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Kidney Stone Size Chart In MM: Comparison & Treatment
Kidney stones are feared for the pain they cause, but they can be so small that the person passing them cannot feel them. On the other hand, they can be large enough to block the urinary tract, a common cause of complications. The largest kidney stone ever recorded was more than 5″ across at its widest.
The relationship between the size of a kidney stone and the pain they cause might be obvious, but the treatment also depends on the size. If a kidney stone is small enough to pass through the urinary tract at home and the pain it causes can be managed, a doctor might not intervene at all. You can get rid of these kidney stones at home. However, if a kidney stone is large, sharp, and potentially damaging, a medical or surgical approach is often warranted. These approaches include shockwave lithotripsy, kidney stone retrieval, stent placement, and even surgery.
Kidney Stone Size Chart
Below is a simple kidney stone size chart indicating the pain level and kidney stone treatment warranted for kidney stones of different sizes.
Size | Pain level | Treatment |
<2 mm | none | none |
2-4 mm | usually none | increased water intake |
4-7 mm | mild on urination | increase water intake and over-the-counter painkillers |
7-10 mm | mild on urination | ureteroscopy |
10-30 mm | extreme | shockwave lithotripsy |
>30 mm | extreme | percutaneous nephrolithotomy |
What Are Kidney Stones?
Kidney stones, or renal calculi, are hard mineral deposits in the kidney that become dislodged and travel down the ureter to the bladder and then the urethra to be excreted with urination. Depending on the cause, they can be made[1] of calcium, struvite, uric acid, or cystine, and they can range in size from tiny to as large as golf balls in extreme cases. As size increases, so does the level of pain the patient experiences and the complexity of the treatment.
Knowing the composition of the kidney stones that are produced can be important to knowing how to prevent them. Beyond staying well hydrated, since dehydration is the principal cause of kidney stones, your doctor might advise you to avoid certain foods to prevent the creation of new kidney stones. While such changes might seem inconvenient, they are far preferable to having another kidney stone, particularly if previous attacks have been very painful.
Kidney Stone Size Chart
As the kidney stone size chart above demonstrates, kidney stones smaller than 7 mm[2] can usually be passed at home, albeit with some pain involved. With small kidney stones like these, the most important guideline is that you increase your water intake to encourage the stone to pass. There is some evidence that apple cider vinegar is effective at smoothing the sharp edges of kidney stones and , thus, help them pass. Given the taste of vinegar, you might want to try apple cider vinegar gummies. Multiple brands are available, including Goli gummies.
For large-sized kidney stones, i.e., those larger than 7 mm, a doctor can perform ureteroscopy, in which a camera is inserted into the ureter, to determine whether the stone can be retrieved during the same procedure. If not, a stent can be inserted to ease the passing of the stone. For large kidney stones, the pain can usually be managed with nonsteroidal anti-inflammatory drugs (NSAIDs), whether over the counter (ibuprofen, naproxen) or prescription (e.g., ketorolac).
Size Chart For Stone Passing
For kidney stones larger than 10 mm or 1 cm, a more aggressive approach is required because the pain can be quite severe, and the stone can block the ureter, increasing the risk of infection, kidney damage, and even cause kidney failure. Often the pain is so severe that opioid pain relievers are required. Depending on the stone’s location relative to the bones of the pelvis, the doctor might perform shockwave lithotripsy[3], which involves using shock waves to break up larger kidney stones into smaller ones that are easier to pass. If the stone is too large to break up this way or the bones are preventing shock waves from reaching the stone, the patient might undergo percutaneous nephrolithotomy[4]. This is a minimally invasive surgical procedure in which a small incision is made in the back, through which the stone can be removed.
What Kidney Stone Size Is Harmful?
While any kidney stone is potentially harmful because their sharp edges can cut the body’s delicate tissues, smaller ones are usually not dangerous and can be passed with minimal management at home, including increased fluid intake and pain relievers. As a stone’s size increases, however, the likelihood that it will block the ureter increases as well, as does the chance that complications will occur.
