Hi Dan—great post, you’ve clearly put a lot of thought and research into this. I read the whole thing.
I’m a (predominantly) emergency doctor so the title of your post caught my eye. I can certainly confirm that stone-related pain brings even the most stoic amongst us through the doors of the ED to seek out help!
There were a couple of points that came to mind reading your post (and please feel free to take or leave them as you will, they are just preliminary thoughts and I’ve not put my own research into it, these are just my thoughts and my thoughts with my anecdotal doctor’s hat on):
Pain vs Suffering: As you’ve alluded to, pain can be quite unwieldy in its characterization and description. It’s also hugely tied to emotions, expectations, and outcomes. Whilst kidney stones are objectively and subjectively incredibly painful, I’ve often found that a good explanation of the cause of the pain and the assurance that it WILL pass with time is very reassuring and so the overall suffering attached to that pain experience is less say than the emotional suffering I’ve seen in patients with chronic intractable pain or pain that has no physical attributable cause (sometimes called functional pain). I do agree though that suffering attached to stones that don’t just pass and the operations etc. that might need to come after that can be unpleasant (interestingly and again anecdotally stent-related pain seems to be as bad if not worse than the stone itself and those things can stay in for months!). I just wonder whether it’s overall a big enough burden of suffering amongst the other forms of pain/suffering to warrant rigorous efforts to alleviate/prevent it.
Regarding small stones being downplayed: I don’t know that they’re necessarily downplayed (even if found as an ‘incidentaloma’ - for those not familiar: something that pops up on a scan that you weren’t looking for; from incidental), but for small stones not causing pain or obstruction, we don’t do anything about them straight away, yes (because they might pass and because ‘doing’ things in medicine is always a trade-off of doing harm vs benefit ie doing stent surgery (in the absence of something to make it go away otherwise) without good cause confers a lot more suffering than an asymptomatic stone!).
Radiation stigma: Again, this is a combination of reason and intuition but on the balance of all things considered (ie knowing the disease process, its likelihood etc), would I have a CT scan for a screening test at present? No. Regardless of how low the radiation is, as a young woman, it’s a cumulative risk I’ll avoid if I can. I think this way for patients too. I guess there’s different thinking with age and benefit; mammograms as a screening modality for breast cancer would be an example. Also obviously, US or MRI would remove the radiation risk but then you run into cost and access issues (also a consideration for CT scans) and the need for skilled sonographers.
I guess I say the above with the idea that in this space, the preventative approach seems more promising to me in terms of its cost-effectiveness and scalability than the diagnostic or therapeutic approaches. I’m also generally excited about the advances in medical imaging and the intersection with AI that are coming about!
Anyway, thanks again for your post, it was interesting for me to read.
I’m just seeing your comment now for some reason. This is super helpful.
Regarding your first point (pain vs suffering), that’s pretty interesting and makes sense. I would just note that the degree to which people can detach from painful experiences varies. Regarding suffering from operations and stents, I have heard the same thing about stents, and that is something we would have to factor in, I think, to a Fermi estimate of the amount of suffering that could be alleviated with early interventions for kidney stones. I wonder if someone could invent a stent that actually diffuses a bit of anesthetic around it while it is in (my understanding is the stents are typically only temporary in place).
Regarding the second point “Regarding small stones being downplayed:”. So, after writing this I looked into it a bit further because I was interested in whether an AI application assisting in early detection might be high value. The idea that radiologists miss tiny stones is only my personal guess. I have only seen 1-2 examples of this, when I was running a system I developed for stone detection and it found stones in CT colonography scans that were not mentioned in the report.. but those 1-2 examples only surfaced after running on over 6,000 scans.
Regarding how what happens with tiny stones: data on this subject is very scarce, but it seems most tiny stones resolve on their own without major symptoms (?). It’s really not very clear. I found one paper which covers this question, although it doesn’t directly study it. Looking at CT scans for CT colonography they found that 7.8% of patients (all middle aged adults) had asymptomatic stones. They then found that only 10% of patients with asymptomatic stones were later recorded as having symptoms over a variable follow-up interval that extended to a maximum of 10 years. So it seems the tiny stones don’t cause symptoms… but maybe it takes longer than 10 years before they start to manifest symptoms.. Probably having a tiny stone puts you at massively higher risk for a symptomatic stone event later in life. There’s very little data on this question or about stone growth dynamics across lifespan in general.. it’s not something that’s very easy to study. Basically, scanning people with CT just to monitor their stone size is absurd, so to study this we have to mine historical scans and then try to find follow-up scans to see if the same stones are still there, and compare their volume (which is a bit tricky to do accurately when the scan parameters change). This is an application for deep learning based automated stone segmentation algorithms, actually, to assist in doing such a study. We have a conference paper under review that actually does this although I have to say it’s technically and logistically challenging to do.
Regarding the third point, “Radiation stigma”: I agree, I think the way you are thinking about this is pretty in line with the risk-benefit calculus as far as I understand it. I should have elaborated a bit more, in my post. I was not thinking of doing a screening CT only to screen for kidney stones. I’ve been working with Prof. Pickhardt at UW. One of the things we’ve been researching is the utility of a low-dose “screening CT” in middle age. The screening CT would cover many things including stones. Prof. Pickhardt is working on assembling data to support this idea, mainly focusing on the value of scanning just the abdomen (not the chest). People currently get a coronary calcium score (“CAC”) CT scan for screening their cardiovascular risk. The abdomen also contains biomarkers (like aortic plaque) that also can gauge cardiovascular risk, plus we can look for a lot of other stuff in the abdomen, including kidney stones.
I agree the preventative approach is probably the most promising (identifying patients at-risk using genetics, blood tests, and maybe other factors, not screening CT) .. especially given how safe and cheap potassium citrate is.
