What is Medullary Sponge Kidney?

If, for some strange reason, you set out to design a kidney that could form stones as quickly as possible, you might end up with something like a medullary sponge kidney.




Medullary sponge kidney (MSK) is a condition in which a portion of the kidney known as the medullary pyramid is found to have dilated tubules (tubules are small tubes through which urine drains) and numerous small cysts (cysts are fluid filled hollow spaces). The cysts are small, measuring from 1 to 8mm, but are numerous. The cysts give the kidney, when cut, the appearance of a sponge – from which the name of “medullary sponge kidney” was coined. These cysts and dilated ducts lead to poor drainage, making it easier for stones to form. These abnormalities can be seen throughout both kidneys or may be localized in only one part of a kidney. The stones formed in MSK tend to be numerous and scattered throughout the kidney.

How do I know if I have medullary sponge kidney?

Medullary sponge kidney is felt to be non-hereditary (you don’t pass it on to your children). Many patients with MSK never develop problems and don’t know they have the condition. One study estimated that MSK may occur as commonly as 1 in 200 persons while other more conservative estimates report an occurrence rate of 1 in 5,000 to 20,000 persons.

Because many patients with MSK develop no symptoms and remain undiagnosed, reliable data on how many will form stones is not available. In one study of 56 patients from one hospital, the authors reported that 30% of the MSK patients that they studied never developed stones. Among the stone formers, MSK appears to be more common in females and usually first presents in the 30s.

The diagnosis of medullary sponge kidney is made with imaging studies, either with an intravenous pyelogram (an older type of x-ray) or with a contrast CT scan. These imaging studies will show a characteristic distribution of stones or calcifications in the location of the medullary pyramids and contrast pooling in dilated tubules.  In order to confirm the diagnosis, the imaging study should include intravenous contrast in order to demonstrate the dilated tubules that are the hallmark of MSK. However, most CT scans for kidney stones are performed without contrast and in this case the diagnosis, while likely, is not considered definitive because other stone related conditions can also lead to an appearance similar to MSK on a non-contrast CT scan.

Non-contrast CT scan of a  patient with medullary sponge kidney. Multiple stones and calcifications can be seen in both kidneys. To see examples of contrast accumulating in the medullary pyramids of MSK patients on a contrast CT scan or intravenous pyelogram, visit these sites: CT scan or intravenous pyelogram.

What are the symptoms of medullary sponge kidney?

McPhail and colleagues reported that among 56 patients with MSK, the most common presenting symptoms included:

  • Flank pain in 52%
  • Microscopic blood in the urine in 36%
  • Visible blood in the urine in 16%
  • Urinary tract infection in 7%
  • Abdominal pain in 7%
  • Testicular pain in 4%
  • Imaging for other causes in 4%

What type of problems can medullary sponge kidney cause?

Individuals with MSK most commonly present with kidney stones, urinary tract infections, or blood in the urine. In individuals with MSK who form stones, other metabolic abnormalities that predispose someone to form stones are also commonly found, including hypercalciuria (high calcium levels in the urine) and renal tubular acidosis (a disorder with the kidney’s handling of acids).

It therefore appears that just having MSK by itself is not enough to form stones (30% of MSK patients don’t form stones). However, combine the abnormalities found in MSK with someone who has a metabolic tendency to form stones and you will often see an astounding number of stones developing throughout the kidneys.

X-rays for patients with MSK are often impressive for the sheer numbers of stones seen. Not all those stones will necessarily be in a position to drop into the ureter and cause traditional stone symptoms. In order to do so, the stones need to have access to the hollow collecting system portion of the kidney. Instead, many are often embedded in the solid tissue of the kidney (the parenchyma) where they are unlikely to result in a stone passage.

In some patients however, the non-obstructing stones seen in MSK can be associated with significant and chronic pain, even if they are not passing. The pain in this situation can be constant in nature, unlike the episodic pain traditionally seen with kidney stones. It is not certain what causes this pain but authors have proposed that the small numerous stones seen in MSK may cause obstruction of the small tubules and collecting ducts in the kidney, leading to the pain. This pain can be debilitating and treatment is challenging. Narcotic medication, even with large quantities, is often not adequate. Some success with pain control for MSK patients with this type of pain has been reported using laser lithotripsy (see below).

