Kidney stones are hard crystal deposits that form inside the kidney, and when one drops into the narrow tube draining it they cause some of the most severe pain in medicine. They are common: about 11 percent of men and 6 percent of women in the United States have one at some point, according to the National Institute of Diabetes and Digestive and Kidney Diseases. They are also stubborn, because one stone makes another far likelier.
In this article you’ll learn what a stone attack really feels like, including the detail that separates it from other severe abdominal pain, which stone types exist and what drives them, how a stone is confirmed, how stones are treated, and which prevention measures genuinely hold up. It also corrects the most common piece of bad advice about stones: cutting calcium out of your diet.
Read the emergency box below first: fever with flank pain and a suspected stone is not something to wait out at home.
Emergency: when a kidney stone becomes dangerous
Fever or chills together with flank pain and a suspected stone is a urological emergency. A kidney that is both blocked and infected can progress to life-threatening sepsis within hours and needs urgent drainage; antibiotics alone are not enough. Go to the emergency department, or call 911 if you feel very unwell.
Seek emergency care too if:
- You cannot pass any urine at all.
- You are vomiting so much you cannot keep fluids down.
- Your pain is severe and not controlled by what your doctor prescribed.
- You have a single or transplanted kidney and suspect a blockage.
- You are pregnant and have flank pain that might be a stone.
- You feel confused, shivery or clammy, or your heart races.
What a kidney stone is, and the types that matter
Urine carries dissolved minerals and waste. When it becomes concentrated, or the balance between stone-forming substances and natural inhibitors tips, those minerals crystallize and stick together, growing over weeks into a solid mass. Doctors call this nephrolithiasis.
A stone sitting quietly in the kidney often causes nothing. Trouble starts when it enters the ureter, the tube between kidney and bladder, where it can block urine flow and trigger pain. Stone type matters because it dictates prevention: laboratory analysis of a stone you pass is the most useful fact you will ever learn about your own risk.
Calcium oxalate and calcium phosphate stones
Calcium stones are by far the most common, and calcium oxalate outnumbers calcium phosphate. They form when urine carries too much calcium or oxalate, or too little citrate, a natural inhibitor that keeps the two from pairing.
Calcium phosphate stones are likelier when urine runs persistently alkaline, and are more often tied to renal tubular acidosis or an overactive parathyroid gland. Our guide to normal urine pH covers how acidity relates to stone type.
Uric acid, struvite and cystine stones
Uric acid stones form in persistently acidic urine and are linked to gout, insulin resistance, obesity and diets heavy in meat and shellfish. They are the one common type that prescribed treatment can sometimes dissolve.
Struvite stones are infection stones: certain bacteria split urea and alkalinize urine, letting magnesium ammonium phosphate crystallize. They grow fast and follow recurrent infeksi saluran kemih.
Cystine stones are rare and genetic. In cystinuria, an inherited transport defect lets the amino acid cystine leak into urine, where it dissolves poorly; they usually begin young and recur lifelong.
What a kidney stone attack actually feels like
Renal colic, the pain of a stone moving down the ureter, starts abruptly, often at night, and peaks within minutes. It sits in the flank or side of the back below the ribs and radiates forward and down toward the groin, the testicle in men or the labia in women. It arrives in waves, plateauing at an intensity many describe as worse than childbirth. Nausea and vomiting are common, because kidney and gut share nerve pathways.
Here is the detail clinicians use and patients rarely hear: someone with renal colic cannot get comfortable. They pace, writhe and shift position constantly, unable to lie still. That is close to the opposite of peritonitis, the inflamed abdominal lining of a perforated appendix, where movement hurts and people lie rigidly still. Neither pattern proves anything alone, but restlessness with severe one-sided flank pain points strongly toward a stone.