Hi Dan—great post, you’ve clearly put a lot of thought and research into this. I read the whole thing.
I’m a (predominantly) emergency doctor so the title of your post caught my eye. I can certainly confirm that stone-related pain brings even the most stoic amongst us through the doors of the ED to seek out help!
There were a couple of points that came to mind reading your post (and please feel free to take or leave them as you will, they are just preliminary thoughts and I’ve not put my own research into it, these are just my thoughts and my thoughts with my anecdotal doctor’s hat on):
Pain vs Suffering: As you’ve alluded to, pain can be quite unwieldy in its characterization and description. It’s also hugely tied to emotions, expectations, and outcomes. Whilst kidney stones are objectively and subjectively incredibly painful, I’ve often found that a good explanation of the cause of the pain and the assurance that it WILL pass with time is very reassuring and so the overall suffering attached to that pain experience is less say than the emotional suffering I’ve seen in patients with chronic intractable pain or pain that has no physical attributable cause (sometimes called functional pain). I do agree though that suffering attached to stones that don’t just pass and the operations etc. that might need to come after that can be unpleasant (interestingly and again anecdotally stent-related pain seems to be as bad if not worse than the stone itself and those things can stay in for months!). I just wonder whether it’s overall a big enough burden of suffering amongst the other forms of pain/suffering to warrant rigorous efforts to alleviate/prevent it.
Regarding small stones being downplayed: I don’t know that they’re necessarily downplayed (even if found as an ‘incidentaloma’ - for those not familiar: something that pops up on a scan that you weren’t looking for; from incidental), but for small stones not causing pain or obstruction, we don’t do anything about them straight away, yes (because they might pass and because ‘doing’ things in medicine is always a trade-off of doing harm vs benefit ie doing stent surgery (in the absence of something to make it go away otherwise) without good cause confers a lot more suffering than an asymptomatic stone!).
Radiation stigma: Again, this is a combination of reason and intuition but on the balance of all things considered (ie knowing the disease process, its likelihood etc), would I have a CT scan for a screening test at present? No. Regardless of how low the radiation is, as a young woman, it’s a cumulative risk I’ll avoid if I can. I think this way for patients too. I guess there’s different thinking with age and benefit; mammograms as a screening modality for breast cancer would be an example. Also obviously, US or MRI would remove the radiation risk but then you run into cost and access issues (also a consideration for CT scans) and the need for skilled sonographers.
I guess I say the above with the idea that in this space, the preventative approach seems more promising to me in terms of its cost-effectiveness and scalability than the diagnostic or therapeutic approaches. I’m also generally excited about the advances in medical imaging and the intersection with AI that are coming about!
Anyway, thanks again for your post, it was interesting for me to read.
Hi,
I’m just seeing your comment now for some reason. This is super helpful.
Regarding your first point (pain vs suffering), that’s pretty interesting and makes sense. I would just note that the degree to which people can detach from painful experiences varies. Regarding suffering from operations and stents, I have heard the same thing about stents, and that is something we would have to factor in, I think, to a Fermi estimate of the amount of suffering that could be alleviated with early interventions for kidney stones. I wonder if someone could invent a stent that actually diffuses a bit of anesthetic around it while it is in (my understanding is the stents are typically only temporary in place).
Regarding the second point “Regarding small stones being downplayed:”. So, after writing this I looked into it a bit further because I was interested in whether an AI application assisting in early detection might be high value. The idea that radiologists miss tiny stones is only my personal guess. I have only seen 1-2 examples of this, when I was running a system I developed for stone detection and it found stones in CT colonography scans that were not mentioned in the report.. but those 1-2 examples only surfaced after running on over 6,000 scans.
Regarding how what happens with tiny stones: data on this subject is very scarce, but it seems most tiny stones resolve on their own without major symptoms (?). It’s really not very clear. I found one paper which covers this question, although it doesn’t directly study it. Looking at CT scans for CT colonography they found that 7.8% of patients (all middle aged adults) had asymptomatic stones. They then found that only 10% of patients with asymptomatic stones were later recorded as having symptoms over a variable follow-up interval that extended to a maximum of 10 years. So it seems the tiny stones don’t cause symptoms… but maybe it takes longer than 10 years before they start to manifest symptoms.. Probably having a tiny stone puts you at massively higher risk for a symptomatic stone event later in life. There’s very little data on this question or about stone growth dynamics across lifespan in general.. it’s not something that’s very easy to study. Basically, scanning people with CT just to monitor their stone size is absurd, so to study this we have to mine historical scans and then try to find follow-up scans to see if the same stones are still there, and compare their volume (which is a bit tricky to do accurately when the scan parameters change). This is an application for deep learning based automated stone segmentation algorithms, actually, to assist in doing such a study. We have a conference paper under review that actually does this although I have to say it’s technically and logistically challenging to do.
Regarding the third point, “Radiation stigma”: I agree, I think the way you are thinking about this is pretty in line with the risk-benefit calculus as far as I understand it. I should have elaborated a bit more, in my post. I was not thinking of doing a screening CT only to screen for kidney stones. I’ve been working with Prof. Pickhardt at UW. One of the things we’ve been researching is the utility of a low-dose “screening CT” in middle age. The screening CT would cover many things including stones. Prof. Pickhardt is working on assembling data to support this idea, mainly focusing on the value of scanning just the abdomen (not the chest). People currently get a coronary calcium score (“CAC”) CT scan for screening their cardiovascular risk. The abdomen also contains biomarkers (like aortic plaque) that also can gauge cardiovascular risk, plus we can look for a lot of other stuff in the abdomen, including kidney stones.
I agree the preventative approach is probably the most promising (identifying patients at-risk using genetics, blood tests, and maybe other factors, not screening CT) .. especially given how safe and cheap potassium citrate is.