Why does duodenal switch surgery cause kidney stones

Looking around I find Clematis ( fellow poster) points to an answer



It's a difficult read, but in essence the author takes apart a study on RNY pre and post surgery..

I think this will apply to DS as well because the underlying physiology, delivery of undigested fat to the large colon, is similar

Most interesting thing I found was urine oxalate( which tracks with kidney stones) is less sensitive to diet than before... the big driver is diet fat... go figure... we ( DS) should all be on low fat diets

I'll let the author speak for himself


"At issue is malabsorption of diet fat. The bariatric procedures indeed cause this, variably, and the delivery of extra fat into the colon is thought to cause undue absorption of diet oxalate. Sans colon, no humans develop hyperoxaluria from bowel malabsorption. But to understand the role of fat, we have to grapple with just what diet oxalate and urine oxalate values were before and after surgery.

"An emphasis on diet fat, and on fat malabsorption, is not arbitrary. As this paper mentions in its background, the ruling theory of how malabsorption causes stones is via increase of urine oxalate, and the theory of how oxalate rises is via increased fat delivery to colon with consequent increase of colon oxalate absorption.


~~~~~ recommendations
Urine Volume
Urine volume needs to be above 2.5 liters/d as in any stone former. If I can achieve it, I will. When restrictive surgery limits fluids, constant sipping is a realistic alternative.

Urine Citrate
I see no reason to omit potassium citrate supplements if urine citrate is below the stone risk threshold of 450 mg/d and the alternative of more fruits and veggies fails to work given the altered bowel function.

Diet Oxalate
Obese patients with stones seem to have high urine oxalate at least in part from high diet oxalate intake. >>>>~After surgery the effect of diet pales compared to effects of fat,<<<<<< but as I mentioned above the goal of less than 150 mg/d of diet oxalate is reasonable.

Diet Calcium
Given hyperoxaluria – very likely – I try to use high calcium foods as I do in all cases, timing them with larger meals or meals that will contain appreciable oxalate. If food calcium is not possible I use supplements timed in the same manner. Diet oxalate is best below 100 mg/d if that permits adequate intake of fruits and veggies.

Diet Fat
Diet fat is as important after surgery, as unimportant before surgery. That is a remarkable lessen from a wonderful research article I spent a lot of your reading time on. Diet fat reduction depends upon general nutrition. When possible I aim for it.
 
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It's a difficult read, but in essence the author takes apart a study on RNY pre and post surgery..

I think this will apply to DS as well because the underlying physiology, delivery of undigested fat to the large colon, is similar

Most interesting thing I found was urine oxalate( which tracks with kidney stones) is less sensitive to diet than before... the big driver is diet fat... go figure... we ( DS) should all be on low fat diets
However, RNYERS loss the ability to malabsorb food about 2-5 years out. The only thing they permanently malabsorb is vitamins. Trying to correlate RNY results to DS results is like comparing apples to oranges. Both are fruits, grow on trees, and have seeds but that’s about the end of their similarities.

Low fat for a DSer is way different than for normal humans. If I ate low fat, I’d end up with colorectal surgery.

And while we are obsessed here with our innards, honestly most DSers don’t have issues with kidney stones. The ones who do are very vocal.
 
However, RNYERS loss the ability to malabsorb food about 2-5 years out. The only thing they permanently malabsorb is vitamins. Trying to correlate RNY results to DS results is like comparing apples to oranges. Both are fruits, grow on trees, and have seeds but that’s about the end of their similarities.

Low fat for a DSer is way different than for normal humans. If I ate low fat, I’d end up with colorectal surgery.

And while we are obsessed here with our innards, honestly most DSers don’t have issues with kidney stones. The ones who do are very vocal.


Ok... I'll buy that... I really have no experience other than what I read. In the general literature there are people who form stones and people who do not. In this small study, post RNY, oxalate content increased with meal fat content

Great... one less thing to worry about.
 
I know personally about 20 DSers total. I know 1 with kidney issues and that's it. You also have to remember many of us, including me, are getting older! If I compare people I know with kidney problems, most did not have a DS. I think we tend to blame the DS for everything just because it's there!
 
I must travel with a different crowd, I only know one women who has had bariatric surgery,RNY, and that's because she worked with my wife.

