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Crohn Disease , UC - few dumb questions

3K views 4 replies 3 participants last post by  truepassion20 
#1 ·
Dr. Sattar in Pathoma said that we may find calcium oxalate stone in Crohn's Disease. But can we find calcium oxalate stone also in UC? Kindly exaplin.

Also he said we might find megacolon in UC. But can a patint also develop megacolon in Crohn?

Lastly, Since both the diseases inflam the mucosa, why do we get bloody diarrhea with UC? Cant any Crohn patient develop bloody diarrhea? if yes, pleas sexplain when n how??
 
#2 ·
First you have to know that how caOxalate stones are produced
> Actually There is Fat malabsorption going on and also poor enterohepatic recirculation of bile which results in fat being excreted in stool , these fats Saponify Calcium. Oxalate is usually excreted by binding to the calcium in the gut . When this Calcium has already gone out the gut in stool with the unabsorbed fats then the rest of the oxalate with no calcium to bind is absorbed more then normal eventually producing kidney stones. And it happens more profoundly in crohns because of more profound fat malabsorption and damage to ileum causing poor enterohepatic circulation of bile.

> Yes megacolon is highly specific for UC. Any patient with history of UC and an acute abdomen should be thought of Megacolon and no invasive procedure should be done because it can cause rupture of bowel (this concept is tested in uworld)

> Yes a crohns patient may or may not present with bleeding , but as far as i can recall an UC patient always have bleeding. But dont worry , they would never make you differentiate b/w both by this single presentation.
 
#3 ·
UC has ALWAYS bleeding, the affected areas are only colon and rectum. Complication are megacolon and increased risk of colorectal cancer.
In Crohn the ENTIRE GI tract can be segmentally involved, that's why in Crohn malabsorption is more common (and kidney stones - as explained in the previous post). Crohn disease has classically strictures and fistulas as complication.

You could have bleeding and megacolon in Crohn too, but rarely, and I wouldn't worry about it for the purpose of the exam!
 
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