Lower urinary tract stones include bladder stones and urethral stones. Primary bladder stones (primary vesical calculi) are more commonly observed in boys and are associated with malnutrition and low-protein diets. Secondary bladder stones (secondary vesical calculi) are commonly seen in conditions such as benign prostatic hyperplasia, bladder diverticula, neurogenic bladder, the presence of foreign bodies, or stone migration from the kidneys or ureters into the bladder.
Urethral stones (urethral calculi) primarily occur in men and are most often secondary to stones migrating from the kidney or bladder. Urethral stones can also occur in association with urethral strictures, urethral diverticula, or foreign bodies. Most urethral stones are located in the anterior urethra.
Clinical Manifestations
The typical symptoms of bladder stones include sudden interruption of urination, pain radiating to the distal urethra or glans penis, and associated urinary difficulty along with bladder irritative symptoms. Urethral stones typically present with difficulty in urination, dribbling urination, painful urination, and in severe cases, acute urinary retention and severe perineal pain. In addition to these typical symptoms, lower urinary tract stones are often accompanied by hematuria and infection. Stones within diverticula sometimes present solely as urinary tract infections.
Diagnosis
The diagnosis is based on typical symptoms and imaging studies, with attention given to identifying underlying causes of the stones, such as benign prostatic hyperplasia or urethral strictures. Anterior urethral stones may be palpable along the urethra, while posterior urethral stones may be detected during a rectal examination.
Common auxiliary diagnostic methods include:
- Ultrasound Examination: Capable of identifying echogenic masses with posterior acoustic shadowing in the bladder and posterior urethra, along with the detection of associated conditions such as bladder diverticula or benign prostatic hyperplasia.
- Plain X-ray Imaging: Useful for visualizing the majority of stones.
- Non-Contrast CT Scanning: Provides visualization of nearly all stones.
- Cystoscopy and Urethroscopy: Offers direct visualization of stones and can also aid in identifying pathological changes in the bladder or urethra.
Treatment
Bladder stones are treated surgically, and any underlying causes should be simultaneously addressed. Severe bladder infection requires treatment with antimicrobial agents. If urinary retention is present, catheterization is performed to facilitate urine drainage and infection control.
Transurethral Cystoscopic Stone Removal or Lithotripsy
Most stones can be managed using mechanical lithotripsy with stone forceps, followed by extraction. This approach is suitable for stones with a diameter of less than 2 cm. Larger stones may require fragmentation using ultrasound, laser, or pneumatic lithotripsy techniques.
Suprapubic Cystolithotomy
This conventional open surgical approach is used for exceptionally large or hard stones or in cases involving bladder diverticular disease. However, it is no longer considered the first-line treatment option.
The treatment of urethral stones depends on their location. For stones in the navicular fossa, sterile liquid paraffin can be instilled into the urethra, allowing the stone to be pushed gently toward the urethral meatus where it can be extracted with vascular forceps. For anterior urethral stones, treatment involves perineal nerve block anesthesia, compression of the urethra proximal to the stone to prevent its regression, injection of sterile liquid paraffin, and gentle advancement of the stone toward the distal urethra, followed by retrieval with a snare or forceps. When extraction is difficult, endoscopic fragmentation and removal may be required. Rough or forceful handling should be avoided to minimize the risk of urethral stricture, and urethral incision for stone removal should be avoided whenever possible.
For posterior urethral stones, a urethral sound or cystoscope may be used to gently push the stone into the bladder, where it is subsequently treated as a bladder stone.