Urine may look pink, red or brown, and microscopic blood is commoner still; our article on darah dalam urin explains why. Once a stone nears the bladder, a constant urge to urinate is typical.
| Situasi | Apa artinya biasanya | Apa yang harus dilakukan? |
|---|---|---|
| Sudden severe flank pain radiating to the groin | Classic renal colic from a stone in the ureter | Urgent same-day assessment for pain control and imaging |
| Flank pain with fever or chills | Possible obstructed and infected kidney | Emergency department now; call 911 if very unwell |
| Stone already diagnosed and passing at home | Expected course for many small stones | Follow your doctor’s plan; strain urine and keep the stone |
| Two or more stones over time | Recurrent stone disease with a treatable underlying cause | Ask about stone analysis and a 24-hour urine evaluation |
| Suspected stone in pregnancy | Higher-risk situation for parent and pregnancy | Same-day obstetric and urology review; ultrasound first |
Who gets kidney stones, and why
The biggest driver is not drinking enough. Concentrated urine gives crystals less water to stay dissolved in, which is why stones are commoner in hot climates and in people whose work makes them sweat heavily, from chefs and roofers to foundry workers, and why attacks cluster in summer.
Diet contributes specifically: high sodium pushes more calcium into urine, heavy animal protein raises acid load and uric acid, and sugar-sweetened drinks track with higher risk.
Several conditions raise risk: obesity, type 2 diabetes, gout, and primary hyperparathyroidism, where an overactive gland drives calcium into the blood and then the urine. Inflammatory bowel disease, chronic diarrhea and bariatric surgery with intestinal bypass cause enteric hyperoxaluria: fat malabsorption leaves free oxalate in the gut to be absorbed and dumped into urine. Hormon paratiroid, blood calcium dan asam urat are the usual tests.
Some medicines contribute, including topiramate, certain HIV protease inhibitors, calcium-based antacids in quantity and long-term diuretics, and family history matters too. Roughly half of people who form one stone form another within about ten years, which is exactly why prevention matters.
Fever with a stone: the emergency that cannot wait
Most stone attacks are miserable but not dangerous. One is different. When a stone blocks a ureter and the urine behind it becomes infected, the kidney turns into a closed, pressurized pocket of pus, forcing bacteria and toxins into the bloodstream. This is obstructive pyelonephritis, and it can progress to septic shock within hours in a previously healthy adult. Fever or shaking chills alongside flank pain is the warning sign.
The answer is not antibiotics alone, because they cannot reach useful concentrations inside an obstructed system. The kidney has to be drained urgently, with a stent passed up the ureter or a nephrostomy tube through the back. Treating the stone itself is postponed until the infection settles.
If you have flank pain and any fever, do not wait to see whether it passes. Get assessed the same day.
How kidney stones are diagnosed
A non-contrast CT scan of the abdomen and pelvis is the reference test. It finds almost every stone, shows size and position, reveals obstruction, and rules out other causes of flank pain.
Ultrasound is often first in pregnancy and in younger patients because it uses no radiation. It is less precise for small ureteric stones but reliably shows swelling of the kidney behind a blockage, usually enough to guide the next step.
Urinalysis is done in nearly every case, looking for red blood cells, signs of infection and crystals; our guide to urine crystals on microscopy explains what those findings do and do not mean. Blood tests usually cover kidney function, calcium and uric acid, and our article on high BUN and creatinine may help you read them.
If a stone is caught, send it for analysis; it is inexpensive and changes prevention completely. For repeated stones, a first stone at a young age, a single kidney or a strong family history, doctors add a metabolic evaluation: a 24-hour urine collection measuring volume, calcium, oxalate, citrate, uric acid, sodium, pH and kreatinin urin, which confirms the collection was complete.
How kidney stones are treated
What follows describes the options; it is not a treatment plan, and every decision belongs to a clinician who has examined you and seen your imaging. Pain control comes first, and the choice of drug depends on your kidney function, other medicines and history. That is why no article should name a painkiller or a dose for you.
