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Bladder stones are solid calculi that are formed primarily in the urinary bladder. Although bladder stones usually occur in individuals with urinary stasis, such as benign prostatic hyperplasia or neurogenic bladder, these can also form in healthy individuals. Bladder stones are usually calcified but may also consist of non-calcific material, such as uric acid. The incidence of bladder stones is relatively low in Western countries but higher in developing countries, particularly in the Middle East, North Africa, and parts of Asia, largely due to dietary factors. Symptoms include discomfort, and diagnosis typically involves urinalysis, imaging (x-ray, computed tomography, or ultrasound), and cystoscopy. Treatment includes medical therapy with oral alkalinizing agents such as potassium citrate along with surgical management options, often involving endoscopic surgery. Addressing underlying conditions is crucial for effective management. This activity explores the evaluation and management of bladder stones, emphasizing diagnostic methods, treatment strategies, and the importance of addressing underlying causes to prevent recurrence. This activity highlights the importance of interprofessional collaboration among healthcare providers to improve patient outcomes through accurate diagnosis, appropriate medical or surgical intervention, and the correction of contributing factors such as urinary stasis. Objectives: Identify risk factors contributing to bladder stone formation, including urinary stasis and dietary influences. Screen at-risk populations, including patients with benign prostatic hyperplasia or neurogenic bladder, for early detection. Select the most effective intervention, such as medical therapy, endoscopic surgery, or open procedures, based on stone size, composition, and patient factors. Collaborate with interprofessional healthcare providers to optimize patient care and ensure adherence to treatment strategies, thereby reducing the risk of recurrence. Access free multiple choice questions on this topic.

Bladder stones are solid calculi primarily found in the urinary bladder. Although bladder stones are often calcified, they may also consist of non-calcific material (see Image. A Bladder Calculus).[1][2][3][4] The incidence of bladder stones is relatively low in Western countries but higher in developing countries, primarily due to dietary factors. The regions most affected include countries in the Middle East, North Africa, Thailand, Indonesia, and Myanmar. Please see StatPearls' companion resource, "Ultrasound of the Urinary Tract," for more information. Bladder stones account for about 5% of all urinary stones and usually occur due to urinary stasis, as seen in conditions such as benign prostatic hyperplasia (BPH) or neurogenic bladder. However, they can also form in healthy individuals without anatomical defects, foreign bodies, strictures, or infections.[5][6] The presence of upper urinary tract calculi does not necessarily increase the risk of bladder stone formation. Bladder stones cause specific symptoms and are a significant source of patient discomfort.

Urinary stasis, such as that seen in BPH or neurogenic bladder disorder, is the primary cause of bladder calculi.[5] Most of these stones are newly formed in the bladder, although some may originate in the kidneys as a calculus or a sloughed papilla. Stones from the kidneys that are small enough to pass through the ureters can easily travel through the urethra unless there is significant bladder dysfunction or outlet obstruction. Stones that remain in the bladder will develop additional concentric layers of material, which may or may not be identical to the original core material.[7][8][9] Bladder outlet obstruction, most commonly due to BPH, is the leading risk factor for bladder stones, accounting for 45% to almost 80% of such cases.[10][11][12][13][14] Among men undergoing surgical treatment for BPH, 3% to 4.7% develop bladder stones.[15][16] Please see StatPearls' companion resource, "Cystinuria," for more information. Any nonabsorbable foreign body left in the bladder that is not spontaneously expelled will eventually develop layers of stone material and form calculus. An example of this would be a surgical staple or permanent suture left exposed inside the bladder. This is why absorbable suture material is recommended for urinary surgeries. A retained double pigtail stent can also form stone material if left in the urinary tract for a prolonged period. Another example is a fragment from a Foley catheter balloon that "fell out" after a balloon rupture, with a retained fragment left in the bladder. For this reason, it is important to inspect any Foley catheter that has been forcibly extracted or "fallen out" to ensure no balloon fragments are missing, as they could develop into stones. If this inspection is not possible or there is concern about a retained fragment, cystoscopy should be performed to remove any intravesical balloon fragments. Foley catheters are associated with a higher incidence of bladder stones compared to intermittent catheterization. In a study of patients with spinal cord injuries, 36% developed bladder calculi over an 8-year follow-up period. However, improved urologic care significantly reduced the bladder stone formation rate to approximately 10%.[17]