The most common stone types in MSK are calcium oxalate and calcium phosphate.

Thankfully, MSK does not commonly lead to kidney failure.

What can be done about medullary sponge kidney?

Treatment for MSK focuses on prevention and treatment of stones, management of pain, and prevention of infections. There is no treatment available to fix or remove the small cysts and dilated tubules associated with the condition.

In stone formers, maintaining a high fluid intake and treatment with hydrochlorothiazide (to lower urinary calcium) and/or potassium citrate (to raise urinary citrate) are used. Metabolic evaluation with urinary and blood testing can be used to identify specific metabolic abnormalities that increase a person’s risk for stones. In addition, some authors advocate the use of hydrochlorothiazide in all patients with MSK, even when urinary calcium levels are normal.

Treatment for stones that have already formed include the same approaches used for other stone patients, including ureteroscopy, shockwave lithotripsy, or less frequently, percutaneous nephrolithotripsy. Due to the large number of stones formed in MSK and the fact that many of those stones may not be within the collecting system, it is not usually necessary or possible to completely eradicate stones in a patient with MSK.

In patients who have chronic pain associated with MSK, ureteroscopy with laser lithotripsy (called “ureteroscopic laser papillotomy”) may be an option to relieve discomfort. The procedure involves fragmenting and extracting all visible stones in the kidney with the intent to “unplug” and clear obstructed ducts that may have stones trapped in them. In a paper from three institutions, Gdor and colleagues reported on their experience with a total of 65 patients who collectively underwent 176 procedures. All  patients in the study had chronic flank pain and multiple non-obstructing kidney stones. 50 patients had followup information available. The majority of patients who underwent this procedure experienced a reduction in their pain (83%). On average, the duration of pain relief from surgery was 26 months.  Of note, 17 of the patients in the study had a diagnosis of MSK and their pain relief was similar to that seen in non-MSK patients.

If you have been diagnosed with medullary sponge kidney, share your experience or ask a question below.


Campbell-Walsh Urology 10th Edition, 2011.

McPhail and co-authors, “Nephrolithiasis in Medullary Sponge Kidney: Evaluation of Clinical and Metabolic Features”, Urology 2012.

“Medullary sponge kidney” National Kidney and Urologic Diseases Information Clearinghouse, 2008.

Gdor and co-authors, “Multi-Institutional Assessment of Ureteroscopic Laser Papillotomy for Chronic Flank Pain Associated with Papillary Calcifications”, Journal Of Urology 2011.

Editor’s note: This post was updated on 5/15/12  to include more information on diagnosis, pain related to medullary sponge kidney, and treatment options.

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109 Responses to What is Medullary Sponge Kidney?

  1. Jenny says:

    I am so sorry I had this from 1994 when I was in my 30s i am 54 so I understand.

  2. xochilt says:

    I was diagnosed with msk when I was 16, at that time I drank carbonated drinks and coffee like nobobdys business and wound up with severe pain, in my kidneys and in my bladder, I had to pee constantly and that would hurt and cause irritation to my bladder which would then lead me to have blood in my urine. I stopped drinking soda and coffee and that helped sooo much. However im 25 and its starting up again, I don’t know what else I should avoid eating/drinking and suggestions????? I cant live like this and its so frustrating because I feel like my boss does not understand how severe the pain is, and its hard for others to understand because their not going through it. Its almost like people think im exaggerating the pain. I don’t want to feel like this, it just is. They need to get more information on this condition, because before I was diagnosed I saw at least 7 other doctors who hadn’t a clue why I was in such pain and left me and my mother with dead ends.

    • Wayne Albrecht says:


      You are going to have to find a good urologists who understands the pain associated with MSK. I have the same pain if I have stones or do not have stones; it is frustrating.

      Since I have been on Potassium Citrate for the last couple years, the stone formation has been reduced significantly…but…I still have pain from the MSK itself. Plenty of water, lemon juice…reduce salt intakes… increase excercise. I feel I have uilt up an intolerance somewhat to the low level pain and can ignore it…sometimes I can’t. Hot baths help me at times.