Most small stones pass on their own with time, fluids and analgesia. Size and position drive the odds: the smaller the stone and the lower it sits, the better. Your doctor may raise medical expulsive therapy, an alpha blocker that relaxes the lower ureter, generally considered for larger stones in the lower third of the ureter rather than for every stone.
When a stone will not pass, three procedures dominate. Shock wave lithotripsy focuses acoustic energy from outside the body to fragment a stone, needs no incision, and suits smaller kidney and upper ureteric stones. Ureteroscopy passes a fine telescope up through the bladder and breaks the stone with a laser, reaching the whole ureter and kidney with the best chance of clearing it in one session. Percutaneous nephrolithotomy makes a small track through the back into the kidney, for large or staghorn stones.
An obstructed, infected kidney is handled differently: drainage first, stone later.
Preventing the next kidney stone
Prevention is the part of stone care with the best evidence, and one measure stands above the rest: drinking enough to produce a good volume of dilute, pale urine across the day and night. Dilute urine does not easily supersaturate, and crystals cannot grow in what does not supersaturate. Your doctor should set the target volume for you, because it depends on your kidney and heart function and how much you lose through sweat.
Beyond fluid, what holds up is cutting sodium, keeping animal protein moderate, losing excess weight and reducing sugar-sweetened drinks. Restricting oxalate is worth doing only if you form calcium oxalate stones and your 24-hour urine shows high oxalate; blanket avoidance of spinach, nuts and rhubarb helps nobody else.
Some people also need prescribed prevention matched to stone type: thiazide diuretics for high urinary calcium, potassium citrate for low citrate or uric acid stones, allopurinol for high uric acid. These are medicines with real side effects, chosen from your urine results.
The dietary calcium mistake
Here is the correction most articles get backwards: restricting dietary calcium increases the risk of calcium oxalate stones. It does not reduce it.
The reason is mechanical. Calcium eaten with a meal binds oxalate inside the gut, forming a compound that is not absorbed and leaves in the stool. Remove the calcium and that oxalate is absorbed instead, reaches the kidney and is excreted into urine, free to pair with calcium and crystallize. As the National Institute of Diabetes and Digestive and Kidney Diseases states, calcium from food does not increase your chance of having calcium oxalate stones, and in the right amounts calcium blocks other substances in the digestive tract that lead to stones (NIDDK, Eating, Diet and Nutrition for Kidney Stones).
Calcium supplements are a separate question. Taken with food they behave much like dietary calcium; taken between meals, with no oxalate to bind, the extra calcium is absorbed and raises urinary calcium instead. If you take calcium or vitamin D supplements and form stones, discuss it with your doctor.
Lemon juice, apple cider vinegar and stone cleanses
Citrate is not folklore. It genuinely inhibits stone formation by binding calcium in urine and interfering with crystal growth, which is why potassium citrate is a prescription medicine. Lemons are rich in citrate, and small studies of lemonade therapy have shown modest rises in urinary citrate in some patients. It is a reasonable, low-cost thing to raise with your doctor, and nothing more.
What lemon juice does not do is dissolve a calcium stone. Nothing you can drink does. The only stones dissolved medically are uric acid and some cystine stones, and that is done by a doctor alkalinizing your urine with prescribed medication and monitoring the result.
Apple cider vinegar has no clinical evidence behind it in stone disease. Commercial kidney cleanses and stone-flushing protocols have none either, and some contain high-oxalate ingredients or diuretic herbs that make matters worse. Recent evidence reviews also flagged more minor side effects with lemon juice than with placebo. Treat these as unproven, and treat a suspected stone as a medical problem.
Latest scientific advances in kidney stone care
A federally funded evidence review published in Annals of Internal Medicine in 2026 by Asher and colleagues pooled 31 studies on preventing recurrent stones. It found that increased water intake, and a diet with normal to high calcium plus low protein and low sodium, may reduce recurrence, alongside thiazides, alkali therapy and allopurinol, though the certainty of evidence was low throughout. It also linked lemon juice to more minor adverse events. What this means for you: fluid and diet remain the best-supported things you can do, and normal calcium is part of that advice, not an exception.