Foley catheters are associated with a higher incidence of bladder stones compared to intermittent catheterization. In a study of patients with spinal cord injuries, 36% developed bladder calculi over an 8-year follow-up period. However, improved urologic care significantly reduced the bladder stone formation rate to approximately 10%.[17] Radiation therapy, schistosomiasis, bladder augmentation surgery, urethral strictures, neurogenic or hypotonic bladder dysfunction, and bladder diverticula are additional risk factors for bladder stone formation. Up to two-thirds of patients with spinal cord injuries develop bladder stones.[18] In children, risk factors for bladder stones include chronic or recurrent diarrhea, inadequate hydration, and protein-deficient diets.[19][20][21] Such predisposing conditions are commonly found in developing countries.[19] The most frequent laboratory finding in these children is low urinary volume, followed by hypocitraturia.[21][22][23] Neurogenic bladder, spinal cord injury, continent urinary diversions, and bladder augmentation surgery are well-established risk factors for bladder stone formation. Patients with neurogenic bladder requiring permanent indwelling catheters due to spinal cord injury are 6 times more likely to develop bladder stones than individuals who void normally.[24][25] Up to two-thirds of spinal cord–injured patients with neurogenic bladders will experience bladder stone formation.[18] The annual recurrence rate of bladder stones in spinal cord–injured patients with neurogenic bladders is 16%.[26] Over 20 years, more than 40% of patients with augmented bladders develop stones.[27][28] Bladder irrigation performed daily or 3 times weekly has been shown to reduce the incidence of bladder stones in augmented bladders and continent urinary diversions.[29][30][31] In contrast, standard ileal conduit surgery is associated with a significantly lower stone formation rate, not exceeding 3%.[31][32]

The overall incidence of bladder stones in adults appears to be decreasing in developed countries, likely due to the widespread use of BPH medications such as alpha-blockers and 5-alpha reductase inhibitors (5-ARIs). Bladder stones are more common in males than females, particularly in males aged 50 or older, with a male-to-female prevalence ratio ranging from 4:1 to 10:1.[10] Stones larger than 100 grams in size are rare and predominantly occur in males.[33] In general, adult men with BPH and bladder stones are more likely to have a history of nephrolithiasis, gout, lower urinary pH, and lower urinary magnesium levels compared to men with BPH who do not have bladder calculi. The presence of urinary tract infections (UTIs) and significant intravesical prostatic extension (BPH) are the clinical signs most strongly associated with the development of bladder calculi.[34] In children, the overall incidence of bladder stones is also decreasing, primarily due to improved prenatal and postnatal care, as well as a general improvement in neonatal nutritional support. Boys typically have more bladder stones than girls, and these stones are not associated with unrelated urolithiasis. Recurrences of bladder stones are relatively uncommon in children, in contrast to pediatric renal stone disease, where recurrences are more frequent. Most cases of pediatric bladder stones occur in children between the ages of 2 and 5.[35] The peak incidence of bladder stones occurs at age 3 in children and 60 in adults.