      It’s hard to say what will work for you until you and a good urologist sit down and work on it.

      I’m sorry for your pain and I understand your frustration fully.

  3. Tina in hell says:

    I have this disease it is so bad i cant stand the pain at times last hospital visit Nov. 2013 had me in there for a week under heavy drugs yay me NOT i cant work i can barely get out of bed some days and it started after the loss of my fiancee in 2011 i almost died in 2012 due to sespis and in ICU for a week and this now is my life of hell pain and hospital stays

  4. WizRose says:

    7 yrs ago my kidney hell began with a 4cm stone, yes I said cm not mm. All my life I’ve had UTI’s once a month, but never presented with the normal symptoms. Meaning pain was always in my back, not front or burning when urinating.
    That first stone equated to 8 surgeries in 6 wks. Stones that big are “once in a lifetime” stones, except I made one every 6 mo after that. Even the docs were mystified. Back pain has been my world since 1990 when I hurt it, so always chalked pain up to that. Ultimately the violent vomiting that goes with blockage forced me to have my back fused & facing a cervical fusion too.
    3 yrs ago MSK popped I nto the picture with a Ct scan. I felt like a walking medical freak. By this point docs had determined I have Rheumatoid arthritis, sogren, fibromyalgia, and now this. I felt like they didn’t have a clue and I was suffering vecuSe of it. I am a well educated person with extensive medical background and the pieces didn’t add up. Ironically it was while attending clinic with my FIL who had ALS that numerous pieces clicked. His treatment included ALL his docs, RX, social workers, and they gave a binder of information for us to read. Having everyone in 1 room discussing his treatment meant zero ping ponging and accurate info. Being the techie I am I facilitated a virtual appointment with my docs (family, RA, Ortho, urologist, nephrologist) and it was a come to Jesus meeting. The whole if stones aren’t in ureters debate began and I reviewed my case history with them. If pain is caused by inflammation and spine isn’t the cause, but each kidney has 30+ stones in it, wouldn’t it stand to reason that they are causing irritation hence the pain? Dead silence for more than a minute. I asked them to set aside all the rhetoric and look at his from an anatomy/ physiology standpoint. Ultimately additional tests were done and it showed kidneys inflamed, without infection, no stones in urethers, pain present, with or without blood and they came to the conclusion that the inflammation ground the stones together, we all know a stone is like having an internal “sticker” you pick up in fields, and the stones stuck in the ducts was the equivalent of being lacerated from the inside. Really? Ya think? What is still unknown is the inflammation trigger- RA, just the presence of the stones, possible duct blockage, illness….
    In the end, I type this while dealing with a particularly nasty bout of pain without actual moving stones, but I did accomplish 1 thing- I’m not crazy and docs can’t continue their rhetoric when faced with the collective knowledge of many docs in the room.
    I’m okay with the medical community saying “I don’t know” or “there is no treatment”, but I’m nOT okay with being passed off as nuts. Don’t insult my intelligence and no I don’t want narcotics. I deal with pain everyday- it’s a constant companion and some days are better than others, but currently pain management only offers meds which makes everything worse. I LivE everyday, I don’t just want to exist each day. Like everyone with this disease some days are tougher than others, each day I take meds, but save the big guns as much as possible, I also choose to make the best of each day and rarely talk about being in pain. It’s my burden, not others. So I have a variety of coping strategies or pain avoiders I utilize and “do” my day the best I can.

    • Wayne Albrecht says:


      I really appreciate your story and your efforts to get to the bottom of your pain. I agree with you very much on “save the big guns as much as possible” comment. Taking too much of the pain meds only makes things worse on the body and mind; better to avoid them until you absolutely need them.

      I aso appreciate your comment of “it’s my burden, not others” and utilizing pain strategies to avoid pain. That has been my life for the last 11 years!

    • Jenny says:

      Wayne I no how u feel my with kidney stone or msk was in 1994 and I have been in pain and uti I do not know how to live by life with out a pill.

