in colonic flora conjugated bilirubin is converted to unconjugated bilirubin, which along with seepage of excessive unabsorbed bile acids from the ileum, results in enhanced absorption of bilirubin from the colon causing increased concentration in bile.

CALCIUM OXALATE RENAL STONES:

Usually, calcium in the GI tract forms a complex with oxalate ions resulting in its excretion in stool but in Crohn's due to steatorrhea excessive unabsorbed negatively charged fatty acids bind with calcium, leaving unbound oxalate to be absorbed and subsequently excreted by urine causing nephrolithiasis.

URIC ACID RENAL STONES: Diarrhea in Crohn's causes metabolic acidosis due to decreased bicarbonate absorption or increased excretion from the colon which increases the acidity of tubular fluid. The increased acidity, simultaneous dehydration, hypocitraturia, and hypomagnesemia in such patients precipitate uric acid stones.

-Kirtan Patolia