Uric acid is the most common composition of bladder stones in adults, accounting for about 50% of cases. Most patients with uric acid bladder stones do not have gout or hyperuricemia. Risk factors for uric acid bladder stones include low urinary pH, dehydration, hyperuricosuria, and uric acid nephrolithiasis. Other substances that can form bladder stones include calcium oxalate, calcium phosphate, ammonium urate, cystine, and calcium-ammonium-magnesium phosphate (also known as triple phosphate or struvite stones, which are always associated with infection). Patients prone to chronic bacteriuria and urinary infections, such as those with spinal cord injuries or severely hypotonic bladders, are more likely to develop struvite (infection-related or triple phosphate) and calcium phosphate stones.[36] Stones composed primarily of calcium oxalate or calcium phosphate typically begin as renal calculi, becoming trapped in the bladder. Over time, they develop additional layers of stone material until they grow too large to pass, causing symptoms in the patient. Jackstones are a rare form of bladder calculi, visually resembling larger versions of children's jacks, with crossing X-shaped structures joined at a central nidus. They consist of a protein-rich, radiolucent core surrounded by multiple concentric layers of hard calcium oxalate monohydrate. Care must be taken during removal to avoid injuring the patient.[37] An association between bladder calculi and cancer of the urinary bladder has been suggested, although this remains a controversial and unresolved issue.[38][39][40][41] In children, the most common types of bladder stones are calcium oxalate, calcium phosphate, and possibly ammonium acid urate. In developing countries, infants and young children are often fed only breast milk and rice, which can lead to high urinary ammonia excretion due to low dietary phosphorus. These children also tend to have a high intake of green vegetables (which increases dietary oxalate) and low dietary citrate.[42]

Bladder stones may not present with any specific symptoms or may be asymptomatic. They are typically associated with conditions that cause incomplete bladder emptying, most commonly BPH. Patients may also experience a combination of urinary symptoms such as terminal hematuria, suprapubic pain, weak stream, dysuria, and more. Terminal gross hematuria with sudden cessation of voiding is a common sign of a large bladder calculus. Bladder stones can also cause urinary incontinence, dysuria, vesicovaginal fistulas, and outflow obstruction.[43][44][45][46][47] About 66% of adult patients with bladder stones, particularly those with larger calculi (>4 cm), will experience overactive bladder symptoms. However, in some cases, the only symptom may be recurrent UTIs.[13][48] Pain may be present at the tip of the penis or anywhere in the scrotum, pelvis, or perineum. In some cases, a distended bladder may be palpable, but the stone itself is typically not. Due to the vague nature of the signs and symptoms, a definitive diagnosis usually requires cystoscopy or imaging. In the past, a definitive diagnosis was sometimes made by passing a Van Buren sound. When the sound made contact with a bladder stone, it would produce a "click" sound along with a transmitted vibration. Even today, "sounding" refers to the exploration of a bodily cavity with a solid probe to detect abnormalities by touch, feel, or sound. However, this technique is now of historical interest only and is no longer used clinically, as modern imaging technology and flexible cystoscopy are more commonly available (see Images. Interior Anatomy of the Urinary Bladder and Vertical Section of the Urinary Bladder Wall).

Urinalysis in affected individuals may reveal blood, nitrites, or leukocytes, as well as a low urinary pH and signs of a UTI. A plain x-ray or KUB (kidney, ureter, and bladder) x-ray is often the first diagnostic study ordered, but in adult men, the stone may not be calcified (eg, uric acid stones), making plain x-rays insufficient. Computed tomography (CT) or bladder ultrasound can reliably detect bladder stones, with stones typically appearing as hyperechoic areas with shadowing on ultrasound. Cystoscopy can confirm the diagnosis (see Image. Computed Tomography Scan of the Pelvis). Ammonium urate is radiolucent but may develop a calcific coating, which makes it visible on x-rays. If a bladder filling defect moves when the patient is repositioned, it is likely a bladder stone. Other possibilities include a blood clot, fungal ball, or a papillary urothelial tumor on a long stalk. Given that most patients will also present with associated pelvic pain, hematuria, voiding difficulties, or a history of urolithiasis, cystoscopy is often performed. This procedure will definitively identify any bladder calculi.

