Bladder stones, also called vesical stones or urolithiasis, are hard mineral deposits that form inside the urinary bladder. They often develop when urine stays in the bladder for too long, giving minerals time to crystallize. Small stones may pass out of the body without being noticed, but larger ones can cause strong pain, difficulty urinating, and other unpleasant symptoms. This article clearly explains how bladder stones form, what causes them, how to prevent them, and what treatment options exist, so you can better understand and manage this condition.
Bladder stones make up about 5% of all urinary stones, yet in developed countries they are responsible for around 8% of deaths linked to urolithiasis. They are more common in developing countries and occur far more often in men, with a male-to-female ratio between 10:1 and 4:1. There are two age peaks: in children around three years old in developing regions, and in adults around 60 years of age.
What Is a Bladder Stone (Urolithiasis)?
Bladder stones are basically hardened lumps of minerals that form in the bladder. These crystal formations develop when substances in the urine, such as salts, potassium, and protein waste products, come out of solution and stick together. This usually happens if the bladder does not empty completely when you urinate and urine stays behind, allowing minerals to build up and form crystals.
The term urolithiasis more broadly means stones anywhere in the urinary tract, including the kidneys, ureters, and bladder. Bladder stones are one special group inside this wider category, with their own typical causes and symptoms. It is important to separate kidney stones from bladder stones, because even if they are made of similar materials, they often form for different reasons and may need different treatment.
How a Bladder Stone Forms
The starting point for bladder stone formation is an overload of minerals in the urine and their crystallization. Normally, urine keeps these minerals dissolved. If the urine becomes too concentrated – for example due to drinking too little fluid or because the bladder does not empty well – minerals start to form crystals. These tiny crystals then clump together and slowly grow into larger stones. This process can be speeded up by urinary tract infections, foreign bodies (like catheters), or structural problems of the bladder that promote urine stagnation.
Changes in urine pH also play a role. For instance, a lower pH (more acidic urine) favors formation of uric acid stones. Some metabolic disorders can also increase the chance of forming stones, although specific metabolic changes linked only to bladder stones have been studied less.
Main Types of Bladder Stones
Bladder stones can be grouped into three main categories: primary, secondary, and migratory stones.
- Primary or endemic bladder stones: These form without any other urinary tract disease, mostly in children in areas with poor hydration, frequent diarrhea, and diets low in animal protein.
- Secondary bladder stones: These appear in the presence of other urinary problems, such as bladder outlet obstruction (BOO), neurogenic bladder, chronic bacteriuria, foreign bodies (like catheters), bladder diverticula, bladder enlargement surgery, or urinary diversion. In adults, BOO is the most common factor and is found in 45-79% of bladder stone cases.
- Migratory bladder stones: These stones start in the upper urinary tract (usually the kidneys), then move down into the bladder, where they may continue to grow. Their presence often points to conditions that also favor upper urinary tract stones.
The chemical makeup of stones can differ. In one study, bladder stones linked to benign prostate obstruction (BPO) were 42% calcium-based (oxalate or phosphate), 33% magnesium-ammonium-phosphate, 10% mixed, and 14% uric acid. Uric acid stones do not show up on standard X-rays (they are radiolucent) and are usually seen with ultrasound.
What Causes Bladder Stones?
Bladder stones rarely have a single cause. Most often several factors act together. As already mentioned, urine stagnation in the bladder is one of the main triggers, because it allows minerals to concentrate and form crystals. But what leads to this stagnation, and what other factors play a part?
Finding the underlying causes is key to successful treatment and to lowering the chance of stones coming back. For this reason, when making the diagnosis, the doctor takes a detailed medical history and orders tests to identify each patient’s personal risk factors.
Bladder Outlet Obstruction
Bladder outlet obstruction (BOO) is one of the most frequent and important causes of bladder stones, especially in adult men. The obstruction prevents the bladder from emptying fully, leading to urine stagnation. In this trapped urine, minerals can easily precipitate and form stones.