Off topic, but how did you meet so many people who had DS?
 
I must travel with a different crowd, I only know one women who has had bariatric surgery,RNY, and that's because she worked with my wife.

Off topic, but how did you meet so many people who had DS?
On the boards for 20 years.... Also met about 8 DSers in Spain.
 
Vocal DSer here! My urologist says that stones are not uncommon w/bariatric surgery.

HOWEVER, my weirdness is MY weirdness and it exists in addition to the NORMAL bariatric stuff.

To wit...I seem to have an underlying kidney issue which is PROBABLY exacerbated by my malabsorption of calcium. And, cuz I’m so cute, I have a LEFT KIDNEY PROBLEM...not a systemic issue, which it would be if it were all the fault of the DS. I keep growing mega-stones in my left kidney and none in my right kidney. So, it’s almost all geography, barely any chemistry.

Which means...I had a ureterscopy w/laser blasting and all in Jan 2018, and he got them all...but by May of 2019, I needed a repeat, and he got them all...but it’s November and I have another 7mm stone...in just six months.

Our current plan? Have another ultrasound in Feb. If it’s still 7mm, we wait and watch. If it’s bigger, we go in again.

As an aside...my urologist, bariatric surgeon and GI doctor are all Armenian. So today, at the uro’s, I said that I thought it was notable that I have three Armenian doctors who don’t want me anywhere near their grape leaves. Uro said, “No! You have three Armenian doctors telling you to eat meat!”
 
Vocal DSer here! My urologist says that stones are not uncommon w/bariatric surgery.

HOWEVER, my weirdness is MY weirdness and it exists in addition to the NORMAL bariatric stuff.

To wit...I seem to have an underlying kidney issue which is PROBABLY exacerbated by my malabsorption of calcium. And, cuz I’m so cute, I have a LEFT KIDNEY PROBLEM...not a systemic issue, which it would be if it were all the fault of the DS. I keep growing mega-stones in my left kidney and none in my right kidney. So, it’s almost all geography, barely any chemistry.

Which means...I had a ureterscopy w/laser blasting and all in Jan 2018, and he got them all...but by May of 2019, I needed a repeat, and he got them all...but it’s November and I have another 7mm stone...in just six months.

Our current plan? Have another ultrasound in Feb. If it’s still 7mm, we wait and watch. If it’s bigger, we go in again.

As an aside...my urologist, bariatric surgeon and GI doctor are all Armenian. So today, at the uro’s, I said that I thought it was notable that I have three Armenian doctors who don’t want me anywhere near their grape leaves. Uro said, “No! You have three Armenian doctors telling you to eat meat!”
I missed you Spiky !! Your humor is a damn riot.
So last week I had ultrasound of kidneys and bladder. My symptoms were like bladder spasms and dull ache in lower pelvis. Urinalysis showed no bacteria but mucho blood (not visible). So, I'm still waiting for official report and game plan but I'm told I have a left kidney full of stones. WTF? I'm afraid to take my calcium supplements till I know what the heck happens next !!! Actually I'm scared and quit all my vitamins in fear !! How do I find out the composition of my renal rocks???
 
I missed you Spiky !! Your humor is a damn riot.
So last week I had ultrasound of kidneys and bladder. My symptoms were like bladder spasms and dull ache in lower pelvis. Urinalysis showed no bacteria but mucho blood (not visible). So, I'm still waiting for official report and game plan but I'm told I have a left kidney full of stones. WTF? I'm afraid to take my calcium supplements till I know what the heck happens next !!! Actually I'm scared and quit all my vitamins in fear !! How do I find out the composition of my renal rocks???
(As she plays a doctor on the internet...) NO! That’s bass-ackwards (if we’re talking calcium oxalate stones, which are the most common)! Most calcium oxalate stone people are told to consume MORE calcium!

From this site:
https://www.kidney.org/atoz/content/calcium-oxalate-stone

When fat is not absorbed the right way, the fat binds to calcium and leaves oxalate behind. The oxalate is then absorbed and taken to the kidney, where it can form stones. Similarly, following gastric bypass surgery, your body absorbs less calcium from your digestive system. Because of this, higher levels of oxalate are found in the urinary tract. The build-up of oxalate can form crystals, which can form kidney stones.


If you miss people here, stop staying away, silly! And one of these days, I might be able to make it all the way to the county line and we can do Starbucks or something!
 