The NOSTONE trial, published in the New England Journal of Medicine in 2023 by Dhayat and colleagues, tested hydrochlorothiazide against placebo in people with recurrent calcium stones. Across three doses and nearly three years of follow-up, recurrence was not meaningfully different from placebo, while low potassium, new gout and new diabetes were commoner on the drug. What this means for you: a thiazide is no longer an automatic prescription, and it is fair to ask why one was chosen for your urine profile.
A 2024 review in Current Opinion in Nephrology and Hypertension by Bargagli and colleagues added a meta-analysis of every placebo-controlled trial of thiazide monotherapy, found no significant advantage, and argued for restrained use. What this means for you: prevention is shifting toward treatment matched to your measured urine chemistry rather than applied to everyone.
A 2025 systematic review and meta-analysis in European Urology Focus by Nedbal and colleagues, from the European Association of Urology endourology section, compared flexible ureteroscopy with shock wave lithotripsy in a very large pooled population. Ureteroscopy cleared stones more often and needed repeat treatment less often, with comparable complications, hospital stay and cost. What this means for you: if both are offered, ask how likely each is to clear your stone in a single session, not just which sounds less invasive.
Finally, a 2025 hospital study in BMC Urology by Hsu and colleagues followed people admitted with sepsis from an obstructing upper ureteric stone. Those given emergency drainage early reached definitive treatment sooner and left hospital sooner. What this means for you: it reinforces the box at the top, that an infected, blocked kidney is drained first and the stone dealt with afterwards.
Daftar istilah kunci
| Ketentuan | Definisi |
|---|---|
| Renal colic | The wave-like pain caused by a stone moving down the ureter, felt in the flank and radiating to the groin. |
| Ureter | The narrow tube carrying urine from each kidney to the bladder, and the usual place a stone gets stuck. |
| Nephrolithiasis | The medical name for kidney stone disease. |
| Oksalat | A compound in some plant foods that binds calcium; too much of it in urine drives the commonest stone type. |
| Citrate | A natural inhibitor in urine that binds calcium and slows crystal growth; low levels raise stone risk. |
| Hidronefrosis | Swelling of the kidney caused by urine backing up behind a blockage. |
| Shock wave lithotripsy | A procedure that fragments a stone with focused acoustic energy delivered from outside the body. |
| Ureteroscopy | A procedure passing a fine telescope up the urinary tract to break or remove a stone with a laser. |
| Percutaneous nephrolithotomy | Removal of a large stone through a small track made through the back into the kidney. |
| 24-hour urine collection | A full day of urine collected and analyzed to find the metabolic cause of recurrent stones. |
Pertanyaan yang sering diajukan
How long does it take to pass a kidney stone?
It depends mostly on size and position, and nobody can promise a stone will pass at all. Very small stones low in the ureter often clear within a week or two; larger ones may take several weeks, and stones above a certain size usually need a procedure. Doctors normally set a limit on how long they are willing to watch and wait, because a ureter blocked for too long can damage the kidney behind it. If your pain worsens, you develop a fever, or nothing has happened within the window your doctor gave you, go back sooner rather than later.
Should I cut out calcium if I get kidney stones?
No, and this is the single most common mistake. A low-calcium diet increases the risk of calcium oxalate stones, because dietary calcium binds oxalate in the gut so it leaves in the stool instead of reaching your urine. Take the calcium away and more oxalate is absorbed and excreted, which is exactly the wrong direction. Normal dietary calcium is protective, and it also protects your bones. Calcium supplements are a different matter: taken away from food they can raise urinary calcium, so ask your doctor before starting or stopping one.
Does lemon juice dissolve kidney stones?