In men, benign prostatic hyperplasia (BPH, non-cancerous enlargement of the prostate) is common with increasing age. The enlarged prostate can press on the urethra and partly block it. This is the main cause of BOO and is present in 45-79% of men with bladder stones. A larger part of the prostate bulging into the bladder (intravesical protrusion) is an independent risk factor for stone formation in BPH patients. Older age and lower maximum urine flow (Qmax) also predict bladder stone formation.
Urethral strictures, bladder diverticula (outpouchings of the bladder wall that trap urine), and bladder prolapse (cystocele) can also contribute to BOO and stone formation by blocking or slowing urine flow and giving crystals time to settle.
Role of Infections
Chronic bacteriuria, meaning long-lasting urinary tract infections, can strongly promote bladder stone formation. Some bacteria, especially urea-splitting species such as Proteus mirabilis, break down urea in the urine into ammonia and carbon dioxide. This reaction raises urine pH, making it more alkaline, which favors formation of magnesium-ammonium-phosphate (struvite) stones, often called infection stones.
Repeated urinary tract infections (UTIs) can sometimes be the only sign of a bladder stone, so treating infections properly and finding their cause is very important. Infections also cause inflammation of the bladder wall, which further supports stone formation.
Other Common Causes
Besides BOO and infections, several other factors can support bladder stone formation:
- Nerve damage (neurogenic bladder): Spinal cord injury, stroke, Parkinson’s disease, diabetes, or other nerve problems can damage the nerves that control the bladder. This may lead to incomplete emptying, urine retention, and stone formation. People with long-term indwelling catheters have a much higher risk of stones.
- Foreign bodies: Any foreign material in the bladder – catheters, surgical clips, sutures – can act as a “seed” for mineral deposits and later stones.
- Bladder augmentation or urinary diversion: Surgeries that enlarge the bladder or reroute urine flow using bowel segments increase stone risk. Reasons include higher mucus production, poor bladder emptying, or bacterial overgrowth.
- Dehydration: Drinking too little fluid makes urine more concentrated, which encourages mineral precipitation and stone formation. Urine should be clear or light yellow; dark yellow urine suggests that fluid intake is too low.
- Migratory kidney stones: Although kidney and bladder stones usually form under different conditions, a small kidney stone can travel to the bladder and then grow there into a bladder stone.
- Diet: While metabolic disorders are less clearly linked to bladder than to kidney stones, uric acid stone formation can be related to a diet high in purines (legumes, fish, meat extracts) and low urine pH.
How Can Bladder Stones Be Prevented?
Prevention is especially important in people who are prone to stones or have had them before. Because bladder stones often relate to poor bladder emptying and changes in urine composition, prevention focuses mainly on lifestyle changes and treatment of underlying conditions. Complete prevention is not always possible, but the risk can usually be reduced a lot.
Main preventive steps include proper fluid intake, a balanced diet, and control of personal risk factors. The most important points are explained below.
Fluids and Lifestyle Advice
Drinking enough fluids is one of the simplest and most effective ways to reduce bladder stone risk. Plenty of fluid, especially water, dilutes minerals in the urine so they are less likely to form crystals and stones. A daily intake of at least 2.5-3 liters of fluid, mostly water, is usually advised so that daily urine output reaches about 2.5 liters. This helps flush out materials that could form stones.
Watching urine color is a practical guide: it should be clear or pale yellow. Dark yellow urine usually means not enough fluid. Other lifestyle tips include avoiding prolonged or severe diarrhea, which can cause dehydration, and regular bladder irrigation in people with bladder enlargement surgery or neurogenic bladder. For patients with long-term indwelling catheters, regular irrigation and careful catheter care are very important.
Role of Proper Nutrition
Diet has a strong effect on stone risk. A general recommendation is a balanced diet rich in vegetables and fiber. Very high salt intake and large amounts of animal protein should be avoided, as they may increase stone risk. Strong restriction of dietary calcium is not recommended, because it can increase oxalate absorption in the gut and actually promote stone formation, and it may also harm bone health.