i had my DS in Jul2018, and have kidney stones. to the defense of the DS, i had kidney stones prior to having surgery.. for about 10 yrs. a couple mths ago in Oct, I had to have surgery to have a stone removed from my left kidney that was stuck in my distal ureter, and urologist also removed the other stones in my left kidney - it had been there for a while and was starting to grow into my ureter. i also have stones in my right kidney (like 3-4 small ones according to the ultrasound), but those were left in. after having my urine collected over a 24 hr period, i have tons of sodium being excreted in my urine, and tons of oxalate, and calcium too (if i rem right). so was just put on potassium citrate and told to lower my sodium to 3g/day, added vitamin b6, and drinking 100oz of lemon water.... AND to omit high and moderate oxalate foods. i also have to meet with a nephrologist and have a CT of my left kidney to see why i still have residual swelling. i also want to add too that i have added in foods that i know i shouldn't - chips, oatmeal, chocolate, wheat bread. but i'm not sure that these "no-no" foods are solely the cause. four months after my surgery, when i had my bloodwork done, i had a moderate amount of oxalate crystals in my urine, and within a week after this, i passed a stone - and i was eating nothing but protein and fat and plain water. i'm hoping i can get this situation under control because i don't want to continue to have issues with my kidneys
 
i had my DS in Jul2018, and have kidney stones. to the defense of the DS, i had kidney stones prior to having surgery.. for about 10 yrs. a couple mths ago in Oct, I had to have surgery to have a stone removed from my left kidney that was stuck in my distal ureter, and urologist also removed the other stones in my left kidney - it had been there for a while and was starting to grow into my ureter. i also have stones in my right kidney (like 3-4 small ones according to the ultrasound), but those were left in. after having my urine collected over a 24 hr period, i have tons of sodium being excreted in my urine, and tons of oxalate, and calcium too (if i rem right). so was just put on potassium citrate and told to lower my sodium to 3g/day, added vitamin b6, and drinking 100oz of lemon water.... AND to omit high and moderate oxalate foods. i also have to meet with a nephrologist and have a CT of my left kidney to see why i still have residual swelling. i also want to add too that i have added in foods that i know i shouldn't - chips, oatmeal, chocolate, wheat bread. but i'm not sure that these "no-no" foods are solely the cause. four months after my surgery, when i had my bloodwork done, i had a moderate amount of oxalate crystals in my urine, and within a week after this, i passed a stone - and i was eating nothing but protein and fat and plain water. i'm hoping i can get this situation under control because i don't want to continue to have issues with my kidneys

I am of the opinion…based on ZERO scientific training or education…that the DS can exacerbate a pre-existing kidney stone issue.

I didn’t have stones pre-DS. But now I do get stones...in my left kidney. If it were JUST the DS, the problem ought to be bilateral. Having a mess on one side suggests that, like you, I had issues pre-DS, but in my case, I was unaware.

My guess is that you will need to adjust to the idea that you will need to be constantly vigilant, take the supplements, avoid the oxalates, and…maybe…remind yourself that this is the price you are paying for not being morbidly obese and having a shortened life.
 
I'm another stone former that was this way long before my DS, but the link from Spiky above pretty much sums up what my nephrologist says, as well as my having low citrate. I take a prescription for raise the urinary citrate to make it harder for stones to form in the kidney. My kidney stone issues were likely hereditarty, and several generations have had them, and have even died from complications with them, but I was told my DS most certainly exacerbated them. We know more about them than previous generations, and the the increase in the calcium (ALWAYS taken with any food eaten) and the potassium RX have made a huge difference in reducing mine (and the low oxalate diet did absolutley nothing to help).
 
I'm another stone former that was this way long before my DS, but the link from Spiky above pretty much sums up what my nephrologist says, as well as my having low citrate. I take a prescription for raise the urinary citrate to make it harder for stones to form in the kidney. My kidney stone issues were likely hereditarty, and several generations have had them, and have even died from complications with them, but I was told my DS most certainly exacerbated them. We know more about them than previous generations, and the the increase in the calcium (ALWAYS taken with any food eaten) and the potassium RX have made a huge difference in reducing mine (and the low oxalate diet did absolutley nothing to help).

It didn’t even make you grumpy and start craving strange things...like a Shrimp Louie Salad?
 

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