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  6. Wayne Albrecht says:

    I was diagnosed with MSK in 2002 when I was 41 (I am now 52). Have had more Litho’s than I care to mention and one surgery to remove the stone from the right kidney because the stone was to large (about an inch in diameter) to pass.

    I have pain most all the time with and without stones present. I struggle asking for the pain meds and just deal with the pain. I have a high tolerance for pain in my kidneys. I would rather not take the meds; but I have. My wife “makes” me ask for them from the urologist in case the pain gets too hard to manage. My wife will routinely ask me what “level” I am at on any given day….normally I am at a 3-4 on the Happy Face scale.

    I have been taking potassium citrate for about a couple years now and, to my surprise, has significantly slowed down the formation of new stones. But, as I said, the pain I experience comes with or without the stones present.

    I have passed hundreds of stones over the last decade and all of them – exception being the one surgically removed – have passed without any complications. I drink well more than 64 ounces of water a day and that seems to help keep me flushed out pretty good.

  7. jeremy k ambrose says:

    I have this condition for a long time i guess. I think i was born with it.after reading the following material.it informed me alot about why my left flank hurts so much and traces of blood is always present in my urine when i go to the urologist. I was hit by a car when i was 13 and started getting kidney stones at 18 i think like every 2years but my back would hurt under my shoulder blade when they started working down i had a problem passing the stones at first for 4-6 years but it eases up after it only hurts when it leaves the kidney now i can deal with the pain but after doing a little hard labor my back really hurts then pain meds wont stop the pain it will just make u more sensitive to the pain if prolong use i found that jogging / running helps a bit a healthy diet veggies fruit and meat try not to eat to much dairy or sodium. I cook all my food so i know whats in it nothing from a package. Starches i try to stay away from.not very often do i find a need for med use very rarely.

  8. Tammy says:

    Currently, I am in the process of researching MSK. I am set for an appointment at SWUT Mineral and Metabolism Center in Dallas in October. As I prepare for my appointment, I have collected my medical records. I found a note in January, 2010 that states suspects MSK as a finding in a CT scan… My Urologist is confounded by my chronic kidney pain and during lengthy hospital stays, I’m subjected to a ton of other tests because “it’s just not possible for non-obstructing stones to cause pain”.

    I have “too numerous to count” stones in both kidneys. Only the large stones (4mm – 10mm) are being measured.

    ESWL is no longer an option for me. They are not able to “see” the stones clearly enough to target them. My Urology team says the stones are not in a position to perform Percutaneous Nephrolithotomy, so I’m left with – “just deal with it”, “expect frequent and lengthy hospital stays”… Oh! And the new one is, “We don’t prescribe pain medicine, you have to go to pain management for that.” But, four months later and still waiting for a valid referral.

    I am hoping the Mineral and Metabolism Center has something for me. Sometimes I think that just naming the monster inside me will help resolve some of the anxiety that I have and to validate that I am not crazy or a drug-seeker.

    I have never passed a stone, so we don’t know what type of stones I have. The 24-hour urine collection wasn’t indicative of a particular stone type either… A new collection will be done next month along with my visit to Dallas….

    Does anyone know about insurance coverage and MSK in the US??? My doc says I’ll be dropped if I get a diagnosis.

  9. Christina says:

    I am 25 and have had ongoing problems with UTI’s and stones since 21. It was only until last week I was diagnosed with MSK among my other health issues. I was told a year ago that I had “spongey kidneys” but no one elaborated on that. Last week I was in emergency three times in five days and treated like a junkie looking for drugs. My family doctor then explained to me that I have MSK and though we can do things to try and manage it, there is no gaurentee of results. I have already started changing my diet and upping my fluid intake but have been in a very large amount of pain. I am now on a pain management plan so I can work and take care of my kids, and on a wait list for a specialist. Any tips on healthier ways of pain management for this?