Drinks with high fructose content should be limited, because they may raise stone risk. People with a tendency to form uric acid stones should reduce, but not necessarily completely avoid, purine-rich foods (legumes, fish, meat extracts). In children, especially where primary (endemic) bladder stones are a problem, good hydration, prevention of diarrhea, and a mixed cereal-based diet with milk and vitamins A and B are advised. After one year of age, adding eggs, meat, and boiled cow’s milk is also recommended.
Reducing Risk Factors
Controlling underlying conditions is one of the main pillars of prevention. In men over 50, treatment of benign prostatic enlargement (BPH) is very important, because it often causes BOO and urine retention. Doctors may use medication or surgery to shrink the prostate or widen the urinary passage and improve urine flow.
In people with neurogenic bladder, methods that help better empty the bladder, like clean intermittent self-catheterization (CISC) or regular bladder irrigation, can reduce stone risk. Careful treatment and prevention of chronic urinary tract infections are also key, since they support stone formation. Medical devices such as catheters must be changed regularly and handled correctly to reduce mineral buildup.
Obesity is another known risk factor, so keeping a healthy body weight with a normal-calorie diet can also help. Patients at high risk of recurrence (multiple recurrences, a single functioning kidney, children under 16 with kidney stones) should see a specialist in stone prevention.
Which Treatments Are Available for Bladder Stones?
Treatment depends mainly on stone size, number, composition, and the causes behind them. Because a bladder stone almost always points to another underlying problem, it is usually necessary to both remove the stone and treat the cause to keep stones from coming back. Options range from medication to several minimally invasive methods and open surgery.
The main goals are: complete stone removal, relief of symptoms, and prevention of long-term problems such as infections or urinary blockage. The main treatment methods are described below.
When Is Active Stone Removal Needed?
Active stone removal is almost always needed for primary and secondary bladder stones, because they usually cause symptoms and are unlikely to pass on their own. Symptoms may include frequent urination, blood in the urine (often at the end of urination), pain when passing urine, or lower abdominal (suprapubic) pain that gets worse at the end of urination. In children, signs can include pulling at the penis, difficulty starting to urinate, urinary retention, bedwetting, and rectal prolapse.
On the other hand, small, symptom-free migratory bladder stones in adults can sometimes be left without treatment, especially if there is no BOO, no bladder dysfunction, and no long-term catheter. If the stone grows or starts to cause symptoms, active removal becomes necessary. The only clear reason not to remove a stone is a severely ill or terminal patient who has no symptoms from the stone.
Medication Options
There is limited evidence for treating bladder stones with drugs alone. The only medical approach with some proven effect is dissolving uric acid stones by making the urine more alkaline. This can work if urine pH is kept above 6.5 using alkaline citrate or sodium bicarbonate. Regular monitoring is needed during this therapy, because over-alkalinization can cause calcium phosphate to deposit on the stone surface, making further dissolution impossible.
Other solutions, such as Suby G or M, are used rarely. Renacidin can be used to dissolve phosphate or struvite stones, but treatment is slow and invasive because it needs long-term irrigation through indwelling catheters, and close monitoring for signs of sepsis or high magnesium levels. For small stones that may pass on their own, alpha-blockers can be used to make urination easier, though this is more common in kidney stone treatment.
Types of Surgical Procedures
Several surgical techniques are available for removing bladder stones, and minimally invasive options are used more and more to lower complication rates, shorten hospital stay, and speed up recovery. These include transurethral, percutaneous, laparoscopic methods and extracorporeal shock wave lithotripsy (ESWL).
Transurethral Cystolithotripsy in Adults
In transurethral cystolithotripsy (TUC), the surgeon passes an endoscope (cystoscope) through the urethra into the bladder, locates the stone, and breaks it into small pieces using mechanical, ultrasonic, electrohydraulic, or laser energy. The fragments are then washed out or removed through the scope.
In adults, this method achieves high stone-free rates and is considered safe, with low rates of unplanned procedures and serious complications. Compared to percutaneous cystolithotripsy, TUC usually means shorter hospital stay, quicker recovery, and less pain, with similar success and complication rates. Using continuous-flow instruments (nephroscope or resectoscope) can make the procedure faster than with a standard cystoscope.
