Case No. :	16
Month :	April
Year :	2000
Contributor :	Dr. Navin Khade

Clinical Profile | Discussion | References

Clinical Profile:

A 24 year old man who was operated in 1993 for tuberculosis of the lower lumbar spine developed urinary incontinence a year later and presented with further exacerbation of symptoms since 3 yrs . The patient’s prime complaint was dribbling of urine which was thought to be the result of a neurogenic bladder, consequent to previous surgery. On per rectal examination a hard mass palpated was thought to be a mass lesion.

A plain film of the pelvis (Fig 1) showed a peculiar, 8cm by 5cm, bilobed calculus in the bladder extending into the posterior urethra. An ultrasound examination (Fig 2) revealed severe bilateral hydronephrosis with a large calculus in the urinary bladder. An micturating cystourethrogram (Fig 3)demonstrated a small capacity bladder with extension of the vesical calculus into the urethra. Further, some "extravasation" of the contrast in the region of the bulbous urethra was noted. It was thought to have resulted from attempts at transurethral catheterisation of the bladder.

A "choked urethrogram" with CT sections (Figs 4,5) performed by external compression of the penile urethra , demonstrated a calculus 8.5 x 5 x 5 cms within a grossly thickened bladder with a tapered extension into the posterior urethra. An absence of contrast within most of the bladder lumen indicated possible adhesion of the calculus to bladder mucosa; reasoning that was later to be borne out at surgery.

A PCN performed about 10 days prior to surgery helped halve the level of serum creatinine from a level of 9.5mg% recorded at the time of admission.

Attempts at extracting the calculus from the bladder without instrumentation proved futile owing to adhesions with the bladder mucosa. Hence , the calculus was removed piecemeal by suprapubic electrohydraulic lithotripsy.

Fig.1
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Fig.5

Discussion :

The urethra of the adult male has a caliber of about 30F and by this token should allow free passage of calculi less than 1 cm in diameter. Urethral calculi can either be endogenous (arising within the prostate) or exogenous. The latter can further be divided into primary and the more common secondary or migrational stones. Primary stones are phosphatic in composition and lack a nucleus . The formation of primary calculi results from obstruction along the urethra eg. stricture or diverticulum. A poorly drained cavity communicating with the urethra causes stagnation and infection of contents and predisposes to calculi formation. Whilst microscopic calculi are encountered in the elderly, giant prostatic calculi of the nature described in this case report are more commonly seen in younger men.

The occurrence of urethral calculi is documented following urethral / bladder surgery and trauma to the lower urinary tract. A history of renal or bladder stones is often elicited . The posterior urethra (prostatic and membranous ) accounts for half the incidence of urethral calculi. The remainder is found along the distal urethra ( bulbous and penile).Whilst smaller urethral calculi may be completely asymptomatic, the more common symptoms of large calculi are dysuria , increased frequency / urgency of urine and gradual diminution of the urine stream leading to dribbling and finally to incontinence . Hematuria and acute urinary retention are less commonly encountered.An anatomically normal urethra, permits retrograde manipulation of stones less than 1 cm in size by means of forced irrigation or urethral sounds. Once in the bladder, the calculus can be extracted by suprapubic cystostomy. Electrohydraulic lithotripsy helps in the removal of the larger calculi as in the case described above. This technique is suitable for calculi not associated with stricture or a diverticulum of the urethra as correction of the predisposing condition would also be required. Attempts to ‘milk out’ urethral calculi or to extract those more distally located in the penile urethra with forceps is not recommended owing to the high risk of damage to the urethral mucosa with subsequent stricture formation.The very large and fixed stones of the kind described in this case report are best removed by suprapubic cystostomy followed by revision of the bladder neck as required.

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