BLADDER CALCULI (VESICAL CALCULI)

The 5 Minute Urology Consult 3rd Ed.

Mohamed S. Ismail, MBChB, MRCS, PhD

Francis Xavier Keeley, Jr., MD, FRCS

BASICS

DESCRIPTION

• Bladder calculi (also called bladder stones) are calcified material that are present in the bladder.

• It can originate primarily in the bladder.

• It can be a secondary renal stone that formed in the kidney and passed into the bladder.

• Often associated with bladder outlet obstruction in the US.

• Historically the removal of bladder calculus was performed via an incision in the perineum with the patient in a supine position and the legs elevated (the origin of the term “lithotomy position”).

EPIDEMIOLOGY

Incidence

• The incidence of bladder calculi in the Western world has significantly dropped as a result of improved diet, nutrition, and infection control

• Bladder calculi are endemic in Thailand, Burma, Indonesia, Middle east, and north Africa

• Mostly in middle age men

• In catheterized patients the incidence of developing bladder calculi is 25% in 5 yr

• The incidence in children has declined significantly however in the developing countries they are common in boys younger than 11 yr

• Vaginal prolapse and urethral surgery are common causes in women

Prevalence

• Bladder calculi constitute 10–15% of the stone burden in adult and 15–30% in children

• Data on the world wide incidence are not available

RISK FACTORS

• Urinary stasis

– Bladder outlet obstruction

Benign prostatic hyperplasia

Urethral stricture

Bladder neck contracture

– Neurogenic bladder

• Foreign body such as urethral catheter and ureteric stent that act as nidus for stone formation

• Urinary tract infection

• Urinary diversion and bladder substitution

– Secondary to foreign body, infection, and systemic acidosis

– Rarely patients may place foreign bodies in bladder that become calcified

Genetics

N/A

PATHOPHYSIOLOGY

• Bladder calculi are primarily formed in the bladder, rarely can be a secondary renal stone that has formed in the kidney and passed into the bladder

– Foreign bodies, retained catheter balloon fragments

– Patients on chronic intermittent catheterization may force pubic hair into the bladder that can become calcified over time

• Stone analysis frequently reveals uric acid stone in 50% of the cases

• Other constituents are ammonium urate, calcium oxalate, and calcium phosphate

• In infected urine, struvite stones are the most common

• In patients with spinal cord injuries (SCIs), bladder stones are often composed of struvite or calcium phosphate

• In endemic areas, low phosphate diet results in increased ammonium excretion in the urine

• Low intake of animal protein contributes to high urinary oxalate and low urinary citrate levels with increased risk of stone formation

• Solitary stone are present in 75% of cases

ASSOCIATED CONDITIONS

• Foreign bodies in the bladder

• Intermittent catheterization

• Low phosphate diet

• Low protein diet

• Urinary stasis (prostatic hypertrophy, stricture, congenital abnormalities [ureterocele], diverticulum, cystocele)

• Urinary tract infection

GENERAL PREVENTION

• Adequate hydration

• Treatment of bladder outlet obstruction

• Prevention of urinary tract infection

• Prevention of urololithiasis as appropriate

– Allopurinol for uric acid stones

– Reduce oxalate intake

– Increase urinary citrate

– Low sodium low diet

DIAGNOSIS

HISTORY

• Patients with SCI, neurogenic bladder may be at increased risk

• Bladder calculi may be asymptomatic and may be incidental finding on imaging (plain x-ray, renal ultrasound, CT, or flexible cystoscopy)

• Patients commonly presents with

– Suprapubic or perineal pain

– Irritative urinary symptoms

– Intermittent urinary stream

– Hematuria, gross, and microscopic

– Recurrent urinary tract infection

PHYSICAL EXAM

• Examine the abdomen for palpable bladder or suprapubic tenderness

• Examine the external genitalia for any abnormalities (meatal stenosis) that may contribute to outlet obstruction

• Digital rectal exam to assess for BPH and prostate cancer

DIAGNOSTIC TESTS & INTERPRETATION

Lab

• Urine analysis: Hematuria, leukocytes, and crystalluria may be present

• Urine culture and sensitivity in case of suspected infection

• Urine cytology in the presence of calculi is nonspecific

• Serum creatinine

• Stone analysis should be considered when removed

Imaging

• Calcified stones can be visible on plain x-ray (KUB)

– Stones may be densely radiopaque.