Medical Therapy Dissolution of bladder stones, particularly uric acid stones, can sometimes be achieved with oral alkalinizing agents alone, provided the required higher pH level (usually between 6.5 and 7) can be maintained long enough. This technique is usually performed using oral potassium citrate, which can be supplemented with sodium bicarbonate if necessary. For most patients, this requires approximately 60 mEq of potassium citrate per day. Serum potassium levels and urinary pH levels should be monitored regularly during this therapy, and the dosage of potassium citrate should be titrated to maintain the optimal pH level.[49][50][51] Patients with a history of nephrolithiasis may benefit from a metabolic evaluation, which includes a 24-hour urine test to assess kidney stone risk factors and guide prophylactic therapy. Citric acid, glucono-delta-lactone, and magnesium carbonate can dissolve struvite (infection-related) stones but require the use of irrigating catheters. Due to the slow dissolution rate, this treatment is used infrequently.[52] Calcium phosphate is the primary component of the encrustations and debris that commonly clog urinary stents and catheters. Calcium phosphate forms only in an alkaline environment and can be dissolved with a mild acid. Periodic bladder instillations of a 0.25% acetic acid solution can help dissolve calcium phosphate crystals, reducing the risk of bladder stone formation. This approach also helps maintain the patency of Foley catheters and suprapubic tubes in patients whose urinary drainage tubes are prone to early clogging due to debris. Surgical Therapy Most bladder stones can be managed with endoscopic surgery. The underlying cause should also be addressed concurrently, when possible.[53] Most guidelines recommend treating bladder outlet obstruction when vesical calculi are present, with multiple studies supporting this approach.[27][54][55][56] However, as bladder stone formation is multifactorial, some recent reviews have questioned this recommendation, advocating for individualized decision-making instead.[57]

Most bladder stones can be managed with endoscopic surgery. The underlying cause should also be addressed concurrently, when possible.[53] Most guidelines recommend treating bladder outlet obstruction when vesical calculi are present, with multiple studies supporting this approach.[27][54][55][56] However, as bladder stone formation is multifactorial, some recent reviews have questioned this recommendation, advocating for individualized decision-making instead.[57] Cystolitholapaxy can be performed cystoscopically for most types of bladder stones. Various disruptive or ablative therapies, including lasers, pneumatic-powered mechanical contact devices, ultrasound, and direct mechanical crushing with a lithotrite, can be used. Electrohydraulic devices are generally not used for bladder stones due to the tendency of the calculi to move, resulting in higher rates of mucosal bladder injury. Ultrasound and lithoclast devices typically fragment bladder stones more quickly than lasers, although all methods are considered effective. Laser treatment of bladder stones is increasingly becoming the standard due to its high stone-free success rate, low complication rate, and the ability to perform other endourological procedures, such as prostate resections and ureteroscopy.[58][59] Extracorporeal shockwave lithotripsy (ESWL) can be equally effective for bladder stones, but the treatment head must be positioned above the patient (or the patient placed in a prone position) and may require multiple treatment sessions (up to 3) to achieve comparable results.[60][61][62][63][64][65][66] An advantage of ESWL is that it is the least invasive surgical option.[61][67] ESWL may also be used in children with bladder calculi.[60][68] Stones impacted in the urethra can be repositioned into the bladder and treated with ESWL.[65]

Extracorporeal shockwave lithotripsy (ESWL) can be equally effective for bladder stones, but the treatment head must be positioned above the patient (or the patient placed in a prone position) and may require multiple treatment sessions (up to 3) to achieve comparable results.[60][61][62][63][64][65][66] An advantage of ESWL is that it is the least invasive surgical option.[61][67] ESWL may also be used in children with bladder calculi.[60][68] Stones impacted in the urethra can be repositioned into the bladder and treated with ESWL.[65] Percutaneous suprapubic cystolitholapaxy is the preferred treatment for pediatric bladder stones, especially in males aged 16 or younger, to minimize urethral trauma.[69] Larger caliber instruments can be placed suprapubically rather than transurethrally, which is particularly advantageous in pediatric patients. A combined procedure using both suprapubic and cystoscopic approaches may be used in some cases. In adult male patients with outlet obstruction, transurethral resection of the prostate (TURP) or a similar procedure is recommended, when indicated, immediately after the stone has been fragmented and removed.[70] In cases of extremely large bladder stones or prostates, open suprapubic surgery may be considered. This approach allows for the removal of the intact stone, followed by an open suprapubic prostatectomy, typically for prostates larger than 75 grams. The main advantages of open suprapubic cystostomy for bladder stone removal include reduced overall surgery time (approximately half the duration of endoscopic procedures), easy removal of large or multiple stones, the ability to remove stones difficult to fragment endoscopically, and the capability to handle stones adhered to the bladder lining. However, the disadvantages of this approach include longer hospital stays, additional postoperative pain, the need for an abdominal incision and drains, possible wound complications, and prolonged Foley catheterization time.