The most common complication with kidney stones is a urinary tract infection (UTI) behind the stone, as urine blocked by the stone remains in the body too long. The urine can also build up in the kidney, causing a condition called hydronephrosis, which causes the kidney tissue to swell. Both untreated infections and hydronephrosis can cause damage to the kidneys that can be permanent if not treated in time. Kidney damage caused by repeated kidney stones can result in permanent kidney damage and chronic kidney disease, which might ultimately require hemodialysis or transplantation Therefore it is extremely important to note that water and certain foods have been purported to help repair the kidneys.
Finally, the most serious consequence of an unremoved kidney stone that has resulted in a UTI can be sepsis. This condition occurs when an untreated infection sets off a sort of chain reaction throughout the body, causing multiple organs to fail and potentially resulting in death. Although in the developed world, sepsis is a rare consequence of a UTI, any infection can potentially cause it and should always be treated.
When To See A Doctor
Since pain or blood in the urine is often the first symptom of a kidney stone, many people will visit the doctor right away, particularly if the symptoms persist. Since it is impossible to know the size of a kidney stone without an ultrasound examination[5], it is strongly advised that you see a doctor if a kidney stone is suspected so you can treat it properly. If the pain is severe or the volume of urine passed drops significantly, there is real cause for concern and medical care should be sought immediately. The doctor will be able to determine the size of the kidney stone and the best way to treat it.
Conclusion
The size of kidney stones varies and the symptoms associated with them will depend heavily on that size. From tiny kidney stones that cannot be felt and are passed without incident to large, sharp kidney stones that damage or block the urinary tract, each kidney stone requires a specific protocol to follow to pass it or undergo its removal successfully. The kidney stone size chart above can provide some guidance.
Frequently Asked Questions
Kidney stones are mineral deposits that develop in the kidneys and can dislodge and travel to the ureter, causing a variety of symptoms, from mild discomfort upon urination to extreme pain, infections, and kidney damage.
Kidney stones come in a range of sizes, from so small you can’t feel them to so large that they block the urinary tract and cause severe pain and serious complications.
Kidney stone treatment depends on the size of the kidney stone and the discomfort and symptoms they cause, treatments can range from home management with increased fluids and NSAIDs to hospital-based procedures that remove kidney stones endoscopically or with a minor surgery.
Luckily, kidney stones can be prevented. If you are at risk for developing kidney stones, depending on the type you create, your doctor can give you guidelines for prevention. The most important rule to prevent forming kidney stones is to drink enough water to ensure you are never dehydrated.
+ 5 sources
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- Khan, S.R., Pearle, M.S., Robertson, W., Gambaro, G., Canales, B.K., Steeve Doizi, Olivier Traxer and Hans-Göran Tiselius (2016). Kidney stones. [online] 2(1). doi:https://doi.org/10.1038/nrdp.2016.8.
- Liu, Y., Li, M., Qiang, L.-S., Sun, X., Liu, S. and Tian Jian Lu (2022). Critical size of kidney stone through ureter: A mechanical analysis. [online] 135, pp.105432–105432. doi:https://doi.org/10.1016/j.jmbbm.2022.105432.
- Dasgupta, R., Cameron, S., Aucott, L., MacLennan, G., Kilonzo, M., Lam, T.B., Thomas, R., Norrie, J., McDonald, A., Anson, K., N’Dow, J., Burgess, N., Clark, C.W., Keeley, F.X., MacLennan, S., Starr, K. and McClinton, S. (2022). Shockwave lithotripsy compared with ureteroscopic stone treatment for adults with ureteric stones: the TISU non-inferiority RCT. [online] 26(19), pp.1–70. doi:https://doi.org/10.3310/wuzw9042.
- Hou, J., Zongwei Lv, Wang, Y., Wang, X., Wang, Y. and Wang, K. (2023). Knowledge-map analysis of percutaneous nephrolithotomy (PNL) for urolithiasis. [online] 51(1). doi:https://doi.org/10.1007/s00240-023-01406-w.
- Research and Reports in Urology. (2018). Review of techniques for ultrasonic determination of kidney stone size. [online] Available at: https://www.tandfonline.com/doi/full/10.2147/RRU.S128039.