  10. Christine Ormsby says:

    I was diagnosed at age 34 with MSK after passing a kidney stone. I also passed sugar in my urine from time to time but was not diabetic according to the glucose tolerance tests. At age 51 I was diagnosed with osteoporosis and osteopenia and put on bone medicines. I tried all the different ones over the years with very poor increases in bone density. At age 65 the bone density is a little worse. I have taken a variety of calcium supplements since age 40. I recently did some research and it looks like there is a correlation between MSK and osteoporosis. If this is true, perhaps the MSK is the underlying cause of the bone loss. After a visit to the doctor we discussed the entire history. I have had no known flareups with the MSK, have a great healthy diet and am in good general health. I may be passing some small crystals in the urine from time to time. The doctor is going to forego the bone medicines in favor of: Metagenics Cal Apatit Forte Capsules (MCHC with Vit D) for bone building, and Ostera from Metagenics for Bone Remodeling as well as Potassium Citrate with blood tests again in two weeks after the new dosing.

    Do you have any information on MSK and osterporosis for both myself and my doctor that will help us to better understand what might be going on.
    Thank you,

  11. Nichol Ward says:

    More research needs to be done! It took 10 yrs for me to be diagnosed & I’m only 30! I’m treated like a hypochondriac & a drug seeker when I see a doc b/c there are no ‘passing’ stones on my CT. I’ve got 12 right now & just had lithotripsy in Nov 2012. I’ve reached out to the kidney foundation & various doctors but of course that makes it look like I’m doctor hoping for pills (not an answer-that I desperately need). I hate taking pain meds but unfortunately, it’s the only way I can function on some days! This is such BS! BTW my half sister also has MSK-pretty funny seeing as how it’s not hereditary!

    • M says:

      My experience exactly. And even after lithotripsy when I’m passing the fragments of the original 2 cm stones, I’m still treated like a drug seeker. And the pain is constant!

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  13. Carla Kudrna says:

    I got my 1st kidney infection when I was 18 and was hospitalized, and my 1st stone when I was 20 and pregdent. I am know 33 and have been diagnosed with MSK. I have had many litho treatments done but got to the point of not wanting them because in less then a month my left kidney would be full of stones again. I have had a bunch of urologist that all told me something different:( they have put me though a bunch of surgeries :( In Dec 2012 I was told I have MSK. But at the same time she also told me this would not be why I’m in pain. She told me only if I was passing a stone would it cause pain, and that if I was passing a stone to go see my family Dr. She told me that in the Summer it would get worse:(
    Well I went in to my family Dr. in so much pain she put me on pain meds. I showed her this page, and seem to help her understand. But, she has now sent me to pain management. So, now I’m starting over with another Dr. :( he is trying to help me find something that will help.

    My question to all is do you work? I really want to go back to work (now that the kids are all in school) but I’m always in pain and on meds. My family Dr has told me to file for Social Security disability. Has anyone done this?

    I hope all with MSK can find something that can help them

    • bonnie neville says:

      Carla, yes…I filed for disability and recieved it. I was told by the case-worker at social security that only those whom are missing a limb, on dialysis, or blind receive it right away. She looked at my records and said “you definitely need to be on disability as your doctor advised and you can count on getting it, but you have to stick with the process and don’t miss a date”. If you drop out of the process (filling forms, getting records, filing appeals by designated dates – then you don’t need disability is the assumption at Social Security, and it makes sense as many abuse the system). When you file, have all of your medical records from EVERYWHERE that you have records, have your doctor write a referral for you (it HELPS). I would use a lawyer to expedite the process a bit, or just to make sure NOTHING is missed and no step is skipped or forgotten. Most do not charge but will take a percentage if you have retroactive monetary award. Good luck to you. When your doctor suggests this…it is TIME to do it. I held out for years because I loved my job , I loved working and I worked very hard physically, but ultimately it was the love of hard physical work that maded it harder on me. ;)

    • JW says:

