Urinary Bladder Stones – Bladder Calculi

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Review literatur: (Bartosh, 2004) (Schwartz and Stoller, 2000).

Definition

Bladder stones are a common form of urolithiasis of the lower urinary tract with formation of calculi in the bladder.

Epidemiology and Causes of Bladder Stones

Endemic bladder stones:

Malnutrition in developing countries causes bladder stones in children without the presence of bladder emptying disorders. Affected areas are North Africa, the Middle and Far East. Boys under 10 years suffer more often from bladder stones, since girls may pass better sandy precursors via the short urethra.

The cause of urinary bladder stone formation in children is a diet low in animal proteins, which consists mainly of cereals. Other factors include dehydration and a dietary phosphate deficiency. Pediatric bladder stones most commonly consist of ammonium acid urate with or without calcium calcium oxalate or calcium phosphate.

Secondary Bladder Stones:

Urinary bladder stones in developed countries develop usually secondary due to urinary stasis, recurrent urinary tract infections, foreign bodies or intestinal mucosa in the urinary tract (urinary diversion or augmentation).

Subvesical obstruction and bladder stones:

Postvoid residual urine (urinary stasis) is the most common cause for bladder stones (75%) and mainly affects men over 50 years old. Benign prostatic hyperplasia or neurogenic bladder emptying disorders are common causes for postvoid residual urine. Bladder stones causes by urinary stasis consist of uric acid, calcium oxalate and magnesium ammonium phosphate (infection stone).

Urinary tract infections and catheterization:

Recurrent or chronic urinary tract infections with urease-producing bacteria lead to magnesium ammonium phosphate stones.

Spinal cord injured patients with bladder catheter have a 9-fold risk for bladder stones, compared to the catheter-free patients with spinal cord injury. If intermittent self-catheterization or urinary condom are necessary, the risk of bladder stones is increased 4-fold.

Foreign body:

Foreign bodies with contact to urine cause urinary stones. Self-manipulation or iatrogenic causes lead to foreign bodies in the bladder. Examples of iatrogenic causes: suture material, clips, catheters, ureteral stents or migration of an intrauterine device.

Urinary diversion and urinary stones:

The risk of urinary stone formation (4–48%) depends on the type of urinary diversion. Urinary stones occur three times more common in continent than in incontinent urinary diversion. Risk factors are urinary stasis, mucus production, urinary tract infections, clips, non-absorbable suture material, need for catheterization and metabolic disorders. Usually, urinary stones in urinary diversion are magnesium ammonium phosphate stones (infection stones).

Signs and Symptoms of Bladder Calculi

Childhood Symptoms in Endemic Bladder Stones:

• Abdominal pain
• Interrupted urine flow
• Dysuria, alguria, frequency
• Need to manipulate the penis

Symptoms due to Secondary Bladder Stones:

• Recurrent urinary tract infections
• Dysuria, alguria, frequency
• Interrupted urinary flow or urinary retention
• The majority of bladder stones cause no additional problems in addition to the underlying bladder disorder.

Diagnostic Work-Up of Bladder Calculi

Ultrasonography:

Bladder stones imaging with ultrasonography shows an echogenic mass in the urinary bladder with posterior acoustic shadow. After repositioning, the echogenic mass should move due to gravity. Imaging is most reliably with a filled bladder.

Ultrasonography of a urinary bladder stone: by courtesy, Prof. Dr. R. Harzmann, Augsburg.

Abdominal Radiograph:

Many bladder stones are radiopaque, but some are obscured by overlying bowel gas shadows or are not radiopaque.

Cystography:

Non-radiopaque urinary bladder stones can be detected by cystography by causing a filling defect of the contrast media [fig. cystography with bladder stones].

Cystography showing multiple diverticula: the right diverticulum is filled with a bladder stone, as shown by the double contrast. By courtesy, Dr. R. Gumpinger, Kempten.

Computed Tomography:

CT without contrast media is a very accurate method in the diagnosis of urinary bladder stones.

Cystoscopy:

Cystoscopy is a reliable method in the diagnosis of bladder stones and is also necessary for treatment planning of the underlying disease (prostate size? urethral stricture? bladder diverticula?).

Treatment of Urinary Bladder Stones

The majority of bladder stones can be treated endoscopically. Treatment options are influenced by the anatomy, etiology, concomitant diseases and stone size.

Extracorporeal Shock Wave Lithotripsy (ESWL):

ESWL of bladder stones is a treatment option for children or patients with a high risk for anesthesia. Without treatment of the underlying cause, there is a high risk of recurrence.

Transurethral Cystolitholapaxy:

Please see technique and complications of transurethral cystolitholapaxy for details. Depending on the course of the operation, a TURP (if indicated) is performed afterwards.

Percutaneous Cystolithotomy:

Percutaneous Cystolithotomy is indicated in children or patients with large stone burden. After percutaneous puncture of the bladder and insertion of a guide wire, an access tract with 24–36 CH is established. Stone fragmentation and removal is similar to percutaneous nephrolithotomy.

Open Cystolithotomy (Sectio alta):

The decision between endoscopic or open cystolithotomy depends on the size of the stones, number of stones and size of the prostatem, if a simultaneous surgical BPH therapy is sought. Please see section technique and complications of open cystolithotomy for details.

Treatment of Endemic Bladder Stones:

After surgical removal of the bladder stones (see above), a change in diet is needed to prevent recurrence of bladder stones: a diet rich of cow's milk and mixed cereals.