No. Nothing you drink dissolves a calcium stone. The grain of truth is that citrate, which lemons contain in quantity, genuinely inhibits stone formation, and potassium citrate is a real prescription preventive. Small studies of lemonade therapy have shown modest rises in urinary citrate in some patients, so it is worth raising with your doctor as a low-cost addition to fluid intake. It is not a treatment for a stone you already have, and a recent evidence review found lemon juice regimens caused more minor side effects than placebo.
Can a kidney stone damage my kidney?
Usually not, if it is dealt with in reasonable time. The risk comes from prolonged obstruction and from infection. A ureter blocked for weeks can cause lasting loss of function in that kidney, and an obstructed kidney that becomes infected is a medical emergency. People with a single kidney, a transplanted kidney or existing kidney disease have less margin and are treated more urgently. That is why the advice is always to get a suspected stone assessed rather than to tough it out.
Should I catch the stone, and what happens to it then?
Yes. Strain your urine through the filter your clinic provides, or a fine mesh, and keep anything solid, even if it looks like a grain of sand. The laboratory analyzes what it is made of, and that result shapes your whole prevention plan: oxalate advice for one type, urine alkalinization for another, infection control for a third. Being pain free does not prove the stone has passed, so follow-up imaging is often arranged as well.
Can I have a kidney stone if my urine test is normal?
Yes. Most people with renal colic have blood in the urine, but a meaningful minority do not, particularly when a stone completely blocks the ureter. A normal urinalysis therefore does not rule a stone out, and imaging settles the question. The reverse is also true: blood in the urine has many causes besides stones, so that finding alone does not confirm one either.
Sumber
Study details and citations were retrieved from PubMed.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) – Definition & Facts for Kidney Stones
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) – Eating, Diet, & Nutrition for Kidney Stones
- MedlinePlus, U.S. National Library of Medicine – Kidney stones
- American Urological Association – Medical Management of Kidney Stones clinical guideline
- Asher GN, Viprakasit DP, Aymes SE, Lusk JB, Ross S, Baker C, Rains C, Wright ST, Kahwati LC. Prevention of Recurrent Nephrolithiasis in Adults and Children: A Systematic Review. Ann Intern Med. 2026;179(5):696-707. https://doi.org/10.7326/ANNALS-25-04452
- Dhayat NA, Bonny O, Roth B, Christe A, Ritter A, Mohebbi N, et al. Hydrochlorothiazide and Prevention of Kidney-Stone Recurrence. N Engl J Med. 2023;388(9):781-791. https://doi.org/10.1056/NEJMoa2209275
- Bargagli M, Trelle S, Bonny O, Fuster DG. Thiazides for kidney stone recurrence prevention. Curr Opin Nephrol Hypertens. 2024;33(4):427-432. https://doi.org/10.1097/MNH.0000000000000990
- Nedbal C, Geraghty R, Tramanzoli P, Sessa D, Gauhar V, Galosi AB, Gregori A, Somani BK. Cost and Effectiveness of Flexible Ureteroscopy Versus Shockwave Lithotripsy for Urolithiasis: A Systematic Review and Meta-analysis by the European Association of Urology Endourology Section. Eur Urol Focus. 2025;11(6):1012-1022. https://doi.org/10.1016/j.euf.2025.06.004
- Hsu JT, Lin CM, Hung SF, Chung SD, Cheng PY. Optimizing antibiotic duration and percutaneous nephrostomy timing in urosepsis complicated by upper ureteral stones: a retrospective study. BMC Urol. 2025;25(1):182. https://doi.org/10.1186/s12894-025-01868-7
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A stone workup usually produces several numbers at once: a urinalysis, creatinine and kidney function, blood calcium and uric acid, and later a 24-hour urine collection. AI DiagMe reads those results and explains in plain language what each one measures and why your doctor ordered it. It helps you understand your results and prepare better questions. It does not diagnose kidney stones and does not replace your doctor.
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