– Occasionally laminations may be visible on plain x-ray

• Uric acid and ammonium acid urate stones are radiolucent but will be seen on ultrasounds or CT scan.

• Bladder calculi may not be visible on MRI

• CT without contrast is highly sensitive and specific to detect calculi, however it is rarely used to diagnose bladder stones

Diagnostic Procedures/Surgery

• Cystoscopy to visualize the stone and guide subsequent removal of the stone

– Allows evaluation of bladder outlet obstruction or other abnormality such as bladder diverticulum

Pathologic Findings

• Acute and chronic inflammation

• Squamous metaplasia and squamous cell carcinoma can result from chronic vesical calculus irritation

DIFFERENTIAL DIAGNOSIS

• Bladder diverticulum

• Bladder malignancy with or without calcification

– Urothelial carcinoma

– Other bladder malignancies

• Chronic pelvic pain syndrome

• Fungal bezoar or blood clot

• Interstitial cystitis

• Lower urinary tract symptoms due to bladder outlet obstruction

• Overactive bladder

• Urinary tract infection

• Ureteral urolithiasis

– Distal ureteral stone can cause significant vesical irritation

TREATMENT

GENERAL MEASURES

• Surgical removal is the mainstay treatment

• Determining and correcting the cause (ie, bladder outlet obstruction) should be a priority

MEDICATION

First Line

• Medical therapy is used to treat associated urinary tract infection

• Bladder outlet obstruction is treated with alpha blockers such as tamsulosin 0.4 mg QD and 5 alpha reductase inhibitors such as dutasteride 0.5 mg QD

Second Line

• Alkalinization of urine to a PH of 6.5 in case of uric acid stones

– Use potassium citrate 60 mEq/d PO

SURGERY/OTHER PROCEDURES

• Endoscopic cystolitholapaxy using stone fragmenting forceps

• Electrohydraulic, ultrasonic, laser, and pneumatic lithotrites are used for larger or harder stones

• Large stones can be removed through small abdominal incision (open cystolitholapaxy)

• Cystolitholapaxy can be safely combined with procedures such as TURP or TUIP for bladder outlet obstruction

ADDITIONAL TREATMENT

Radiation Therapy

N/A

Additional Therapies

• ESWL has a limited role in treating bladder calculi

• Bladder outlet procedure may be necessary if urinary stasis is causing vesical calculus to improve bladder emptying

• Consideration to repair of bladder diverticulum or other anatomic abnormality if contributory

Complementary & Alternative Therapies

N/A

ONGOING CARE

PROGNOSIS

• Excellent with complete stone removal and associated bladder outlet obstruction are treated

• Metabolic stone evaluation may be considered if appropriate (ie, multiple upper tract calculi, recurrent bladder calculi, etc.)

COMPLICATIONS

• Recurrent urinary tract infection

• Squamous metaplasia

• Chronic irritation may result in secondary malignancy (ie, squamous cell carcinoma)

FOLLOW-UP

Patient Monitoring

• Urine analysis

• Flowmetry and postvoid residual

• Renal ultrasound scan to screen for upper tract urolithiasis

Patient Resources

PubMed Health: Bladder Stones http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002254/

REFERENCES

1. Huffman JL, Ginsberg DA. Calculi in the bladder and urinary diversions. In: Coe FL, Favus MJ, Pak CY, Parks JH, Preminger GM, eds. Kidney Stones: Medical and Surgical Management. Philadelphia, PA: Lippincott-Raven; 1996:1025–1034.

2. Douenias R, Rich M, Badlani G, et al. Predisposing factors in bladder calculi. Review of 100 cases. Urology. 1991;37(3):240–243.

3. Paez E, Reay E, Murthy LN, et al. Percutaneous treatment of calculi in reconstructed bladder. J Endourol. 2007;21(3):334–336.

ADDITIONAL READING

Preminger GM, Tiselius HG, Assimos DG, et al; EAU/AUA Nephrolithiasis Guideline Panel. 2007 guideline for the management of ureteral calculi. J Urol. 2007;178(6):2418–2434.

See Also (Topic, Algorithm, Media)

• Bladder Calculi (Vesical Calculi) Image