      File for social security disability – it takes awhile so go ahead and start the process. I did, after finally giving up trying to work a FT career, tried to go to PT then gave up….but I also have neck/shoulder issues, had ruptured disc in my neck in Dec 2012 and had the fusion surgery – and I suffer from this MSK constant flank pain. I had the itty bitty one little stone taken out by my awesome urologist in March of 2012….and been doing great. Well that same right kidney is hurting bad past few weeks, then I got really sick Saturday – diahrea all day and violent vomiting, but no fever. Went to urologist yesterday, and guess, what…of course my right kidney is “enlarged/swollen” so in a few hours I’m having surgery – he is not 100% sure why it’s swollen so he’s doing a uteroscopy thing to go in and see what’s going on. I am already on disability. Keep all names and address of ALL doctors you see, regardless of why. Take good notes, and be 3 steps ahead of social security and the attorneys….have your records and tests ready b/c it takes much longer for your attorney to do the record requests…they will do this anyway. Go ahead and apply online first yourself, get the usual first denial, then appeal….you may get another denial of that appeal, then that’s when I got in touch with the SSD attorneys – they will take on your case from there…they take a percentage of what your backpay ends up being. Your backpay will be back to the very first date you applied (so do it today!!!) It’s not to hard at all to do it online. Get the process rolling…Trust me it’s hard to accept, I’ve been working since I was 14 yrs old….I started having chronic pain in my shoulders and neck around 2005 and it got worse from there..tendonitis to bursitis, to arthritis, neck is full of arthritis – both shoulders have lost range of motion, and my neck. I’ve done it all, physical therapy, injections, chiropratic, still in pain management clinic…which is helping for my neck tremendously – HOWEVER, YOUR BODY BECOMES SO DEPENDENT AND TOLERANT OF PAIN MEDS they quit working well – but when it comes to this darn kidney, forget it…i have not found a single med to help with that but a heating pad. If I get the hard stuff in my IV,…boom neck and shoulders feel awesome, but it passes that kidney as if it wasn’t even there!!! Amazing stuff that kidney pain….but of course, I’m just another drug seeker hypochondriac (spell??) It gets rough I know….I have a degree and had a great HR career….got fired for absenses….not to mention I have two kids so when they were small and got sick (one has asthma) then heck, what do you do from there ( and I was the HR manager go figure, I created the attendance policy etc.). Sorry on a rampage…in pain. Go file for SSD now. It’s all about the medical records…if you have them, you are better off and the more you have the better. If you don’t have records, it’s harder to prove you are serious and deserving of getting your “own money” that you have paid into since you have been working.

  14. Guy Stone says:

    If you’re in the Toronto area, ask for a referral to the Stone Clinic at St. Michaels. I don’t know about other cities and provinces. Your doc shouldn’t be unconcerned, in spite of not knowing how to deal with it. No blame there – it falls under nephrology, not family medicine. If you have access to a teaching hospital, that would be the place to start, and where you’d probably end up.

    Don’t expect anything to prevent you from making stones. There are lifetime medications and dietary restrictions that are recommended along with the usual “Drink Lots Go Often” mantra. The thing is, the treatments are valid statistically to reduce the frequency in a group, but for any individual, there’s no way to prove any effect. The fact that stones run in your family indicates there is probably a relevant prescription.

    I’m a 70 year-old male with MSK + family history. Most of my stones pass, which is a good thing and a bad thing as we all know. 35 years ago when I started it was major surgery to remove it if one got troublesome. Nowadays often it can be done without a scalpel. Medical and dietary recommendations have also changed over that time.

    All there for some complaints is up-to-date best practices, not necessarily cures.

  15. Sarah Bolton says:

    I was diagnosed in 1995 with MSK and I have had many stones removed my first urologist was always concerned and now my pc family doctor isnt concerned as much. I deal with a lot of pain on both sides and has recently changed doctors again. I think its something more to whats going on now. I need more insight.

  16. Kathy says:

    I was diagosed after my 4th pregnancy, I was in my late 30′s. I am now in my late 40′s. I haven’t had any real issues until now. Kidey stones are rampant in my father’s family but no one else has MSK. After reading others’ comments on this site, it is all making sense to me: flank pain, sharp, burning, constant pain in my left side with higher intensity in the morning upon waking. Similar pain to labour. Nothing seems to help. Awaiting results from recent ultrasound but now I am worried. The urologist who diagnosed me is no longer practicing here and my family doc seems unconcerned. I had been told that I would never be able to pass stones given the anatomy of my kidney. I have lots of stones on both sides but obviously now something is not right- maybe a blockage? infection? Is surgery the usual option if there is a blockage? or? Is there any doc who is considered a specialist or expert that anyone knows about? Looking for help in Canada.

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