Transurethral Cystolithotripsy in Children
TUC can also be used in children, but because the child’s urethra is narrower, special smaller instruments are needed. With modern equipment, this method is possible in selected pediatric cases. Three non-randomized studies showed that in children, TUC leads to shorter hospital stay and catheter time than open cystolithotomy, with similar stone-free and complication rates.
However, in children the transurethral approach may take longer and can carry a higher risk of postoperative urethral stricture. For small stones under 1.5 cm, both laser and pneumatic lithotripsy are effective; pneumatic methods may have slightly fewer minor complications.
Suprapubic Cystolithotomy
Open suprapubic cystolithotomy is a classic surgical technique. The surgeon makes an incision through the lower abdominal wall, opens the bladder directly, and removes the stones whole, instead of breaking them. This approach is very effective but usually requires longer catheterization and hospital stay than endoscopic procedures in both adults and children.
It is most often used for very large or very hard stones, or if an open prostatectomy or removal of bladder diverticula is also needed. Advantages include quick removal, the ability to remove multiple stones at once, and easier removal of stones stuck to the bladder wall or stones too large and hard for transurethral or percutaneous methods. Disadvantages are more postoperative pain, longer hospital stay, and longer catheter time.
Percutaneous Cystolithotripsy
In percutaneous cystolithotripsy, the surgeon makes a small incision in the lower abdomen and passes an endoscope directly into the bladder. This method allows shorter, larger-diameter instruments, which can speed up stone fragmentation and removal. In children, this is often the first choice.
In adults, a meta-analysis showed that percutaneous cystolithotripsy comes with longer hospital stay, slower recovery, and more pain than the transurethral approach, though success and complication rates are similar. In male adults with urethral stricture, one study found that percutaneous surgery led to shorter operating time and catheterization and less blood loss compared with open surgery.
Extracorporeal Shock Wave Lithotripsy (ESWL)
ESWL is the least invasive method to treat bladder stones. Shock waves generated outside the body are focused on the stone to break it into smaller pieces, which then pass out in the urine. ESWL is widely used for kidney stones but is less often used for bladder stones.
In one randomized trial of stones under 2 cm, after a single session the stone-free rate was lower with ESWL than with transurethral cystolithotripsy (86% vs. 98%). After up to three ESWL sessions, the results became similar (94% vs. 98%). Hospital stay was shorter with ESWL. In children, ESWL gave lower stone-free rates than endoscopic or open surgery even for small stones.
Laparoscopic Cystolithotomy
Laparoscopic cystolithotomy in adults is usually done together with simple prostatectomy, using standard or robot-assisted laparoscopy. Through several small incisions, the surgeon introduces a camera and instruments to remove the stones. There are few direct comparisons with other techniques, but in selected cases it can be a useful minimally invasive option.
Surgery in Patients With Bladder Outlet Obstruction
In men over 40 with bladder stones, benign prostatic obstruction (BPO) is often the main underlying problem, so prostate treatment must be considered too. In the past, bladder stones by themselves were considered a clear reason to operate on BPO, but this view has changed.
When treating BPO and bladder stones together, surgeons may remove the stones and in the same session perform transurethral resection of the prostate (TURP) or transurethral incision of the prostate (TUIP). It is important to destroy or remove the stone before treating the prostate to lower the risk of bleeding and excessive fluid absorption. Large studies show that operating on BPO and stones at the same time is safe and does not increase serious postoperative complications compared with BPO surgery alone, although short-term incontinence and UTI rates may be slightly higher.
Special Situations in Bladder Stone Management
Certain conditions and operations greatly increase the risk of bladder stones and need special attention for both prevention and treatment. These include neurogenic bladder and patients who have had bladder augmentation or urinary diversion.
In these cases, standard treatment plans often need to be adjusted to the patient’s underlying disease and previous surgeries. Care from several specialists working together is often needed for the best outcome.
Neurogenic Bladder and Stone Formation
Neurogenic bladder, most often caused by spinal cord injury or myelomeningocele, carries a high risk of bladder stones. Between 15-36% of patients with spinal cord injury develop bladder stones within 8-10 years. The rate depends on the level and completeness of the injury: 19-39% in those with motor-incomplete injury and 36-67% in those with motor-complete injury over time.
