Bladder Stones

Introduction

Bladder stones form because of a build-up of minerals in the bladder, usually as a result of a condition in which the bladder cannot fully empty itself. Bladder stones are less common than kidney stones and the mechanisms of formation also differ.

Therefore, a patient with a history of bladder stones may not get kidney stones and vice versa. Bladder stones are more common in men because the prostate can cause obstruction quite commonly.

Causes

Some of the causes include:

• Benign prostatic enlargement (BPH) .
• Bladder diverticulum (pouch).
  • This forms when the bladder is chronically overstretched usually due to bladder outlet obstruction.
  • Because the pouch cannot contract during voiding, it acts as a reservoir of retained urine that cannot be emptied fully. This urine then forms bladder stones.
• Neurogenic bladder or underactive bladder.
• Foreign body in the bladder (retained materials) .
  • E.g., suture material from previous bladder surgery, encrustation from long-term catheters.
  • It acts as a nidus for sediments to start forming around and eventually, a stone is formed.
• Chronic bladder infections.
• Urethral strictures.
  • Scarring and narrowing of the tube that drains the bladder.
  • Usually caused by infections or previous passage of instruments / catheters.
  • This causes bladder outlet obstruction and incomplete emptying of urine.

How do bladder stones present?

Some patients have no symptoms and the stones are picked up incidentally on x-ray imaging done for other reasons.

The common symptoms are:

• Difficulty passing urine.
• Passing urine frequently.
• Dark or blood-stained urine.
• Interrupted urine flow.
• Pain in the lower abdomen or penis.
• Urinary infections (burning when urinating, smelly urine, frequent urge to urinate, fevers).

The rare complications of bladder stones are:

• Bladder cancer.
• Kidney damage from obstruction.
• Bladder dysfunction from chronic obstruction.
• Severe infections.

What are the investigations?

The investigations are aimed at diagnosing the bladder stone and also finding out the cause for it. Your doctor may do a rectal examination to check for enlargement of the prostate.

The investigations include:

• Bladder imaging (x-rays or ultrasound) to show the stone:
  • An ultrasound is also useful for estimating the prostate size and measuring the post-void residual volume (how much urine is left in the bladder after urinating).
• Urinalysis to check for blood or infection in the urine.
• Cystoscopy (inspection of the inside of the bladder using a tubelike camera).
  • To visualise the stone.
  • Check for causes of obstruction (e.g., enlarged prostate, urethral strictures).
  • Check for retained materials in the bladder.
  • Check bladder capacity and structure – confirm if it is an overstretched bladder that cannot contract fully, or if there is any bladder diverticulum (pouch).
• If indicated, urodynamics (bladder function study) is done to assess the bladder function:
  • Confirm if it is an underactive bladder.
  • Confirm if there is any obstruction.
  • Confirm if the bladder can empty itself fully.

What are the treatments?

Treatments are aimed at removing the stones and also treating the underlying cause.

Treating the stones

Most bladder stones can be fragmented during a cystoscopy with a laser fibre, a pneumatic device or a stone crusher device. The fragments are then washed out. Some big bladder stones are removed using open surgery. 

Treating the underlying cause

If the cause of the stone formation is not treated, the bladder stones may recur. Some patients with prostatic enlargement may need a resection of the prostate (TURP – transurethral resection of the prostate).

Those with chronic bladder infections must be treated with the appropriate antibiotics. If the bladder cannot empty itself fully, the treatments are covered here (underactive bladder).

Foreign bodies in the bladder must be removed. A bladder diverticulum can be managed with a catheter programme or surgery to remove the bladder pouch.