Türk.qxp 25/9/08 12:12 pm Page 89
Update on Urinary Stone Treatment
a report by
Assistant Medical Director, Department of Urology, Rudolfstiftung Hospital, Vienna
The American Urological Association (AUA) and the European Excretory Urography
Association of Urology (EAU) co-operated to develop new guidelines Excretory urography or intravenous pyelography (IVP) has been
for urolithiasis. The current article is necessary because major advances established as the gold standard in cases of acute renal colic. The
have been made in the field of urolithiasis, and the most significant administration of contrast medium, which is required for this
changes in the last few years will be presented here. investigation, limits its use. The administration of contrast medium is
contraindicated in cases of allergy, limited global renal function,
Diagnosis untreated hyperthyroidism, the intake of metformin and
What we need to know has remained the same throughout the paraproteinaemia, and it may aggravate the pain of acute colic. Its
decades if urolithiasis is suspected, and includes confirmation of the sensitivity and specificity are a little below those of CT. The excretion of
diagnosis of urolithiasis, the position and size of stones, anatomy of contrast medium provides additional information about renal function.
the urinary tract, grade of obstruction and differentiation between
radiolucent and radiopaque stones. Observation and Medical Expulsive Therapy
In cases of symptomatic stones and stone fragments after shock-wave
In addition to medical history and the required clinical investigation lithotripsy (SWL), it is increasingly considered important to combine
and laboratory examination of blood and urine, other diagnostic observation with medical therapy. Apart from symptomatic therapy
procedures are available, including ultrasound, plain films of the and non-steroidal antiphlogistics (NSARs), data exist concerning
kidneys, ureters and bladder (KUB), non-enhanced helical computed calcium channel blockers such as nifedipine and alpha-receptor
tomography (CT) and excretory urography. However, the importance blockers. The application of alpha-receptor blockers in particular
of the individual procedures has changed. appears to be beneficial in cases of stones or stone fragments in the
distal ureter. These medications, such as tamsulosin, are primarily
Ultrasound known from the treatment of symptomatic prostate hyperplasia. Their
This is the most widespread method of investigation. It creates no application in cases of ureteral stones has been incorporated in all new
radiation load and causes no pain for the patient. Stones in the kidney guidelines but they are used on an ‘off-label’ basis, depending on
can usually be well visualised by ultrasound, and some stones are also national laws. A meta-analysis of six studies examining alpha blockers
seen in the proximal and distal portions of the ureter. Visualisation of revealed a stone passage rate of 81% (range 72–88%) for ureteral
the distal ureter is facilitated by a full bladder. Additionally, the grade stones measuring ≤10mm. This signifies a clear and partly statistically
of dilatation of the urinary collecting system can be visualised, but not significant increase regarding the likelihood of stone passage.
the grade of obstruction.
Plain Film, Kidney–Ureter–Bladder Only uric acid stones can be dissolved by oral chemolitholysis. For this
KUB provides additional information about the radiopacity of a purpose the urinary pH must be set between 7.0 and 7.2 by the
previously detected stone after ultrasound or CT. In comparison with application of alkaline citrates or sodium bicarbonate. Irrigation
earlier X-rays of the patient, this method may provide a diagnosis on chemolitholysis can be performed only in the presence of stones
its own. KUB is a perfect imaging modality for follow-up after composed of magnesium ammonium phosphate and carbonate
treatment of radiopaque stones. apatite, and is performed with a solution of hemiacidrin (renacidin).
The method is not given much importance in the new guidelines.
Non-enhanced Helical Computed Tomography Irrigation litholysis requires careful planning and great expertise.
CT is marked by the highest sensitivity (91–100%) and specificity
(95–100%) to demonstrate urinary stones and may also reveal other
Christian Türk is Assistant Medical Director in the
pathologies. Information about renal function cannot be obtained without
Department of Urology at Rudolfstiftung Hospital in
the administration of contrast medium. CT can demonstrate not only
Vienna. He is a member of several societies, including the
radiopaque but also uric acid and xanthine stones, which are radiolucent
American Urology Association (AUA), the Austrian Urology
Association (OGU), the Society of Minimally Invasive
on plain films. However, it is not always possible to differentiate between
Medicine, the Society of Endourology and Extracorporeal
radiolucent and radiopaque stones by the use of CT. Today CT without
Shockwave Lithotripsy. He graduated from the University
of Vienna in 1975.
contrast medium is regarded as the most important detailed imaging
investigation after ultrasound, and has partly surpassed the value of
intravenous urography despite its higher radiation dose.
© TOUCH BRIEFINGS 2008 89