Among spinal cord-injured patients with indwelling catheters, the absolute yearly risk of bladder stones is about 4%, compared with 0.2% in those using intermittent self-catheterization. In one study, people with long-term urethral catheters were six times more likely to form bladder stones than those with normal voiding. After complete stone removal, the yearly recurrence risk is about 16%. Regular bladder irrigation, for example manual flushing twice a week, can greatly lessen stone formation and symptomatic UTIs in these patients.
Bladder Augmentation and Urinary Diversion
Bladder augmentation enlarges the bladder, usually by adding a piece of bowel, to improve storage. A common side effect, however, is a much higher risk of bladder stones. In adults, reported rates range from 2-44%, and in children from 4-53%. Stones usually appear 24-31 months after surgery in adults and 25-68 months in children.
Risk factors include high mucus production, incomplete bladder emptying, failure to follow advice about CISC or bladder irrigation, bacteriuria or UTIs with urea-splitting bacteria, and foreign materials (clips, meshes, non-absorbable sutures). People using CISC instead of normal voiding are also at higher risk. Stomach-segment augmentations seem to carry lower stone risk than ileal or colonic segments. In patients with a previous stone, recurrence rates are 15-44% in adults and 19-56% in children.
Urinary diversions, such as ileal or colonic conduits, also increase stone risk, though reported rates are lower (0-3%). In orthotopic ileal neobladders, rates vary from 0-34%; in sigmoid neobladders, 4-6%. The average time between surgery and stone detection is 71-99 months. Regular irrigation with saline, daily or about three times a week, lowers stone risk after augmentation or continent urinary diversion.
Stone Removal in Augmented Bladder or After Diversion
In patients with an augmented bladder or urinary diversion, stones can be removed with open or endoscopic surgery. Often the stone cannot be reached safely through a continent vesico-enteric stoma without harming the continence mechanism, so percutaneous or open approaches are preferred.
Two observational studies showed that percutaneous lithotomy under ultrasound or CT guidance can be done safely in patients with reconstructed or augmented bladders. The benefits are similar to those seen with percutaneous surgery in a normal bladder when compared with open surgery. After successful removal, recurrence rates range from 10-42%, and this seems unrelated to the method used for stone removal.
After Bladder Stone Treatment: What to Watch For
Stone removal is only part of the process. The period after treatment is just as important, because this is when we find out whether stones will stay away and whether the patient will fully recover. Follow-up visits, lifestyle changes, and any needed additional therapies help the patient return to normal life and lower the chance of future problems.
Follow-up does not just check if the patient is stone-free, but also seeks and treats the root causes of stone formation. This is very important for lowering recurrence rates. The main points for the post-treatment period are described below.
Check-Ups and Follow-Up
Typical follow-up after bladder stone treatment is at 3-4 weeks, using a kidney-ureter-bladder (KUB) X-ray or bladder ultrasound to confirm that no fragments remain. Because there is little strong data on the best follow-up schedule or tests, the plan should be tailored to each patient.
Important factors are whether the underlying functional cause has been treated (for example, TURP for BPO) and the metabolic risk. Patients with uric acid stones, upper urinary tract stones, strong family history of stone disease, stones without obstruction, or repeated stones should have a metabolic stone workup. KUB X-rays can then be done every 6-12 months if needed. Studies about the link between bladder stones and later bladder cancer give mixed results, so regular cystoscopy for this reason alone is still debated.
Recovery Time and Return to Daily Activities
Most people recover from cystolithotripsy or open surgery within one to two weeks. Small bladder stones that pass on their own may cause little or no symptoms. After treatment, many patients can go back to work, school, and normal activities within a few days, but they should follow their doctor’s advice and avoid heavy physical effort until fully healed.
Plenty of fluids and a healthy lifestyle remain important even after treatment to lower the risk of new stones. If the underlying cause of the bladder stone is not treated, stones are likely to come back. With correct treatment of both the stones and the cause behind them, bladder stones usually do not lead to long-term health problems.
Szólj hozzá