In cases of extremely large bladder stones or prostates, open suprapubic surgery may be considered. This approach allows for the removal of the intact stone, followed by an open suprapubic prostatectomy, typically for prostates larger than 75 grams. The main advantages of open suprapubic cystostomy for bladder stone removal include reduced overall surgery time (approximately half the duration of endoscopic procedures), easy removal of large or multiple stones, the ability to remove stones difficult to fragment endoscopically, and the capability to handle stones adhered to the bladder lining. However, the disadvantages of this approach include longer hospital stays, additional postoperative pain, the need for an abdominal incision and drains, possible wound complications, and prolonged Foley catheterization time. Bladder stones are rarely reported after renal transplantation, but when they occur, they are often associated with the use of nonabsorbable suture material.[70] Treatment of bladder stones in this population is similar to that for other patients with vesical calculi. Stone removal from the augmented bladder or urinary diversions may be performed using endoscopic, percutaneous, robotic, or open surgery, depending on the clinical situation.[71][72][73]

The differential diagnoses of bladder stones include: Benign prostatic hyperplasia Clot Fungus ball Papillary urothelial carcinoma Passed renal or ureteral calculus Sloughed papilla Urinary tract infection

The prognosis for bladder stones is generally favorable when treated appropriately. Treatment depends on the underlying cause of the bladder stones. Small bladder stones may pass easily, but larger stones can become lodged at the bladder neck or in the urethra, obstructing urine flow. If left untreated, bladder stones can lead to urinary tract damage, recurrent stone formation, bladder damage, urinary retention, or infection.

Bladder stones, particularly larger calculi, can lead to various complications, including: Frequent urination Hematuria Urinary obstruction Pain Possible association with bladder cancer Urethral obstruction Urinary retention Urinary tract infections

Once bladder stones have developed in a patient, the risk of recurrence increases. Identifying and addressing the underlying cause is crucial in preventing future stone formation. Patients should be advised to maintain adequate hydration, as increased water intake helps prevent stone formation by diluting minerals that could otherwise precipitate in the urinary tract. If an enlarged prostate is causing obstruction, surgical intervention may be necessary to prevent urinary stasis and reduce the risk of recurrent stones.

A metabolic evaluation, including 24-hour urine testing, a basic metabolic panel, and serum uric acid levels, is recommended for all patients with bladder calculi, particularly those with uric acid stones, nephrolithiasis, bladder stones without identifiable outlet obstruction or nidus, recurrent bladder stones, or a strong family history of urinary lithiasis.

Bladder stones are relatively uncommon in Western countries but continue to be a significant concern in many parts of the world. One of the primary causative factors is the failure to regularly empty the bladder. Catheters that are not changed for prolonged periods can predispose patients to bladder calculi. When Foley catheters are removed traumatically, it is crucial to inspect the catheter to ensure no balloon fragments or other pieces remain behind. All members of the interprofessional healthcare care team must be aware of the risk of retained balloon fragments inside the bladder in such patients, as these fragments can eventually calcify. In such cases, cystoscopy, performed by a urologist and assisted by a nurse, is necessary to remove any retained fragments and prevent complications. More frequent catheter changes and the judicious use of citric acid, glucono-delta-lactone with magnesium carbonate, and 0.25% acetic acid solutions can help minimize bladder stone formation, calcium phosphate deposits, and catheter encrustations. Pharmacists play a critical role in assessing drug treatments, identifying potential interactions, ensuring medication compliance, and reporting concerns to the interprofessional healthcare team. Specialty urologic nurses coordinate patient care, facilitate communication among team members, and provide comprehensive patient education. Close collaboration and coordination between urology, primary care, pharmacy, and nursing staff are essential to reducing the incidence of preventable bladder stones.[74]